• Omega

    From Cursitor Doom@21:1/5 to All on Sun Jun 30 08:44:34 2024
    Gentlemen,

    For more decades than I care to remember, I've been using formulae
    such as Xc= 1/2pifL, Xl=2pifC, Fo=1/2pisqrtLC and such like without
    even giving a thought as to how omega gets involved in so many aspects
    of RF. BTW, that's a lower-case, small omega meaning 2*pi*the-frequency-of-interest rather than the large Omega which is
    already reserved for Ohms. How does it keep cropping up? What's so
    special about the constant 6.283 and from what is it derived?
    Just curious...

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From piglet@21:1/5 to Cursitor Doom on Sun Jun 30 11:57:21 2024
    On 30/06/2024 8:44 am, Cursitor Doom wrote:
    Gentlemen,

    For more decades than I care to remember, I've been using formulae
    such as Xc= 1/2pifL, Xl=2pifC, Fo=1/2pisqrtLC and such like without
    even giving a thought as to how omega gets involved in so many aspects
    of RF. BTW, that's a lower-case, small omega meaning 2*pi*the-frequency-of-interest rather than the large Omega which is
    already reserved for Ohms. How does it keep cropping up? What's so
    special about the constant 6.283 and from what is it derived?
    Just curious...


    Watch this (your question is addressed at 2:07)

    <https://youtu.be/Vv2W5vJFqFo?si=eX3ZONUzzpNNxGtg>

    piglet

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to All on Sun Jun 30 13:13:31 2024
    On Sun, 30 Jun 2024 11:57:21 +0100, piglet <erichpwagner@hotmail.com>
    wrote:

    On 30/06/2024 8:44 am, Cursitor Doom wrote:
    Gentlemen,

    For more decades than I care to remember, I've been using formulae
    such as Xc= 1/2pifL, Xl=2pifC, Fo=1/2pisqrtLC and such like without
    even giving a thought as to how omega gets involved in so many aspects
    of RF. BTW, that's a lower-case, small omega meaning
    2*pi*the-frequency-of-interest rather than the large Omega which is
    already reserved for Ohms. How does it keep cropping up? What's so
    special about the constant 6.283 and from what is it derived?
    Just curious...


    Watch this (your question is addressed at 2:07)

    <https://youtu.be/Vv2W5vJFqFo?si=eX3ZONUzzpNNxGtg>

    piglet


    Thanks, Erich. I did wonder if radians had something to do with it.
    However, knowing that 2 pi radians = 360 degrees or a full wavelength
    doesn't help me understand why this figure multiplied by the frequency multiplied by the inductance gives us the reactance of a coil. Small
    omega therefore equals one second's worth of signal and I don't get
    how multipying that by the inductance amounts to the reactance!

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to All on Sun Jun 30 06:05:41 2024
    On Sun, 30 Jun 2024 08:44:34 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    Gentlemen,

    For more decades than I care to remember, I've been using formulae
    such as Xc= 1/2pifL, Xl=2pifC, Fo=1/2pisqrtLC and such like without
    even giving a thought as to how omega gets involved in so many aspects
    of RF. BTW, that's a lower-case, small omega meaning >2*pi*the-frequency-of-interest rather than the large Omega which is
    already reserved for Ohms. How does it keep cropping up? What's so
    special about the constant 6.283 and from what is it derived?
    Just curious...

    2 * pi.

    If a thing 1 unit in radius rotates one time per second, its
    circumference is 2pi so its rim velocity is 2pi/second.

    A capacitor current depends on the rate of change of the voltage.

    I = CV/T

    A 1 volt peak 1 Hz sine wave has its max rate of change at the zero
    crossing, and that rate is 2pi volts/second. So 1 farad driven with a
    1 Hz 1 volt peak sine wave has a peak current of 2pi amps.

    You can Spice all that to get a feel for things.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to All on Sun Jun 30 14:23:24 2024
    On Sun, 30 Jun 2024 06:05:41 -0700, john larkin
    <jlarkin_highland_tech> wrote:

    On Sun, 30 Jun 2024 08:44:34 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    Gentlemen,

    For more decades than I care to remember, I've been using formulae
    such as Xc= 1/2pifL, Xl=2pifC, Fo=1/2pisqrtLC and such like without
    even giving a thought as to how omega gets involved in so many aspects
    of RF. BTW, that's a lower-case, small omega meaning >>2*pi*the-frequency-of-interest rather than the large Omega which is
    already reserved for Ohms. How does it keep cropping up? What's so
    special about the constant 6.283 and from what is it derived?
    Just curious...

    2 * pi.

    If a thing 1 unit in radius rotates one time per second, its
    circumference is 2pi so its rim velocity is 2pi/second.

    A capacitor current depends on the rate of change of the voltage.

    I = CV/T

    A 1 volt peak 1 Hz sine wave has its max rate of change at the zero >crossing, and that rate is 2pi volts/second. So 1 farad driven with a
    1 Hz 1 volt peak sine wave has a peak current of 2pi amps.

    You can Spice all that to get a feel for things.

    Thanks, John. This is the fundamental stuff I just overlook since the
    need for it so rarely crops up. It's easier to take an abstraction
    level higher and lose all the vital detail in the process.
    You're up early today. Off to church are we?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Bill Sloman@21:1/5 to Cursitor Doom on Sun Jun 30 23:22:20 2024
    On 30/06/2024 10:13 pm, Cursitor Doom wrote:
    On Sun, 30 Jun 2024 11:57:21 +0100, piglet <erichpwagner@hotmail.com>
    wrote:

    On 30/06/2024 8:44 am, Cursitor Doom wrote:
    Gentlemen,

    For more decades than I care to remember, I've been using formulae
    such as Xc= 1/2pifL, Xl=2pifC, Fo=1/2pisqrtLC and such like without
    even giving a thought as to how omega gets involved in so many aspects
    of RF. BTW, that's a lower-case, small omega meaning
    2*pi*the-frequency-of-interest rather than the large Omega which is
    already reserved for Ohms. How does it keep cropping up? What's so
    special about the constant 6.283 and from what is it derived?
    Just curious...


    Watch this (your question is addressed at 2:07)

    <https://youtu.be/Vv2W5vJFqFo?si=eX3ZONUzzpNNxGtg>

    Thanks, Erich. I did wonder if radians had something to do with it.
    However, knowing that 2 pi radians = 360 degrees or a full wavelength
    doesn't help me understand why this figure multiplied by the frequency multiplied by the inductance gives us the reactance of a coil. Small
    omega therefore equals one second's worth of signal and I don't get
    how multipying that by the inductance amounts to the reactance!

    You'd probably have to master Maxwell's equations before you got it. My
    second year university math course was all about differential equations
    and how to integrate them. It never made a great deal of sense to me,
    but by the time I'd got through it, the differential equation involved
    in electronics were familiar enough that I didn't have any trouble understanding that radians per second made sense, and it didn't prompt
    any bursts of curiosity.

    That was the point in my career where I noticed for myself that
    magnetism made sense as the relativistic consequence of the forces
    between moving electric charges, and got told that Wheeler was writing a textbook around that idea.

    https://en.wikipedia.org/wiki/Wheeler%E2%80%93Feynman_absorber_theory

    He'd published it a decade earlier.

    If you don't get the right education, some idea can be inaccessible.

    --
    Bill Sloman, Sydney

    --
    This email has been checked for viruses by Norton antivirus software. www.norton.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to Phil Hobbs on Sun Jun 30 13:51:42 2024
    Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
    On 2024-06-30 03:44, Cursitor Doom wrote:
    Gentlemen,

    For more decades than I care to remember, I've been using formulae
    such as Xc= 1/2pifL, Xl=2pifC, Fo=1/2pisqrtLC and such like without
    even giving a thought as to how omega gets involved in so many aspects
    of RF. BTW, that's a lower-case, small omega meaning
    2*pi*the-frequency-of-interest rather than the large Omega which is
    already reserved for Ohms. How does it keep cropping up? What's so
    special about the constant 6.283 and from what is it derived?
    Just curious...


    As an old colleague of mine from grad school would say, "It just comes
    out in the math." ;)

    The 2*pi factor comes from the time domain / frequency domain
    conversion, and the basic behavior of linear differential equations with constant coefficients. (That's magic.(*)) For now we'll just talk about
    LR circuits and pulses.

    A 1-second pulse (time domain) has an equivalent width of 1 Hz
    (frequency domain, including negative frequencies). That's pretty
    intuitive, and shows that seconds and cycles per second are in some
    sense the same 'size'. The two scale inversely, e.g. a 1-ms pulse has
    an equivalent width of 1 kHz, also pretty intuitive. (Equivalent width
    is the mathematical quantity for which this 1-Hz/1-s inverse relation
    holds exactly, independent of the shape of the waveform.)

    Moving gently towards the frequency domain, we have the ideas of
    resistance and reactance. Resistance is defined by

    V = IR, (1)

    independent of both time and frequency. Actual resistors generally
    behave very much that way, over some reasonable range of frequencies and power levels. Either V or I can be taken as the independent variable,
    i.e. the one corresponding to the dial setting on the power supply, and
    the equation gives you the other (dependent) variable.

    A 1-Hz sine wave of unit amplitude at frequency f is given by

    I = sin(2 pi f t), (2)

    and the reactance of an inductance L is

    X = 2 pi f L. (3)

    The reactance is analogous to resistance, except that since inductance couples to dI/dt rather than I. From the definition of inductance,

    V = L dI/dt. (4)

    Plugging (2) into (4), you get

    V = L dI/dt = L * (2 pi f) cos(2 pi f t) = X_L cos(2 pi f t), (5)

    where X_L is the inductive reactance.

    We see that the voltage dropped by the inductance is phase shifted by
    1/4 cycle. Since the cosine reaches its peak at 0, where the current
    (the independent variable) is just going positive, we can say that the voltage waveform is _advanced_ by a quarter cycle, i.e. that the voltage
    is doing what the imposed current was doing a quarter cycle previously.
    (This seems like a fine point, but it's crucial to keeping the sign of
    the phase shift right, especially when you're a physics/engineering
    amphibian like me--the two disciplines use opposite sign conventions.)

    Besides the phase shift, the voltage across the inductance has an extra factor of 2 pi f. This is often written as a Greek lowercase omega,
    which for all you slipshod HTML-mode types is &omega; = 2&pi;f.

    Writing the sine wave as

    I = sin(&omega;t) (6)

    is faster, but the factor of 2 pi in amplitude keeps coming up, which it inescapably must, and it doesn't even really simplify the math much.

    For instance, if we apply a 1-V step function across a series RL with a
    time constant

    tau = L/R = 1 second, (7)

    the voltage on the resistor is

    V = 1-exp(-t). (8)

    In the frequency domain, the phase shift makes things a bit more
    complicated. If we use our nice real-valued sinusoidal current waveform
    (6) that we can see on a scope, then (after a small flurry of math), the voltage on the resistor comes out as

    V = sin(t - arctan(omega L/R)) / sqrt(1 + (omega L / R)**2). (9)

    This is because sines and cosines actually are sums of components of
    both positive and negative frequency, and which don't behave the same
    way when you differentiate them:

    sin(omega t) = 1/2 * (exp(j omega t) - exp(-j omega t)) (10)

    and

    cos(omega t) = 1/2 * (exp(j omega t) + exp(-j omega t)). (11)

    By switching to complex notation, and making a gentlemen's agreement to
    take the real part of everything before we start predicting actual
    measurable quantities, the math gets much simpler. Our sinusoidal input voltage becomes

    Vin = exp(j omega t) (12)

    and the voltage across the resistor is just the voltage divider thing:

    V/Vin = R / (R + j omega L). (13)

    At low frequencies, the resistance dominates and the inductance doesn't
    do anything much, just a small phase shift

    theta ~= - j omega L/R.

    At high frequencies, the inductance dominates. In the middle, the two effects become comparable at a frequency

    omega0 = R/L.

    At that frequency, the phase shift is -45 degrees and the amplitude is
    down by 1/sqrt(2) (-3 dB) and the power dissipated in the resistor falls
    to half of its DC value.

    If we're using the series LR as a lowpass filter, that's the frequency
    that divides the passband, where the signal mostly gets through, from
    the stopband, where it mostly doesn't.

    So when we think in the time domain, a 1-ohm/1-henry LR circuit responds
    in about a second, whereas in the frequency domain, its bandwidth rolls
    off at omega = 1, i.e. at 1/(2 pi) Hz.

    With sinusoidal waveforms, we can think of 1 second corresponding to 1
    radian per second, whereas with pulses, a 1 second pulse has a 1-Hz-wide spectrum (counting negative frequencies).

    Thing is, a sine wave varies smoothly and goes through a much more complicated evolution (positive to negative and back) within a cycle, so
    it just takes longer, by a factor that turns out to be 2*pi.

    Cheers

    Phil Hobbs


    (*) Kipling, "How the Rhinoceros got his skin"


    Belay that last bit—it’s exactly backwards. I’ll fix it when I get back from church.

    Cheers

    Phil Hobbs

    --
    Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to Cursitor Doom on Sun Jun 30 09:31:29 2024
    On 2024-06-30 03:44, Cursitor Doom wrote:
    Gentlemen,

    For more decades than I care to remember, I've been using formulae
    such as Xc= 1/2pifL, Xl=2pifC, Fo=1/2pisqrtLC and such like without
    even giving a thought as to how omega gets involved in so many aspects
    of RF. BTW, that's a lower-case, small omega meaning 2*pi*the-frequency-of-interest rather than the large Omega which is
    already reserved for Ohms. How does it keep cropping up? What's so
    special about the constant 6.283 and from what is it derived?
    Just curious...


    As an old colleague of mine from grad school would say, "It just comes
    out in the math." ;)

    The 2*pi factor comes from the time domain / frequency domain
    conversion, and the basic behavior of linear differential equations with constant coefficients. (That's magic.(*)) For now we'll just talk about
    LR circuits and pulses.

    A 1-second pulse (time domain) has an equivalent width of 1 Hz
    (frequency domain, including negative frequencies). That's pretty
    intuitive, and shows that seconds and cycles per second are in some
    sense the same 'size'. The two scale inversely, e.g. a 1-ms pulse has
    an equivalent width of 1 kHz, also pretty intuitive. (Equivalent width
    is the mathematical quantity for which this 1-Hz/1-s inverse relation
    holds exactly, independent of the shape of the waveform.)

    Moving gently towards the frequency domain, we have the ideas of
    resistance and reactance. Resistance is defined by

    V = IR, (1)

    independent of both time and frequency. Actual resistors generally
    behave very much that way, over some reasonable range of frequencies and
    power levels. Either V or I can be taken as the independent variable,
    i.e. the one corresponding to the dial setting on the power supply, and
    the equation gives you the other (dependent) variable.

    A 1-Hz sine wave of unit amplitude at frequency f is given by

    I = sin(2 pi f t), (2)

    and the reactance of an inductance L is

    X = 2 pi f L. (3)

    The reactance is analogous to resistance, except that since inductance
    couples to dI/dt rather than I. From the definition of inductance,

    V = L dI/dt. (4)

    Plugging (2) into (4), you get

    V = L dI/dt = L * (2 pi f) cos(2 pi f t) = X_L cos(2 pi f t), (5)

    where X_L is the inductive reactance.

    We see that the voltage dropped by the inductance is phase shifted by
    1/4 cycle. Since the cosine reaches its peak at 0, where the current
    (the independent variable) is just going positive, we can say that the
    voltage waveform is _advanced_ by a quarter cycle, i.e. that the voltage
    is doing what the imposed current was doing a quarter cycle previously.
    (This seems like a fine point, but it's crucial to keeping the sign of
    the phase shift right, especially when you're a physics/engineering
    amphibian like me--the two disciplines use opposite sign conventions.)

    Besides the phase shift, the voltage across the inductance has an extra
    factor of 2 pi f. This is often written as a Greek lowercase omega,
    which for all you slipshod HTML-mode types is &omega; = 2&pi;f.

    Writing the sine wave as

    I = sin(&omega;t) (6)

    is faster, but the factor of 2 pi in amplitude keeps coming up, which it inescapably must, and it doesn't even really simplify the math much.

    For instance, if we apply a 1-V step function across a series RL with a
    time constant

    tau = L/R = 1 second, (7)

    the voltage on the resistor is

    V = 1-exp(-t). (8)

    In the frequency domain, the phase shift makes things a bit more
    complicated. If we use our nice real-valued sinusoidal current waveform
    (6) that we can see on a scope, then (after a small flurry of math), the voltage on the resistor comes out as

    V = sin(t - arctan(omega L/R)) / sqrt(1 + (omega L / R)**2). (9)

    This is because sines and cosines actually are sums of components of
    both positive and negative frequency, and which don't behave the same
    way when you differentiate them:

    sin(omega t) = 1/2 * (exp(j omega t) - exp(-j omega t)) (10)

    and

    cos(omega t) = 1/2 * (exp(j omega t) + exp(-j omega t)). (11)

    By switching to complex notation, and making a gentlemen's agreement to
    take the real part of everything before we start predicting actual
    measurable quantities, the math gets much simpler. Our sinusoidal input voltage becomes

    Vin = exp(j omega t) (12)

    and the voltage across the resistor is just the voltage divider thing:

    V/Vin = R / (R + j omega L). (13)

    At low frequencies, the resistance dominates and the inductance doesn't
    do anything much, just a small phase shift

    theta ~= - j omega L/R.

    At high frequencies, the inductance dominates. In the middle, the two
    effects become comparable at a frequency

    omega0 = R/L.

    At that frequency, the phase shift is -45 degrees and the amplitude is
    down by 1/sqrt(2) (-3 dB) and the power dissipated in the resistor falls
    to half of its DC value.

    If we're using the series LR as a lowpass filter, that's the frequency
    that divides the passband, where the signal mostly gets through, from
    the stopband, where it mostly doesn't.

    So when we think in the time domain, a 1-ohm/1-henry LR circuit responds
    in about a second, whereas in the frequency domain, its bandwidth rolls
    off at omega = 1, i.e. at 1/(2 pi) Hz.

    With sinusoidal waveforms, we can think of 1 second corresponding to 1
    radian per second, whereas with pulses, a 1 second pulse has a 1-Hz-wide spectrum (counting negative frequencies).

    Thing is, a sine wave varies smoothly and goes through a much more
    complicated evolution (positive to negative and back) within a cycle, so
    it just takes longer, by a factor that turns out to be 2*pi.

    Cheers

    Phil Hobbs


    (*) Kipling, "How the Rhinoceros got his skin"

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to All on Sun Jun 30 07:38:19 2024
    On Sun, 30 Jun 2024 14:23:24 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    On Sun, 30 Jun 2024 06:05:41 -0700, john larkin
    <jlarkin_highland_tech> wrote:

    On Sun, 30 Jun 2024 08:44:34 +0100, Cursitor Doom <cd@notformail.com> >>wrote:

    Gentlemen,

    For more decades than I care to remember, I've been using formulae
    such as Xc= 1/2pifL, Xl=2pifC, Fo=1/2pisqrtLC and such like without
    even giving a thought as to how omega gets involved in so many aspects
    of RF. BTW, that's a lower-case, small omega meaning >>>2*pi*the-frequency-of-interest rather than the large Omega which is >>>already reserved for Ohms. How does it keep cropping up? What's so >>>special about the constant 6.283 and from what is it derived?
    Just curious...

    2 * pi.

    If a thing 1 unit in radius rotates one time per second, its
    circumference is 2pi so its rim velocity is 2pi/second.

    A capacitor current depends on the rate of change of the voltage.

    I = CV/T

    A 1 volt peak 1 Hz sine wave has its max rate of change at the zero >>crossing, and that rate is 2pi volts/second. So 1 farad driven with a
    1 Hz 1 volt peak sine wave has a peak current of 2pi amps.

    You can Spice all that to get a feel for things.

    Thanks, John. This is the fundamental stuff I just overlook since the
    need for it so rarely crops up. It's easier to take an abstraction
    level higher and lose all the vital detail in the process.

    It's good to understand the basics, but I mostly use Spice these days,
    even for simple things like voltage dividers.

    You're up early today. Off to church are we?

    No, I just woke up early with a zillion ideas. That happens some
    times.

    Today is San Francisco Pride Day (Dikes on Bikes and such) so it's a
    good day to stay close to home. Traffic and parking and everything
    will be a nightmare.

    https://sfpride.org/parade

    https://www.dropbox.com/scl/fi/j698pjo7jxm152zuzu4dx/Pink_Triangle.jpg?rlkey=n4xinzzm39bms9w04syb7egkx&raw=1

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to Phil Hobbs on Sun Jun 30 16:38:40 2024
    On Sun, 30 Jun 2024 13:51:42 -0000 (UTC), Phil Hobbs wrote:

    Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
    On 2024-06-30 03:44, Cursitor Doom wrote:
    Gentlemen,

    For more decades than I care to remember, I've been using formulae
    such as Xc= 1/2pifL, Xl=2pifC, Fo=1/2pisqrtLC and such like without
    even giving a thought as to how omega gets involved in so many aspects
    of RF. BTW, that's a lower-case, small omega meaning
    2*pi*the-frequency-of-interest rather than the large Omega which is
    already reserved for Ohms. How does it keep cropping up? What's so
    special about the constant 6.283 and from what is it derived?
    Just curious...


    As an old colleague of mine from grad school would say, "It just comes
    out in the math." ;)

    The 2*pi factor comes from the time domain / frequency domain
    conversion, and the basic behavior of linear differential equations
    with constant coefficients. (That's magic.(*)) For now we'll just talk
    about LR circuits and pulses.

    A 1-second pulse (time domain) has an equivalent width of 1 Hz
    (frequency domain, including negative frequencies). That's pretty
    intuitive, and shows that seconds and cycles per second are in some
    sense the same 'size'. The two scale inversely, e.g. a 1-ms pulse has
    an equivalent width of 1 kHz, also pretty intuitive. (Equivalent width
    is the mathematical quantity for which this 1-Hz/1-s inverse relation
    holds exactly, independent of the shape of the waveform.)

    Moving gently towards the frequency domain, we have the ideas of
    resistance and reactance. Resistance is defined by

    V = IR, (1)

    independent of both time and frequency. Actual resistors generally
    behave very much that way, over some reasonable range of frequencies
    and power levels. Either V or I can be taken as the independent
    variable, i.e. the one corresponding to the dial setting on the power
    supply, and the equation gives you the other (dependent) variable.

    A 1-Hz sine wave of unit amplitude at frequency f is given by

    I = sin(2 pi f t), (2)

    and the reactance of an inductance L is

    X = 2 pi f L. (3)

    The reactance is analogous to resistance, except that since inductance
    couples to dI/dt rather than I. From the definition of inductance,

    V = L dI/dt. (4)

    Plugging (2) into (4), you get

    V = L dI/dt = L * (2 pi f) cos(2 pi f t) = X_L cos(2 pi f t), (5)

    where X_L is the inductive reactance.

    We see that the voltage dropped by the inductance is phase shifted by
    1/4 cycle. Since the cosine reaches its peak at 0, where the current
    (the independent variable) is just going positive, we can say that the
    voltage waveform is _advanced_ by a quarter cycle, i.e. that the
    voltage is doing what the imposed current was doing a quarter cycle
    previously. (This seems like a fine point, but it's crucial to keeping
    the sign of the phase shift right, especially when you're a
    physics/engineering amphibian like me--the two disciplines use opposite
    sign conventions.)

    Besides the phase shift, the voltage across the inductance has an extra
    factor of 2 pi f. This is often written as a Greek lowercase omega,
    which for all you slipshod HTML-mode types is &omega; = 2&pi;f.

    Writing the sine wave as

    I = sin(&omega;t) (6)

    is faster, but the factor of 2 pi in amplitude keeps coming up, which
    it inescapably must, and it doesn't even really simplify the math much.

    For instance, if we apply a 1-V step function across a series RL with a
    time constant

    tau = L/R = 1 second, (7)

    the voltage on the resistor is

    V = 1-exp(-t). (8)

    In the frequency domain, the phase shift makes things a bit more
    complicated. If we use our nice real-valued sinusoidal current
    waveform (6) that we can see on a scope, then (after a small flurry of
    math), the voltage on the resistor comes out as

    V = sin(t - arctan(omega L/R)) / sqrt(1 + (omega L / R)**2). (9)

    This is because sines and cosines actually are sums of components of
    both positive and negative frequency, and which don't behave the same
    way when you differentiate them:

    sin(omega t) = 1/2 * (exp(j omega t) - exp(-j omega t)) (10)

    and

    cos(omega t) = 1/2 * (exp(j omega t) + exp(-j omega t)). (11)

    By switching to complex notation, and making a gentlemen's agreement to
    take the real part of everything before we start predicting actual
    measurable quantities, the math gets much simpler. Our sinusoidal
    input voltage becomes

    Vin = exp(j omega t) (12)

    and the voltage across the resistor is just the voltage divider thing:

    V/Vin = R / (R + j omega L). (13)

    At low frequencies, the resistance dominates and the inductance doesn't
    do anything much, just a small phase shift

    theta ~= - j omega L/R.

    At high frequencies, the inductance dominates. In the middle, the two
    effects become comparable at a frequency

    omega0 = R/L.

    At that frequency, the phase shift is -45 degrees and the amplitude is
    down by 1/sqrt(2) (-3 dB) and the power dissipated in the resistor
    falls to half of its DC value.

    If we're using the series LR as a lowpass filter, that's the frequency
    that divides the passband, where the signal mostly gets through, from
    the stopband, where it mostly doesn't.

    So when we think in the time domain, a 1-ohm/1-henry LR circuit
    responds in about a second, whereas in the frequency domain, its
    bandwidth rolls off at omega = 1, i.e. at 1/(2 pi) Hz.

    With sinusoidal waveforms, we can think of 1 second corresponding to 1
    radian per second, whereas with pulses, a 1 second pulse has a
    1-Hz-wide spectrum (counting negative frequencies).

    Thing is, a sine wave varies smoothly and goes through a much more
    complicated evolution (positive to negative and back) within a cycle,
    so it just takes longer, by a factor that turns out to be 2*pi.

    Cheers

    Phil Hobbs


    (*) Kipling, "How the Rhinoceros got his skin"


    Belay that last bit—it’s exactly backwards. I’ll fix it when I get back from church.

    Cheers

    Phil Hobbs

    Jeez, Phil. That's not just a follow-up, it's practically a treatise!
    Thanks for taking all that trouble. It's going to take quite some
    digesting!

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to john larkin on Sun Jun 30 16:45:05 2024
    On Sun, 30 Jun 2024 07:38:19 -0700, john larkin wrote:

    On Sun, 30 Jun 2024 14:23:24 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    On Sun, 30 Jun 2024 06:05:41 -0700, john larkin <jlarkin_highland_tech> >>wrote:

    On Sun, 30 Jun 2024 08:44:34 +0100, Cursitor Doom <cd@notformail.com> >>>wrote:

    Gentlemen,

    For more decades than I care to remember, I've been using formulae
    such as Xc= 1/2pifL, Xl=2pifC, Fo=1/2pisqrtLC and such like without >>>>even giving a thought as to how omega gets involved in so many aspects >>>>of RF. BTW, that's a lower-case, small omega meaning >>>>2*pi*the-frequency-of-interest rather than the large Omega which is >>>>already reserved for Ohms. How does it keep cropping up? What's so >>>>special about the constant 6.283 and from what is it derived?
    Just curious...

    2 * pi.

    If a thing 1 unit in radius rotates one time per second, its >>>circumference is 2pi so its rim velocity is 2pi/second.

    A capacitor current depends on the rate of change of the voltage.

    I = CV/T

    A 1 volt peak 1 Hz sine wave has its max rate of change at the zero >>>crossing, and that rate is 2pi volts/second. So 1 farad driven with a 1 >>>Hz 1 volt peak sine wave has a peak current of 2pi amps.

    You can Spice all that to get a feel for things.

    Thanks, John. This is the fundamental stuff I just overlook since the
    need for it so rarely crops up. It's easier to take an abstraction level >>higher and lose all the vital detail in the process.

    It's good to understand the basics, but I mostly use Spice these days,
    even for simple things like voltage dividers.

    You're up early today. Off to church are we?

    No, I just woke up early with a zillion ideas. That happens some times.

    Today is San Francisco Pride Day (Dikes on Bikes and such) so it's a
    good day to stay close to home. Traffic and parking and everything will
    be a nightmare.

    https://sfpride.org/parade

    https://www.dropbox.com/scl/fi/j698pjo7jxm152zuzu4dx/Pink_Triangle.jpg?
    rlkey=n4xinzzm39bms9w04syb7egkx&raw=1

    I went to one of those once in Berlin when I lived there. God almighty!
    I've never seen such a complete and utter freak show in my entire life. I
    just stood there gaping open-mouthed at the procession. It must have been pretty obvious to any of those weirdos on the floats that I wasn't there
    to celebrate them! I just find it bizarre that parents actually take their
    kids to see this sort of thing and they're all waving their rainbow flags
    and whatnot. No kids of mine would be allowed within a million miles of an event like that. No wonder the God-fearing folks reckon the world's going
    to hell in a handbasket. :(

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From ehsjr@21:1/5 to Cursitor Doom on Sun Jun 30 16:35:34 2024
    On 6/30/2024 3:44 AM, Cursitor Doom wrote:
    Gentlemen,

    For more decades than I care to remember, I've been using formulae
    such as Xc= 1/2pifL, Xl=2pifC, Fo=1/2pisqrtLC and such like without
    even giving a thought as to how omega gets involved in so many aspects
    of RF. BTW, that's a lower-case, small omega meaning 2*pi*the-frequency-of-interest rather than the large Omega which is
    already reserved for Ohms. How does it keep cropping up? What's so
    special about the constant 6.283 and from what is it derived?
    Just curious...

    You've had a number of answers - but not really answering at
    the "gut" level. Why is 2 pi so important - how does omega
    get involved in so many aspects of RF?

    Every one of the formulas you mentioned has to do with frequency.
    The unit of measurement for that is Hertz which is CYCLE(s) per
    second.
    A cycle's length is 360 degrees regardless of frequency.
    A CIRCLE's length is 360 degrees regardless of frequency.
    A circle's length is also 2*pi*r regardless of frequency.
    Therefore a CYCLE's length (a.k.a wavelength a.k.a. omega)
    is also 2*pi*r long.

    So 2*pi is used in the conversion between the number of
    degrees (time) and distance (length displacement) or
    "How much happened ?" (length displacement)
    "and how long did it take?" time (frequency).

    That's what some call the "gut level" understanding aas
    to why 2*pi appears so often. If you use the math a lot
    over time it becomes less mysterious - if that's the right
    term. I guess you develop an intuitive understanding or
    something like that.

    Ed

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to ehsjr on Sun Jun 30 22:44:20 2024
    On Sun, 30 Jun 2024 16:35:34 -0400, ehsjr wrote:

    On 6/30/2024 3:44 AM, Cursitor Doom wrote:
    Gentlemen,

    For more decades than I care to remember, I've been using formulae such
    as Xc= 1/2pifL, Xl=2pifC, Fo=1/2pisqrtLC and such like without even
    giving a thought as to how omega gets involved in so many aspects of
    RF. BTW, that's a lower-case, small omega meaning
    2*pi*the-frequency-of-interest rather than the large Omega which is
    already reserved for Ohms. How does it keep cropping up? What's so
    special about the constant 6.283 and from what is it derived?
    Just curious...

    You've had a number of answers - but not really answering at the "gut"
    level. Why is 2 pi so important - how does omega get involved in so
    many aspects of RF?

    Every one of the formulas you mentioned has to do with frequency.
    The unit of measurement for that is Hertz which is CYCLE(s) per second.
    A cycle's length is 360 degrees regardless of frequency.
    A CIRCLE's length is 360 degrees regardless of frequency.
    A circle's length is also 2*pi*r regardless of frequency. Therefore a
    CYCLE's length (a.k.a wavelength a.k.a. omega)
    is also 2*pi*r long.

    So 2*pi is used in the conversion between the number of degrees (time)
    and distance (length displacement) or "How much happened ?" (length displacement)
    "and how long did it take?" time (frequency).

    That's what some call the "gut level" understanding aas to why 2*pi
    appears so often. If you use the math a lot over time it becomes less mysterious - if that's the right term. I guess you develop an intuitive understanding or something like that.

    There's something about electronics and its associated mathematics that
    I've always found challenging to be honest. Many years ago when I studied medicine and then law I didn't have to do any real work at all to speak
    of. I just absorbed those subjects easily without even trying. I was often baffled as to why so many students struggled with the topics in those
    subjects and why they clearly had to work so hard for so long to keep up
    with the class. I'd skip lectures and assignments with gay abandon but
    still get top marks. Not so with the hard sciences! Now I can finally
    empathise with my contemporaries back in those days who had to really make
    a serious effort to grasp the principles and who just about scraped
    through. They would never go on to excel in those fields just as I have
    never and will never excel at electronics. Still, no one can be
    outstanding at everything in today's world and the days of the true
    polymaths are long gone.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to Phil Hobbs on Sun Jun 30 21:17:53 2024
    On 2024-06-30 09:51, Phil Hobbs wrote:
    Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
    On 2024-06-30 03:44, Cursitor Doom wrote:
    Gentlemen,

    For more decades than I care to remember, I've been using formulae
    such as Xc= 1/2pifL, Xl=2pifC, Fo=1/2pisqrtLC and such like without
    even giving a thought as to how omega gets involved in so many aspects
    of RF. BTW, that's a lower-case, small omega meaning
    2*pi*the-frequency-of-interest rather than the large Omega which is
    already reserved for Ohms. How does it keep cropping up? What's so
    special about the constant 6.283 and from what is it derived?
    Just curious...


    Okay, once more with feelin'. Hopefully this is a bit more coherent throughout.

    As an old colleague of mine from grad school would say, "It just comes
    out in the math." ;)

    The 2*pi factor comes from the time domain / frequency domain
    conversion, and the basic behavior of linear differential equations with constant coefficients. (That's magic.(*)) Pardon my waving my arms a
    bit--that way we can avoid DEs and Fourier integrals. Here goes.

    A 1-second pulse (time domain) has an equivalent width of 1 Hz
    (frequency domain, including negative frequencies). That's pretty
    intuitive, and shows that seconds and cycles per second are in some
    sense the same 'size'. The two scale inversely, e.g. a 1-ms pulse has
    an equivalent width of 1 kHz, also pretty intuitive.

    Moving gently towards the frequency domain, we have the ideas of
    resistance and reactance. Resistance is defined by

    V = IR, (1)

    independent of both time and frequency. Actual resistors generally
    behave very much that way, over some reasonable range of frequencies and
    power levels. Either V or I can be taken as the independent variable,
    i.e. the one corresponding to the dial setting on the power supply, and
    the equation gives you the other (dependent) variable.

    A 1-Hz sine wave of unit amplitude at frequency f is given by

    I = sin(2 pi f t), (2)

    and the reactance of an inductance L is

    X = 2 pi f L. (3)

    The reactance is analogous to resistance, except that inductance couples
    to dI/dt rather than I. This comes right out of the definition of
    inductance,

    V = L dI/dt. (4)

    Plugging (2) into (4), you get

    V = L dI/dt = L * (2 pi f) cos(2 pi f t). (5)

    We see that the voltage dropped by the inductance is phase shifted by
    1/4 cycle.

    Since the cosine reaches its peak at 0, where the current (the
    independent variable) is just going positive, we can say that the
    voltage waveform is _advanced_ by a quarter cycle, i.e. that the voltage
    is doing what the imposed current was doing a quarter cycle previously. (**)

    Besides the phase shift, the voltage across the inductance has an extra
    factor of 2 pi f. This is often written as a Greek lowercase omega,
    which for all you supercool HTML-mode types is &omega; = 2&pi;f. The
    factor &omega;L comes in exactly the same way as resistance, except for
    the frequency dependence and quarter-cycle phase shift, so it's called _reactance_, as noted above.

    Writing the sine wave as

    I = sin(&omega;t) (6)

    is faster, but the factor of 2 pi in amplitude keeps coming up, which it inescapably must, and it doesn't even really simplify the math much.
    (Once you get to Fourier transforms, keeping the 2*pi explicit saves
    many blunders, it turns out.)

    For instance, if we apply a 1-V step function across a series RL with a
    time constant

    tau = L/R = 1 second, (7)

    the voltage on the resistor is

    V = 1-exp(-t). (8)

    This rises from 0 to ~0.63 in 1s, 0.9 in 2.3s, and 0.95 in 3.0s.

    In the frequency domain, the phase shift makes things a bit more
    complicated. If we use our nice real-valued sinusoidal current waveform
    (6) that we can see on a scope, then (after a small flurry of math), the voltage on the resistor comes out as

    V = sin(t - arctan(omega L/R)) / sqrt(1 + (omega L / R)**2). (9)

    This is because sines and cosines actually are sums of components of
    both positive and negative frequency, which don't behave the same way
    when you differentiate them:

    sin(omega t) = 1/2 * (exp(j omega t) - exp(-j omega t)) (10)

    and

    cos(omega t) = 1/2 * (exp(j omega t) + exp(-j omega t)). (***) (11)

    By switching to complex notation and making a gentlemen's agreement to
    take the real part of everything before we start predicting actual
    measurable quantities, the math gets much simpler. Our sinusoidal input voltage becomes

    Vin = exp(j omega t) (12)

    and the voltage across the resistor is just the voltage divider thing:

    V/Vin = R / (R + j omega L). (13)

    At low frequencies, the resistance dominates and the inductance doesn't
    do anything much, just a small linear phase shift with frequency

    theta ~= - j omega L/R. (14)

    At high frequencies, the inductance dominates. In the middle, the two
    effects become comparable at a frequency

    omega0 = R/L.

    At that frequency, the phase shift is -45 degrees and the amplitude is
    down by 1/sqrt(2) (-3 dB) and the power dissipated in the resistance
    falls to half of its DC value.

    If we're using the series LR as a lowpass filter, omega_0 is the
    frequency that divides the passband, where the signal mostly gets
    through, from the stopband, where it mostly doesn't. It's worth noting
    that if you extrapolate the low-frequency straight line (14), it passes
    through 1 radian at omega_0 as well.

    So when we think in the time domain, a 1-ohm/1-henry LR circuit responds
    in about a second, whereas in the frequency domain, its bandwidth rolls
    off at omega = 1, i.e. at 1/(2 pi) Hz.

    <Correcting brain fart due to trying to do too many things at once>

    Thus with sinusoidal waveforms, we can think of 1 second corresponding
    to 1 radian per second, whereas with pulses, a 1 second pulse has a
    1-Hz-wide spectrum (counting negative frequencies). Weird, right? What's
    up with that?

    One way of understanding it is that a square pulse has a lot more high-frequency components than a sine wave. To make our 1-s decaying exponential resemble a 1-s pulse a bit more closely, we need it to start
    from 0 and go back to 0. A first try would be making it symmetric.
    That costs you in bandwidth, because going up takes as long as going
    down, so you have to speed up the time constant.

    If we speed it up by a factor of 2, the amplitude reaches 1-exp(-1) ~=
    0.63V before starting down again. By the inverse scaling relation, that doubles the bandwidth, getting us to 2 rad/s. To make it a bit more square-looking, we could speed it up some more. Getting up to 90% of
    full amplitude takes 2.2 time constants, which notionally takes us to
    4.4 rad/s.

    Someplace in there we have to start using Fourier integrals, because
    otherwise we'll start thinking that a perfectly square pulse has
    infinite bandwidth, which it doesn't. To avoid that, perhaps you'll
    take my word that some more math will show that an actually rectangular
    pulse gets you up to 2*pi rad/s, i.e. 1 Hz.

    Cheers

    Phil Hobbs

    (*) Rudyard Kipling, "How the rhinoceros got his skin", in *Just So
    Stories*, Macmillan, 1902.

    (**) This seems like a fine point, but it's crucial to keeping the sign
    of the phase shift right, especially when you're a physics/engineering amphibian like me--in physics an advance is a negative phase shift,
    whereas in EE it's positive, owing to different sign conventions.

    (***) Here I've adopted the EE sign convention, and so am using 'j' for
    the corresponding square root of -1. I use 'i' in physics and math discussions, and that helps keeps everything straight.

    --
    Dr Philip C D Hobbs
    Principal Consultant
    ElectroOptical Innovations LLC / Hobbs ElectroOptics
    Optics, Electro-optics, Photonics, Analog Electronics
    Briarcliff Manor NY 10510

    http://electrooptical.net
    http://hobbs-eo.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Bill Sloman@21:1/5 to Cursitor Doom on Mon Jul 1 13:04:17 2024
    On 1/07/2024 2:45 am, Cursitor Doom wrote:
    On Sun, 30 Jun 2024 07:38:19 -0700, john larkin wrote:

    On Sun, 30 Jun 2024 14:23:24 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    On Sun, 30 Jun 2024 06:05:41 -0700, john larkin <jlarkin_highland_tech>
    wrote:

    On Sun, 30 Jun 2024 08:44:34 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    <snip>

    Today is San Francisco Pride Day (Dikes on Bikes and such) so it's a
    good day to stay close to home. Traffic and parking and everything will
    be a nightmare.

    https://sfpride.org/parade

    https://www.dropbox.com/scl/fi/j698pjo7jxm152zuzu4dx/Pink_Triangle.jpg?
    rlkey=n4xinzzm39bms9w04syb7egkx&raw=1

    I went to one of those once in Berlin when I lived there. God almighty!
    I've never seen such a complete and utter freak show in my entire life. I just stood there gaping open-mouthed at the procession. It must have been pretty obvious to any of those weirdos on the floats that I wasn't there
    to celebrate them! I just find it bizarre that parents actually take their kids to see this sort of thing and they're all waving their rainbow flags
    and whatnot. No kids of mine would be allowed within a million miles of an event like that. No wonder the God-fearing folks reckon the world's going
    to hell in a handbasket. :(

    Far from it. In Sydney we have a gay pride march down Oxford Street
    every year, which I've never watched (though it does show up on the TV
    news every year). A couple of my neighbours decorate a truck for the
    procession just outside the building ever year and I say hello to them
    if I go past them while they are working on it.

    It keeps them happy, and NSW is a much better place now that the cops
    have been persuaded that gay-bashing isn't one of their duties, and now
    have a contingent marching in the procession.

    I'm a bit surprised that freaks like you, with your unbounded passion
    for fatuous conspiracy theories, don't get together in the same sort of
    way to show off your unique talents.

    Donald Trump's MAGA rallies probably qualify as much the same sort of celebration of rampant irrationality, but they don't get reported that
    way - or haven't so far.

    --
    Bill Sloman, Sydney

    --
    This email has been checked for viruses by Norton antivirus software. www.norton.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From bitrex@21:1/5 to Cursitor Doom on Mon Jul 1 13:39:51 2024
    On 6/30/2024 12:45 PM, Cursitor Doom wrote:
    On Sun, 30 Jun 2024 07:38:19 -0700, john larkin wrote:

    On Sun, 30 Jun 2024 14:23:24 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    On Sun, 30 Jun 2024 06:05:41 -0700, john larkin <jlarkin_highland_tech>
    wrote:

    On Sun, 30 Jun 2024 08:44:34 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    Gentlemen,

    For more decades than I care to remember, I've been using formulae
    such as Xc= 1/2pifL, Xl=2pifC, Fo=1/2pisqrtLC and such like without
    even giving a thought as to how omega gets involved in so many aspects >>>>> of RF. BTW, that's a lower-case, small omega meaning
    2*pi*the-frequency-of-interest rather than the large Omega which is
    already reserved for Ohms. How does it keep cropping up? What's so
    special about the constant 6.283 and from what is it derived?
    Just curious...

    2 * pi.

    If a thing 1 unit in radius rotates one time per second, its
    circumference is 2pi so its rim velocity is 2pi/second.

    A capacitor current depends on the rate of change of the voltage.

    I = CV/T

    A 1 volt peak 1 Hz sine wave has its max rate of change at the zero
    crossing, and that rate is 2pi volts/second. So 1 farad driven with a 1 >>>> Hz 1 volt peak sine wave has a peak current of 2pi amps.

    You can Spice all that to get a feel for things.

    Thanks, John. This is the fundamental stuff I just overlook since the
    need for it so rarely crops up. It's easier to take an abstraction level >>> higher and lose all the vital detail in the process.

    It's good to understand the basics, but I mostly use Spice these days,
    even for simple things like voltage dividers.

    You're up early today. Off to church are we?

    No, I just woke up early with a zillion ideas. That happens some times.

    Today is San Francisco Pride Day (Dikes on Bikes and such) so it's a
    good day to stay close to home. Traffic and parking and everything will
    be a nightmare.

    https://sfpride.org/parade

    https://www.dropbox.com/scl/fi/j698pjo7jxm152zuzu4dx/Pink_Triangle.jpg?
    rlkey=n4xinzzm39bms9w04syb7egkx&raw=1

    I went to one of those once in Berlin when I lived there. God almighty!
    I've never seen such a complete and utter freak show in my entire life. I just stood there gaping open-mouthed at the procession. It must have been pretty obvious to any of those weirdos on the floats that I wasn't there
    to celebrate them! I just find it bizarre that parents actually take their kids to see this sort of thing and they're all waving their rainbow flags
    and whatnot. No kids of mine would be allowed within a million miles of an event like that. No wonder the God-fearing folks reckon the world's going
    to hell in a handbasket. :(

    Could always move to places that tolerate that sort of stuff. Saudi
    Arabia. Moscow. Abilene, Texas. Lots of options.

    But Mr. Larkin seems to prefer it in San Fran and you seem to prefer
    flitting about western Europe, interesting.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to bitrex on Mon Jul 1 17:49:00 2024
    On Mon, 1 Jul 2024 13:39:51 -0400, bitrex wrote:

    On 6/30/2024 12:45 PM, Cursitor Doom wrote:
    On Sun, 30 Jun 2024 07:38:19 -0700, john larkin wrote:

    On Sun, 30 Jun 2024 14:23:24 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    On Sun, 30 Jun 2024 06:05:41 -0700, john larkin
    <jlarkin_highland_tech> wrote:

    On Sun, 30 Jun 2024 08:44:34 +0100, Cursitor Doom
    <cd@notformail.com> wrote:

    Gentlemen,

    For more decades than I care to remember, I've been using formulae >>>>>> such as Xc= 1/2pifL, Xl=2pifC, Fo=1/2pisqrtLC and such like without >>>>>> even giving a thought as to how omega gets involved in so many
    aspects of RF. BTW, that's a lower-case, small omega meaning
    2*pi*the-frequency-of-interest rather than the large Omega which is >>>>>> already reserved for Ohms. How does it keep cropping up? What's so >>>>>> special about the constant 6.283 and from what is it derived?
    Just curious...

    2 * pi.

    If a thing 1 unit in radius rotates one time per second, its
    circumference is 2pi so its rim velocity is 2pi/second.

    A capacitor current depends on the rate of change of the voltage.

    I = CV/T

    A 1 volt peak 1 Hz sine wave has its max rate of change at the zero >>>>> crossing, and that rate is 2pi volts/second. So 1 farad driven with
    a 1 Hz 1 volt peak sine wave has a peak current of 2pi amps.

    You can Spice all that to get a feel for things.

    Thanks, John. This is the fundamental stuff I just overlook since the
    need for it so rarely crops up. It's easier to take an abstraction
    level higher and lose all the vital detail in the process.

    It's good to understand the basics, but I mostly use Spice these days,
    even for simple things like voltage dividers.

    You're up early today. Off to church are we?

    No, I just woke up early with a zillion ideas. That happens some
    times.

    Today is San Francisco Pride Day (Dikes on Bikes and such) so it's a
    good day to stay close to home. Traffic and parking and everything
    will be a nightmare.

    https://sfpride.org/parade

    https://www.dropbox.com/scl/fi/j698pjo7jxm152zuzu4dx/
    Pink_Triangle.jpg?
    rlkey=n4xinzzm39bms9w04syb7egkx&raw=1

    I went to one of those once in Berlin when I lived there. God almighty!
    I've never seen such a complete and utter freak show in my entire life.
    I just stood there gaping open-mouthed at the procession. It must have
    been pretty obvious to any of those weirdos on the floats that I wasn't
    there to celebrate them! I just find it bizarre that parents actually
    take their kids to see this sort of thing and they're all waving their
    rainbow flags and whatnot. No kids of mine would be allowed within a
    million miles of an event like that. No wonder the God-fearing folks
    reckon the world's going to hell in a handbasket. :(

    Could always move to places that tolerate that sort of stuff. Saudi
    Arabia. Moscow. Abilene, Texas. Lots of options.

    But Mr. Larkin seems to prefer it in San Fran and you seem to prefer
    flitting about western Europe, interesting.

    Well, I did warn John about moving to SF many years ago as I could tell
    the way it was going, but he went ahead anyway and seems to have an
    uncanny ability to only notice the nice side of the place (mainly by not venturing downtown, it seems).

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to Phil Hobbs on Mon Jul 1 17:52:17 2024
    On Sun, 30 Jun 2024 21:17:53 -0400, Phil Hobbs wrote:

    On 2024-06-30 09:51, Phil Hobbs wrote:
    Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:
    On 2024-06-30 03:44, Cursitor Doom wrote:
    Gentlemen,

    For more decades than I care to remember, I've been using formulae
    such as Xc= 1/2pifL, Xl=2pifC, Fo=1/2pisqrtLC and such like without
    even giving a thought as to how omega gets involved in so many
    aspects of RF. BTW, that's a lower-case, small omega meaning
    2*pi*the-frequency-of-interest rather than the large Omega which is
    already reserved for Ohms. How does it keep cropping up? What's so
    special about the constant 6.283 and from what is it derived?
    Just curious...


    Okay, once more with feelin'. Hopefully this is a bit more coherent throughout.

    As an old colleague of mine from grad school would say, "It just comes
    out in the math." ;)

    The 2*pi factor comes from the time domain / frequency domain
    conversion, and the basic behavior of linear differential equations with constant coefficients. (That's magic.(*)) Pardon my waving my arms a bit--that way we can avoid DEs and Fourier integrals. Here goes.

    A 1-second pulse (time domain) has an equivalent width of 1 Hz
    (frequency domain, including negative frequencies). That's pretty
    intuitive, and shows that seconds and cycles per second are in some
    sense the same 'size'. The two scale inversely, e.g. a 1-ms pulse has
    an equivalent width of 1 kHz, also pretty intuitive.

    Moving gently towards the frequency domain, we have the ideas of
    resistance and reactance. Resistance is defined by

    V = IR, (1)

    independent of both time and frequency. Actual resistors generally
    behave very much that way, over some reasonable range of frequencies and power levels. Either V or I can be taken as the independent variable,
    i.e. the one corresponding to the dial setting on the power supply, and
    the equation gives you the other (dependent) variable.

    A 1-Hz sine wave of unit amplitude at frequency f is given by

    I = sin(2 pi f t), (2)

    and the reactance of an inductance L is

    X = 2 pi f L. (3)

    The reactance is analogous to resistance, except that inductance couples
    to dI/dt rather than I. This comes right out of the definition of inductance,

    V = L dI/dt. (4)

    Plugging (2) into (4), you get

    V = L dI/dt = L * (2 pi f) cos(2 pi f t). (5)

    We see that the voltage dropped by the inductance is phase shifted by
    1/4 cycle.

    Since the cosine reaches its peak at 0, where the current (the
    independent variable) is just going positive, we can say that the
    voltage waveform is _advanced_ by a quarter cycle, i.e. that the voltage
    is doing what the imposed current was doing a quarter cycle previously.
    (**)

    Besides the phase shift, the voltage across the inductance has an extra factor of 2 pi f. This is often written as a Greek lowercase omega,
    which for all you supercool HTML-mode types is &omega; = 2&pi;f. The
    factor &omega;L comes in exactly the same way as resistance, except for
    the frequency dependence and quarter-cycle phase shift, so it's called _reactance_, as noted above.

    Writing the sine wave as

    I = sin(&omega;t) (6)

    is faster, but the factor of 2 pi in amplitude keeps coming up, which it inescapably must, and it doesn't even really simplify the math much.
    (Once you get to Fourier transforms, keeping the 2*pi explicit saves
    many blunders, it turns out.)

    For instance, if we apply a 1-V step function across a series RL with a
    time constant

    tau = L/R = 1 second, (7)

    the voltage on the resistor is

    V = 1-exp(-t). (8)

    This rises from 0 to ~0.63 in 1s, 0.9 in 2.3s, and 0.95 in 3.0s.

    In the frequency domain, the phase shift makes things a bit more
    complicated. If we use our nice real-valued sinusoidal current waveform
    (6) that we can see on a scope, then (after a small flurry of math), the voltage on the resistor comes out as

    V = sin(t - arctan(omega L/R)) / sqrt(1 + (omega L / R)**2). (9)

    This is because sines and cosines actually are sums of components of
    both positive and negative frequency, which don't behave the same way
    when you differentiate them:

    sin(omega t) = 1/2 * (exp(j omega t) - exp(-j omega t)) (10)

    and

    cos(omega t) = 1/2 * (exp(j omega t) + exp(-j omega t)). (***) (11)

    By switching to complex notation and making a gentlemen's agreement to
    take the real part of everything before we start predicting actual
    measurable quantities, the math gets much simpler. Our sinusoidal input voltage becomes

    Vin = exp(j omega t) (12)

    and the voltage across the resistor is just the voltage divider thing:

    V/Vin = R / (R + j omega L). (13)

    At low frequencies, the resistance dominates and the inductance doesn't
    do anything much, just a small linear phase shift with frequency

    theta ~= - j omega L/R. (14)

    At high frequencies, the inductance dominates. In the middle, the two effects become comparable at a frequency

    omega0 = R/L.

    At that frequency, the phase shift is -45 degrees and the amplitude is
    down by 1/sqrt(2) (-3 dB) and the power dissipated in the resistance
    falls to half of its DC value.

    If we're using the series LR as a lowpass filter, omega_0 is the
    frequency that divides the passband, where the signal mostly gets
    through, from the stopband, where it mostly doesn't. It's worth noting
    that if you extrapolate the low-frequency straight line (14), it passes through 1 radian at omega_0 as well.

    So when we think in the time domain, a 1-ohm/1-henry LR circuit responds
    in about a second, whereas in the frequency domain, its bandwidth rolls
    off at omega = 1, i.e. at 1/(2 pi) Hz.

    <Correcting brain fart due to trying to do too many things at once>

    Thus with sinusoidal waveforms, we can think of 1 second corresponding
    to 1 radian per second, whereas with pulses, a 1 second pulse has a
    1-Hz-wide spectrum (counting negative frequencies). Weird, right? What's
    up with that?

    One way of understanding it is that a square pulse has a lot more high-frequency components than a sine wave. To make our 1-s decaying exponential resemble a 1-s pulse a bit more closely, we need it to start
    from 0 and go back to 0. A first try would be making it symmetric.
    That costs you in bandwidth, because going up takes as long as going
    down, so you have to speed up the time constant.

    If we speed it up by a factor of 2, the amplitude reaches 1-exp(-1) ~=
    0.63V before starting down again. By the inverse scaling relation, that doubles the bandwidth, getting us to 2 rad/s. To make it a bit more square-looking, we could speed it up some more. Getting up to 90% of
    full amplitude takes 2.2 time constants, which notionally takes us to
    4.4 rad/s.

    Someplace in there we have to start using Fourier integrals, because otherwise we'll start thinking that a perfectly square pulse has
    infinite bandwidth, which it doesn't. To avoid that, perhaps you'll
    take my word that some more math will show that an actually rectangular
    pulse gets you up to 2*pi rad/s, i.e. 1 Hz.

    Cheers

    Phil Hobbs

    (*) Rudyard Kipling, "How the rhinoceros got his skin", in *Just So
    Stories*, Macmillan, 1902.

    (**) This seems like a fine point, but it's crucial to keeping the sign
    of the phase shift right, especially when you're a physics/engineering amphibian like me--in physics an advance is a negative phase shift,
    whereas in EE it's positive, owing to different sign conventions.

    (***) Here I've adopted the EE sign convention, and so am using 'j' for
    the corresponding square root of -1. I use 'i' in physics and math discussions, and that helps keeps everything straight.

    Many thanks, Phil. I've printed this out as I have a funny feeling that
    despite your sterling attempts at simplifying things, I'm going to need to
    read it over and over and over again.....

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Don@21:1/5 to Cursitor Doom on Mon Jul 1 19:11:07 2024
    Cursitor Doom wrote:
    Gentlemen,

    For more decades than I care to remember, I've been using formulae
    such as Xc= 1/2pifL, Xl=2pifC, Fo=1/2pisqrtLC and such like without
    even giving a thought as to how omega gets involved in so many aspects
    of RF. BTW, that's a lower-case, small omega meaning 2*pi*the-frequency-of-interest rather than the large Omega which is
    already reserved for Ohms. How does it keep cropping up? What's so
    special about the constant 6.283 and from what is it derived?
    Just curious...

    A Surprising Collision Phenomenon
    <https://redd.it/1dh7jvt>

    ... It's because most people are only taught that Pi applies
    to circles, but it also applies to things that are periodic
    (like the weights in the video perfectly bouncing off each
    other and the wall).

    But to go deeper, why would something periodic have Pi
    showing up in it? Because the math we invented to explain
    periodic things is called Trigonometry. Turns out trigonometry
    is based on (here it comes) circles.

    So, just about anything that has some repeating aspect to it
    can be described with math that relates it to a circle, and
    that is why Pi shows up. ...

    Danke,

    --
    Don, KB7RPU, https://www.qsl.net/kb7rpu
    There was a young lady named Bright Whose speed was far faster than light;
    She set out one day In a relative way And returned on the previous night.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to cd999666@notformail.com on Mon Jul 1 16:30:42 2024
    On Mon, 1 Jul 2024 17:49:00 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:

    On Mon, 1 Jul 2024 13:39:51 -0400, bitrex wrote:

    On 6/30/2024 12:45 PM, Cursitor Doom wrote:
    On Sun, 30 Jun 2024 07:38:19 -0700, john larkin wrote:

    On Sun, 30 Jun 2024 14:23:24 +0100, Cursitor Doom <cd@notformail.com>
    wrote:

    On Sun, 30 Jun 2024 06:05:41 -0700, john larkin
    <jlarkin_highland_tech> wrote:

    On Sun, 30 Jun 2024 08:44:34 +0100, Cursitor Doom
    <cd@notformail.com> wrote:

    Gentlemen,

    For more decades than I care to remember, I've been using formulae >>>>>>> such as Xc= 1/2pifL, Xl=2pifC, Fo=1/2pisqrtLC and such like without >>>>>>> even giving a thought as to how omega gets involved in so many
    aspects of RF. BTW, that's a lower-case, small omega meaning
    2*pi*the-frequency-of-interest rather than the large Omega which is >>>>>>> already reserved for Ohms. How does it keep cropping up? What's so >>>>>>> special about the constant 6.283 and from what is it derived?
    Just curious...

    2 * pi.

    If a thing 1 unit in radius rotates one time per second, its
    circumference is 2pi so its rim velocity is 2pi/second.

    A capacitor current depends on the rate of change of the voltage.

    I = CV/T

    A 1 volt peak 1 Hz sine wave has its max rate of change at the zero >>>>>> crossing, and that rate is 2pi volts/second. So 1 farad driven with >>>>>> a 1 Hz 1 volt peak sine wave has a peak current of 2pi amps.

    You can Spice all that to get a feel for things.

    Thanks, John. This is the fundamental stuff I just overlook since the >>>>> need for it so rarely crops up. It's easier to take an abstraction
    level higher and lose all the vital detail in the process.

    It's good to understand the basics, but I mostly use Spice these days, >>>> even for simple things like voltage dividers.

    You're up early today. Off to church are we?

    No, I just woke up early with a zillion ideas. That happens some
    times.

    Today is San Francisco Pride Day (Dikes on Bikes and such) so it's a
    good day to stay close to home. Traffic and parking and everything
    will be a nightmare.

    https://sfpride.org/parade

    https://www.dropbox.com/scl/fi/j698pjo7jxm152zuzu4dx/
    Pink_Triangle.jpg?
    rlkey=n4xinzzm39bms9w04syb7egkx&raw=1

    I went to one of those once in Berlin when I lived there. God almighty!
    I've never seen such a complete and utter freak show in my entire life.
    I just stood there gaping open-mouthed at the procession. It must have
    been pretty obvious to any of those weirdos on the floats that I wasn't
    there to celebrate them! I just find it bizarre that parents actually
    take their kids to see this sort of thing and they're all waving their
    rainbow flags and whatnot. No kids of mine would be allowed within a
    million miles of an event like that. No wonder the God-fearing folks
    reckon the world's going to hell in a handbasket. :(

    Could always move to places that tolerate that sort of stuff. Saudi
    Arabia. Moscow. Abilene, Texas. Lots of options.

    But Mr. Larkin seems to prefer it in San Fran and you seem to prefer
    flitting about western Europe, interesting.

    Well, I did warn John about moving to SF many years ago as I could tell
    the way it was going, but he went ahead anyway and seems to have an
    uncanny ability to only notice the nice side of the place (mainly by not >venturing downtown, it seems).

    You warned me? What's your real name?

    When I decided to move to SF, my friends said "But it's full of gay
    guys" to which I replied "and lots of smart beautiful women."

    Do the math on that.

    Right, we avoid the tourist traps and homeless encampments. The hills
    separate SF into a collection of villages, with even different
    weather.

    It's a great place to be weird. People get it.

    But 2*pi is still 2*pi even here.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to All on Sat Jul 6 00:31:25 2024
    On Fri, 05 Jul 2024 00:33:31 +0100, JM <sunaecoNoSpam@gmail.com>
    wrote:

    On Sun, 30 Jun 2024 08:44:34 +0100, Cursitor Doom <cd@notformail.com> wrote:

    Gentlemen,

    For more decades than I care to remember, I've been using formulae
    such as Xc= 1/2pifL, Xl=2pifC, Fo=1/2pisqrtLC and such like without
    even giving a thought as to how omega gets involved in so many aspects
    of RF. BTW, that's a lower-case, small omega meaning >>2*pi*the-frequency-of-interest rather than the large Omega which is
    already reserved for Ohms. How does it keep cropping up? What's so
    special about the constant 6.283 and from what is it derived?
    Just curious...

    What you are really asking (but may not realise) is why do mathematicians measure an angle in radians. If you draw two straught lines from the origin of a circle to its edge, then the angle (in radians) between the lines is the arc length (length of
    the part of the circle circumference between the two lines) divided by the radius. So if a single line rotates one complete revolution it rotates 2.PI radians.

    One important thing to note is that if an angle x is measured in radians then the limit of sin(x)/x as x goes to 0 is 1. This leads to the derivative (wrt x) of sin(x) being equal to cos(x). *This is not true is x is not specified in radians*. (It
    also leads to simple series expansions of the trigonometric fuctions, to eulers formula etc.)

    When performing calculus it is thus easiest to do so if angles are measured in radians. For a signal of frequency f it's corresponding phasor representation will rotate by 2.PI.f.t radians in an interval t. This is where the 2.PI comes from in your
    calculations.

    For example for your inductor L the voltage across it and the current through it are related by e=L.di/dt. If the current i=I.sin(wt) (w in rad/s) then e=wLI.cos(wt). Thus the impedance e/i is wL cos(wt)/sin(wt) ie. it has a magnitude of wL (or 2.PI.f.
    L )and a phase angle of PI/2. And so forth.


    Another piece of the jigsaw. Many thanks indeed for that contribution.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Edward Rawde@21:1/5 to From what John has on Mon Jul 8 14:08:33 2024
    "john larkin" <jlarkin_highland_tech> wrote in message news:bge68jhpanmo6vs4j780am19vc6fh9ndfo@4ax.com...
    On Mon, 1 Jul 2024 17:49:00 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:

    On Mon, 1 Jul 2024 13:39:51 -0400, bitrex wrote:

    On 6/30/2024 12:45 PM, Cursitor Doom wrote:
    On Sun, 30 Jun 2024 07:38:19 -0700, john larkin wrote:

    On Sun, 30 Jun 2024 14:23:24 +0100, Cursitor Doom <cd@notformail.com> >>>>> wrote:

    On Sun, 30 Jun 2024 06:05:41 -0700, john larkin
    <jlarkin_highland_tech> wrote:

    On Sun, 30 Jun 2024 08:44:34 +0100, Cursitor Doom
    <cd@notformail.com> wrote:

    Gentlemen,
    ...

    Today is San Francisco Pride Day (Dikes on Bikes and such) so it's a >>>>> good day to stay close to home. Traffic and parking and everything
    will be a nightmare.

    https://sfpride.org/parade

    https://www.dropbox.com/scl/fi/j698pjo7jxm152zuzu4dx/ >>Pink_Triangle.jpg?
    rlkey=n4xinzzm39bms9w04syb7egkx&raw=1

    I went to one of those once in Berlin when I lived there. God almighty! >>>> I've never seen such a complete and utter freak show in my entire life. >>>> I just stood there gaping open-mouthed at the procession.

    Why were you at the procession? Why did you not stay at home or away from the procession?
    Or was it that the procession passed your home?

    It must have
    been pretty obvious to any of those weirdos on the floats that I wasn't >>>> there to celebrate them!

    Why would that have been obvious to them?

    I just find it bizarre that parents actually
    take their kids to see this sort of thing and they're all waving their >>>> rainbow flags and whatnot.

    No kids of mine would be allowed

    You could find that they remember you for that, and they may or may not ever tell you so.

    within a
    million miles of an event like that. No wonder the God-fearing folks
    reckon the world's going to hell in a handbasket. :(

    What does god have to do with such a procession?


    Could always move to places that tolerate that sort of stuff. Saudi
    Arabia. Moscow. Abilene, Texas. Lots of options.

    But Mr. Larkin seems to prefer it in San Fran and you seem to prefer
    flitting about western Europe, interesting.

    Well, I did warn John about moving to SF many years ago as I could tell
    the way it was going, but he went ahead anyway and seems to have an
    uncanny ability to only notice the nice side of the place (mainly by not >>venturing downtown, it seems).

    I've only been to SF for a 1 week visit but I can think of no reason why I wouldn't live there if I had sufficient income and a
    place to live (which seems unlikely).

    From what John has said it sounds like SF is a very tolerant place which would be a plus with me.


    You warned me? What's your real name?

    When I decided to move to SF, my friends said "But it's full of gay
    guys" to which I replied "and lots of smart beautiful women."

    Do the math on that.

    Right, we avoid the tourist traps and homeless encampments. The hills separate SF into a collection of villages, with even different
    weather.

    It's a great place to be weird. People get it.

    But 2*pi is still 2*pi even here.



    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to invalid@invalid.invalid on Mon Jul 8 12:48:09 2024
    On Mon, 8 Jul 2024 14:08:33 -0400, "Edward Rawde"
    <invalid@invalid.invalid> wrote:

    "john larkin" <jlarkin_highland_tech> wrote in message news:bge68jhpanmo6vs4j780am19vc6fh9ndfo@4ax.com...
    On Mon, 1 Jul 2024 17:49:00 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    On Mon, 1 Jul 2024 13:39:51 -0400, bitrex wrote:

    On 6/30/2024 12:45 PM, Cursitor Doom wrote:
    On Sun, 30 Jun 2024 07:38:19 -0700, john larkin wrote:

    On Sun, 30 Jun 2024 14:23:24 +0100, Cursitor Doom <cd@notformail.com> >>>>>> wrote:

    On Sun, 30 Jun 2024 06:05:41 -0700, john larkin
    <jlarkin_highland_tech> wrote:

    On Sun, 30 Jun 2024 08:44:34 +0100, Cursitor Doom
    <cd@notformail.com> wrote:

    Gentlemen,
    ...

    Today is San Francisco Pride Day (Dikes on Bikes and such) so it's a >>>>>> good day to stay close to home. Traffic and parking and everything >>>>>> will be a nightmare.

    https://sfpride.org/parade

    https://www.dropbox.com/scl/fi/j698pjo7jxm152zuzu4dx/ >>>Pink_Triangle.jpg?
    rlkey=n4xinzzm39bms9w04syb7egkx&raw=1

    I went to one of those once in Berlin when I lived there. God almighty! >>>>> I've never seen such a complete and utter freak show in my entire life. >>>>> I just stood there gaping open-mouthed at the procession.

    Why were you at the procession? Why did you not stay at home or away from the procession?
    Or was it that the procession passed your home?

    It must have
    been pretty obvious to any of those weirdos on the floats that I wasn't >>>>> there to celebrate them!

    Why would that have been obvious to them?

    I just find it bizarre that parents actually
    take their kids to see this sort of thing and they're all waving their >>>>> rainbow flags and whatnot.

    No kids of mine would be allowed

    You could find that they remember you for that, and they may or may not ever tell you so.

    within a
    million miles of an event like that. No wonder the God-fearing folks >>>>> reckon the world's going to hell in a handbasket. :(

    What does god have to do with such a procession?


    Could always move to places that tolerate that sort of stuff. Saudi
    Arabia. Moscow. Abilene, Texas. Lots of options.

    But Mr. Larkin seems to prefer it in San Fran and you seem to prefer
    flitting about western Europe, interesting.

    Well, I did warn John about moving to SF many years ago as I could tell >>>the way it was going, but he went ahead anyway and seems to have an >>>uncanny ability to only notice the nice side of the place (mainly by not >>>venturing downtown, it seems).

    I've only been to SF for a 1 week visit but I can think of no reason why I wouldn't live there if I had sufficient income and a
    place to live (which seems unlikely).

    From what John has said it sounds like SF is a very tolerant place which would be a plus with me.



    For most of human history, people didn't travel or marry much beyond
    walking distance of their birthplace. Now, all over the world, some self-selected people leave home and move to big cities, university and
    tech and business centers.

    Those places are pretty diverse so tolerant of differences.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to Edward Rawde on Mon Jul 8 19:59:41 2024
    On Mon, 8 Jul 2024 14:08:33 -0400, Edward Rawde wrote:

    "john larkin" <jlarkin_highland_tech> wrote in message news:bge68jhpanmo6vs4j780am19vc6fh9ndfo@4ax.com...
    On Mon, 1 Jul 2024 17:49:00 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    On Mon, 1 Jul 2024 13:39:51 -0400, bitrex wrote:

    On 6/30/2024 12:45 PM, Cursitor Doom wrote:
    On Sun, 30 Jun 2024 07:38:19 -0700, john larkin wrote:

    On Sun, 30 Jun 2024 14:23:24 +0100, Cursitor Doom
    <cd@notformail.com>
    wrote:

    On Sun, 30 Jun 2024 06:05:41 -0700, john larkin
    <jlarkin_highland_tech> wrote:

    On Sun, 30 Jun 2024 08:44:34 +0100, Cursitor Doom
    <cd@notformail.com> wrote:

    Gentlemen,
    ...

    Today is San Francisco Pride Day (Dikes on Bikes and such) so it's >>>>>> a good day to stay close to home. Traffic and parking and
    everything will be a nightmare.

    https://sfpride.org/parade

    https://www.dropbox.com/scl/fi/j698pjo7jxm152zuzu4dx/ >>>Pink_Triangle.jpg?
    rlkey=n4xinzzm39bms9w04syb7egkx&raw=1

    I went to one of those once in Berlin when I lived there. God
    almighty!
    I've never seen such a complete and utter freak show in my entire
    life.
    I just stood there gaping open-mouthed at the procession.

    Why were you at the procession? Why did you not stay at home or away
    from the procession?
    Or was it that the procession passed your home?

    It was an 8 minute walk to the procession and I'd never seen one before.
    I'd expected something a bit more dignified.


    It must have been pretty obvious to any of those weirdos on the
    floats that I wasn't there to celebrate them!

    Why would that have been obvious to them?

    I can't disguise my expression.

    I just find it bizarre that parents actually take their kids to see
    this sort of thing and they're all waving their rainbow flags and
    whatnot.

    No kids of mine would be allowed

    You could find that they remember you for that, and they may or may not
    ever tell you so.

    They'd be most grateful. That display was not fit for children to witness.


    within a million miles of an event like that. No wonder the
    God-fearing folks reckon the world's going to hell in a handbasket.
    :(

    What does god have to do with such a procession?

    Leviticus, I believe. 'Man shall not lay with man nor woman lay with
    woman' IIRC.

    Could always move to places that tolerate that sort of stuff. Saudi
    Arabia. Moscow. Abilene, Texas. Lots of options.

    But Mr. Larkin seems to prefer it in San Fran and you seem to prefer
    flitting about western Europe, interesting.

    Well, I did warn John about moving to SF many years ago as I could tell >>>the way it was going, but he went ahead anyway and seems to have an >>>uncanny ability to only notice the nice side of the place (mainly by
    not venturing downtown, it seems).

    I've only been to SF for a 1 week visit but I can think of no reason why
    I wouldn't live there if I had sufficient income and a place to live
    (which seems unlikely).

    From what John has said it sounds like SF is a very tolerant place which would be a plus with me.

    If you're gay, that's fine by me. What I cannot understand is why these processions are purposely - it seems to me - so outrageously offensive to normal people. They don't have to be. Why are they? Why do these people go
    out of their way to stultify their own cause? It makes no sense to me at
    all. I can't possibly celebrate behaviour like that.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to cd999666@notformail.com on Mon Jul 8 13:43:20 2024
    On Mon, 8 Jul 2024 19:59:41 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:

    On Mon, 8 Jul 2024 14:08:33 -0400, Edward Rawde wrote:

    "john larkin" <jlarkin_highland_tech> wrote in message
    news:bge68jhpanmo6vs4j780am19vc6fh9ndfo@4ax.com...
    On Mon, 1 Jul 2024 17:49:00 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    On Mon, 1 Jul 2024 13:39:51 -0400, bitrex wrote:

    On 6/30/2024 12:45 PM, Cursitor Doom wrote:
    On Sun, 30 Jun 2024 07:38:19 -0700, john larkin wrote:

    On Sun, 30 Jun 2024 14:23:24 +0100, Cursitor Doom
    <cd@notformail.com>
    wrote:

    On Sun, 30 Jun 2024 06:05:41 -0700, john larkin
    <jlarkin_highland_tech> wrote:

    On Sun, 30 Jun 2024 08:44:34 +0100, Cursitor Doom
    <cd@notformail.com> wrote:

    Gentlemen,
    ...

    Today is San Francisco Pride Day (Dikes on Bikes and such) so it's >>>>>>> a good day to stay close to home. Traffic and parking and
    everything will be a nightmare.

    https://sfpride.org/parade

    https://www.dropbox.com/scl/fi/j698pjo7jxm152zuzu4dx/ >>>>Pink_Triangle.jpg?
    rlkey=n4xinzzm39bms9w04syb7egkx&raw=1

    I went to one of those once in Berlin when I lived there. God
    almighty!
    I've never seen such a complete and utter freak show in my entire
    life.
    I just stood there gaping open-mouthed at the procession.

    Why were you at the procession? Why did you not stay at home or away
    from the procession?
    Or was it that the procession passed your home?

    It was an 8 minute walk to the procession and I'd never seen one before.
    I'd expected something a bit more dignified.


    It must have been pretty obvious to any of those weirdos on the
    floats that I wasn't there to celebrate them!

    Why would that have been obvious to them?

    I can't disguise my expression.

    I just find it bizarre that parents actually take their kids to see >>>>>> this sort of thing and they're all waving their rainbow flags and
    whatnot.

    No kids of mine would be allowed

    You could find that they remember you for that, and they may or may not
    ever tell you so.

    They'd be most grateful. That display was not fit for children to witness.


    within a million miles of an event like that. No wonder the
    God-fearing folks reckon the world's going to hell in a handbasket. >>>>>> :(

    What does god have to do with such a procession?

    Leviticus, I believe. 'Man shall not lay with man nor woman lay with
    woman' IIRC.

    Could always move to places that tolerate that sort of stuff. Saudi >>>>> Arabia. Moscow. Abilene, Texas. Lots of options.

    But Mr. Larkin seems to prefer it in San Fran and you seem to prefer >>>>> flitting about western Europe, interesting.

    Well, I did warn John about moving to SF many years ago as I could tell >>>>the way it was going, but he went ahead anyway and seems to have an >>>>uncanny ability to only notice the nice side of the place (mainly by >>>>not venturing downtown, it seems).

    I've only been to SF for a 1 week visit but I can think of no reason why
    I wouldn't live there if I had sufficient income and a place to live
    (which seems unlikely).

    From what John has said it sounds like SF is a very tolerant place which
    would be a plus with me.

    If you're gay, that's fine by me. What I cannot understand is why these >processions are purposely - it seems to me - so outrageously offensive to >normal people. They don't have to be. Why are they? Why do these people go >out of their way to stultify their own cause? It makes no sense to me at
    all. I can't possibly celebrate behaviour like that.

    If they want to celebrate their other-ness, and get mostly nekkid and
    freeze in the process, I and you can watch or not. The Folsum Fetish
    Street Fair is fun. "Normal" is very relative.

    I used to live 2 blocks from Castro street, the main gay drag, just
    before AIDS hit. It was outrageously wild, but it was fun and the food
    was good. I met my wife in a gay bar. There is an upside to being the
    only staight single male in the room.

    Now the Castro is over-run with breeders pushing baby buggies, and the
    gays are tolerant.

    Part of our religious and (former) legal condemnation of extra-marital
    and gay sex probably evolved to preventing transmitting diseases.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Edward Rawde@21:1/5 to Cursitor Doom on Mon Jul 8 17:05:09 2024
    "Cursitor Doom" <cd999666@notformail.com> wrote in message news:v6hgfc$10h93$3@dont-email.me...
    On Mon, 8 Jul 2024 14:08:33 -0400, Edward Rawde wrote:

    "john larkin" <jlarkin_highland_tech> wrote in message
    news:bge68jhpanmo6vs4j780am19vc6fh9ndfo@4ax.com...
    On Mon, 1 Jul 2024 17:49:00 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    On Mon, 1 Jul 2024 13:39:51 -0400, bitrex wrote:

    On 6/30/2024 12:45 PM, Cursitor Doom wrote:
    On Sun, 30 Jun 2024 07:38:19 -0700, john larkin wrote:

    On Sun, 30 Jun 2024 14:23:24 +0100, Cursitor Doom
    <cd@notformail.com>
    wrote:

    On Sun, 30 Jun 2024 06:05:41 -0700, john larkin
    <jlarkin_highland_tech> wrote:

    On Sun, 30 Jun 2024 08:44:34 +0100, Cursitor Doom
    <cd@notformail.com> wrote:

    Gentlemen,
    ...

    Today is San Francisco Pride Day (Dikes on Bikes and such) so it's >>>>>>> a good day to stay close to home. Traffic and parking and
    everything will be a nightmare.

    https://sfpride.org/parade

    https://www.dropbox.com/scl/fi/j698pjo7jxm152zuzu4dx/ >>>>Pink_Triangle.jpg?
    rlkey=n4xinzzm39bms9w04syb7egkx&raw=1

    I went to one of those once in Berlin when I lived there. God
    almighty!
    I've never seen such a complete and utter freak show in my entire
    life.
    I just stood there gaping open-mouthed at the procession.

    Why were you at the procession? Why did you not stay at home or away
    from the procession?
    Or was it that the procession passed your home?

    It was an 8 minute walk to the procession and I'd never seen one before.

    So you made a deliberate decision to attend.

    I'd expected something a bit more dignified.


    It must have been pretty obvious to any of those weirdos on the
    floats that I wasn't there to celebrate them!

    Why would that have been obvious to them?

    I can't disguise my expression.

    I don't think they would have cared.


    I just find it bizarre that parents actually take their kids to see >>>>>> this sort of thing and they're all waving their rainbow flags and
    whatnot.

    No kids of mine would be allowed

    You could find that they remember you for that, and they may or may not
    ever tell you so.

    They'd be most grateful.

    How do you know this? Are they allowed to think for themselves?

    That display was not fit for children to witness.


    within a million miles of an event like that. No wonder the
    God-fearing folks reckon the world's going to hell in a handbasket. >>>>>> :(

    What does god have to do with such a procession?

    Leviticus, I believe. 'Man shall not lay with man nor woman lay with
    woman' IIRC.

    Oh dear.


    Could always move to places that tolerate that sort of stuff. Saudi >>>>> Arabia. Moscow. Abilene, Texas. Lots of options.

    But Mr. Larkin seems to prefer it in San Fran and you seem to prefer >>>>> flitting about western Europe, interesting.

    Well, I did warn John about moving to SF many years ago as I could tell >>>>the way it was going, but he went ahead anyway and seems to have an >>>>uncanny ability to only notice the nice side of the place (mainly by >>>>not venturing downtown, it seems).

    I've only been to SF for a 1 week visit but I can think of no reason why
    I wouldn't live there if I had sufficient income and a place to live
    (which seems unlikely).

    From what John has said it sounds like SF is a very tolerant place which
    would be a plus with me.

    If you're gay, that's fine by me.

    LOL when did I give any indication of my sexuality? LOL
    Ok maybe you meant 'you' in the plural sense but still LOL

    What I cannot understand is why these
    processions are purposely - it seems to me - so outrageously offensive to

    normal people.

    What distinguishes a normal person from one who is not normal?

    They don't have to be. Why are they? Why do these people go
    out of their way to stultify their own cause? It makes no sense to me at
    all. I can't possibly celebrate behaviour like that.

    You don't have to deliberately attend either.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Edward Rawde@21:1/5 to All on Mon Jul 8 17:12:42 2024
    "john larkin" <jlarkin_highland_tech> wrote in message news:k2jo8jphf5vp8b14apec2sau1msuo3q3lv@4ax.com...
    On Mon, 8 Jul 2024 19:59:41 -0000 (UTC), Cursitor Doom <cd999666@notformail.com> wrote:

    On Mon, 8 Jul 2024 14:08:33 -0400, Edward Rawde wrote:

    "john larkin" <jlarkin_highland_tech> wrote in message
    news:bge68jhpanmo6vs4j780am19vc6fh9ndfo@4ax.com...
    On Mon, 1 Jul 2024 17:49:00 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    On Mon, 1 Jul 2024 13:39:51 -0400, bitrex wrote:

    On 6/30/2024 12:45 PM, Cursitor Doom wrote:
    On Sun, 30 Jun 2024 07:38:19 -0700, john larkin wrote:

    On Sun, 30 Jun 2024 14:23:24 +0100, Cursitor Doom
    <cd@notformail.com>
    wrote:

    On Sun, 30 Jun 2024 06:05:41 -0700, john larkin
    <jlarkin_highland_tech> wrote:

    On Sun, 30 Jun 2024 08:44:34 +0100, Cursitor Doom
    <cd@notformail.com> wrote:

    Gentlemen,
    ...

    Today is San Francisco Pride Day (Dikes on Bikes and such) so it's >>>>>>>> a good day to stay close to home. Traffic and parking and
    everything will be a nightmare.

    https://sfpride.org/parade

    https://www.dropbox.com/scl/fi/j698pjo7jxm152zuzu4dx/ >>>>>Pink_Triangle.jpg?
    rlkey=n4xinzzm39bms9w04syb7egkx&raw=1

    I went to one of those once in Berlin when I lived there. God
    almighty!
    I've never seen such a complete and utter freak show in my entire >>>>>>> life.
    I just stood there gaping open-mouthed at the procession.

    Part of our religious and (former) legal condemnation of extra-marital
    and gay sex probably evolved to preventing transmitting diseases.

    Ah someone making logical sense instead of expecting an irrelevant law, written 2000 years or so before English even existed, to be
    in any way relevant to here and now.
    That's refreshing.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to invalid@invalid.invalid on Mon Jul 8 16:04:31 2024
    On Mon, 8 Jul 2024 17:12:42 -0400, "Edward Rawde"
    <invalid@invalid.invalid> wrote:

    "john larkin" <jlarkin_highland_tech> wrote in message news:k2jo8jphf5vp8b14apec2sau1msuo3q3lv@4ax.com...
    On Mon, 8 Jul 2024 19:59:41 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    On Mon, 8 Jul 2024 14:08:33 -0400, Edward Rawde wrote:

    "john larkin" <jlarkin_highland_tech> wrote in message
    news:bge68jhpanmo6vs4j780am19vc6fh9ndfo@4ax.com...
    On Mon, 1 Jul 2024 17:49:00 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    On Mon, 1 Jul 2024 13:39:51 -0400, bitrex wrote:

    On 6/30/2024 12:45 PM, Cursitor Doom wrote:
    On Sun, 30 Jun 2024 07:38:19 -0700, john larkin wrote:

    On Sun, 30 Jun 2024 14:23:24 +0100, Cursitor Doom
    <cd@notformail.com>
    wrote:

    On Sun, 30 Jun 2024 06:05:41 -0700, john larkin
    <jlarkin_highland_tech> wrote:

    On Sun, 30 Jun 2024 08:44:34 +0100, Cursitor Doom
    <cd@notformail.com> wrote:

    Gentlemen,
    ...

    Today is San Francisco Pride Day (Dikes on Bikes and such) so it's >>>>>>>>> a good day to stay close to home. Traffic and parking and
    everything will be a nightmare.

    https://sfpride.org/parade

    https://www.dropbox.com/scl/fi/j698pjo7jxm152zuzu4dx/ >>>>>>Pink_Triangle.jpg?
    rlkey=n4xinzzm39bms9w04syb7egkx&raw=1

    I went to one of those once in Berlin when I lived there. God
    almighty!
    I've never seen such a complete and utter freak show in my entire >>>>>>>> life.
    I just stood there gaping open-mouthed at the procession.

    Part of our religious and (former) legal condemnation of extra-marital
    and gay sex probably evolved to preventing transmitting diseases.

    Ah someone making logical sense instead of expecting an irrelevant law, written 2000 years or so before English even existed, to be
    in any way relevant to here and now.

    The Ten Commandments still make sense. They work.

    That's refreshing.


    Social evolution probably becomes genetic evolution. They go together.

    One thing I have noted about gay guys is that they tend to be
    promiscuous, wildly so, even married ones. My theory is that women
    have some chemicals that are deeply satisfying and make us fall
    asleep. The first AIDS cases here were among people who had had
    something like 3000 sexual partners. The mind boggles.

    This is a great book:

    https://www.amazon.com/Band-Played-Politics-Epidemic-20th-Anniversary/dp/0312374631

    Randy wrote it as he was dying of AIDS.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Joe Gwinn@21:1/5 to All on Mon Jul 8 20:08:47 2024
    On Mon, 08 Jul 2024 16:04:31 -0700, john larkin
    <jlarkin_highland_tech> wrote:

    On Mon, 8 Jul 2024 17:12:42 -0400, "Edward Rawde"
    <invalid@invalid.invalid> wrote:

    "john larkin" <jlarkin_highland_tech> wrote in message news:k2jo8jphf5vp8b14apec2sau1msuo3q3lv@4ax.com...
    On Mon, 8 Jul 2024 19:59:41 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    On Mon, 8 Jul 2024 14:08:33 -0400, Edward Rawde wrote:

    "john larkin" <jlarkin_highland_tech> wrote in message
    news:bge68jhpanmo6vs4j780am19vc6fh9ndfo@4ax.com...
    On Mon, 1 Jul 2024 17:49:00 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    On Mon, 1 Jul 2024 13:39:51 -0400, bitrex wrote:

    On 6/30/2024 12:45 PM, Cursitor Doom wrote:
    On Sun, 30 Jun 2024 07:38:19 -0700, john larkin wrote:

    On Sun, 30 Jun 2024 14:23:24 +0100, Cursitor Doom
    <cd@notformail.com>
    wrote:

    On Sun, 30 Jun 2024 06:05:41 -0700, john larkin
    <jlarkin_highland_tech> wrote:

    On Sun, 30 Jun 2024 08:44:34 +0100, Cursitor Doom
    <cd@notformail.com> wrote:

    Gentlemen,
    ...

    Today is San Francisco Pride Day (Dikes on Bikes and such) so it's >>>>>>>>>> a good day to stay close to home. Traffic and parking and
    everything will be a nightmare.

    https://sfpride.org/parade

    https://www.dropbox.com/scl/fi/j698pjo7jxm152zuzu4dx/ >>>>>>>Pink_Triangle.jpg?
    rlkey=n4xinzzm39bms9w04syb7egkx&raw=1

    I went to one of those once in Berlin when I lived there. God >>>>>>>>> almighty!
    I've never seen such a complete and utter freak show in my entire >>>>>>>>> life.
    I just stood there gaping open-mouthed at the procession.

    Part of our religious and (former) legal condemnation of extra-marital
    and gay sex probably evolved to preventing transmitting diseases.

    Ah someone making logical sense instead of expecting an irrelevant law, written 2000 years or so before English even existed, to be
    in any way relevant to here and now.

    The Ten Commandments still make sense. They work.

    That's refreshing.


    Social evolution probably becomes genetic evolution. They go together.

    One thing I have noted about gay guys is that they tend to be
    promiscuous, wildly so, even married ones. My theory is that women
    have some chemicals that are deeply satisfying and make us fall
    asleep. The first AIDS cases here were among people who had had
    something like 3000 sexual partners. The mind boggles.

    This is a great book:

    <https://www.amazon.com/Band-Played-Politics-Epidemic-20th-Anniversary/dp/0312374631>

    Randy wrote it as he was dying of AIDS.

    Yeah. A college roommate became a doctor, and while still in school
    attended a lecture presenting early reports, which mentioned men who
    had about 1000 partners in a year.

    Which stunned me - that would be an average of three a day for each
    and every day of the year. How does one do this physically? Well,
    they managed.

    I think that they noticed that hemophiliacs were also being hit, but
    not the women. This being before AIDS transitioned to the general
    population.

    Joe Gwinn

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Edward Rawde@21:1/5 to All on Mon Jul 8 20:15:19 2024
    "john larkin" <jlarkin_highland_tech> wrote in message news:5fro8jlc0gcrjsbipkronnugo18lp54hm7@4ax.com...
    On Mon, 8 Jul 2024 17:12:42 -0400, "Edward Rawde"
    <invalid@invalid.invalid> wrote:

    "john larkin" <jlarkin_highland_tech> wrote in message news:k2jo8jphf5vp8b14apec2sau1msuo3q3lv@4ax.com...
    On Mon, 8 Jul 2024 19:59:41 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    On Mon, 8 Jul 2024 14:08:33 -0400, Edward Rawde wrote:

    "john larkin" <jlarkin_highland_tech> wrote in message
    news:bge68jhpanmo6vs4j780am19vc6fh9ndfo@4ax.com...
    On Mon, 1 Jul 2024 17:49:00 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    On Mon, 1 Jul 2024 13:39:51 -0400, bitrex wrote:

    On 6/30/2024 12:45 PM, Cursitor Doom wrote:
    On Sun, 30 Jun 2024 07:38:19 -0700, john larkin wrote:

    On Sun, 30 Jun 2024 14:23:24 +0100, Cursitor Doom
    <cd@notformail.com>
    wrote:

    On Sun, 30 Jun 2024 06:05:41 -0700, john larkin
    <jlarkin_highland_tech> wrote:

    On Sun, 30 Jun 2024 08:44:34 +0100, Cursitor Doom
    <cd@notformail.com> wrote:

    Gentlemen,
    ...

    Today is San Francisco Pride Day (Dikes on Bikes and such) so it's >>>>>>>>>> a good day to stay close to home. Traffic and parking and
    everything will be a nightmare.

    https://sfpride.org/parade

    https://www.dropbox.com/scl/fi/j698pjo7jxm152zuzu4dx/ >>>>>>>Pink_Triangle.jpg?
    rlkey=n4xinzzm39bms9w04syb7egkx&raw=1

    I went to one of those once in Berlin when I lived there. God >>>>>>>>> almighty!
    I've never seen such a complete and utter freak show in my entire >>>>>>>>> life.
    I just stood there gaping open-mouthed at the procession.

    Part of our religious and (former) legal condemnation of extra-marital
    and gay sex probably evolved to preventing transmitting diseases.

    Ah someone making logical sense instead of expecting an irrelevant law, written 2000 years or so before English even existed, to
    be
    in any way relevant to here and now.

    The Ten Commandments still make sense. They work.

    I don't recall all of them but some such as thou shalt not kill/steal are clearly fine.

    I think the seven commandments are more interesting but that's a bit off topic. https://www.google.com/search?q="jones+of+the+manor+farm"anger+pdf
    For anyone who hasn't read it.


    That's refreshing.


    Social evolution probably becomes genetic evolution. They go together.

    One thing I have noted about gay guys is that they tend to be
    promiscuous, wildly so, even married ones.

    I hadn't noticed myself but I have limited knowledge of such matters and haven't done any research into it.

    My theory is that women
    have some chemicals that are deeply satisfying and make us fall
    asleep. The first AIDS cases here were among people who had had
    something like 3000 sexual partners. The mind boggles.

    This is a great book:

    https://www.amazon.com/Band-Played-Politics-Epidemic-20th-Anniversary/dp/0312374631

    Randy wrote it as he was dying of AIDS.


    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Bill Sloman@21:1/5 to Cursitor Doom on Tue Jul 9 13:49:24 2024
    On 9/07/2024 5:59 am, Cursitor Doom wrote:
    On Mon, 8 Jul 2024 14:08:33 -0400, Edward Rawde wrote:

    "john larkin" <jlarkin_highland_tech> wrote in message
    news:bge68jhpanmo6vs4j780am19vc6fh9ndfo@4ax.com...
    On Mon, 1 Jul 2024 17:49:00 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    On Mon, 1 Jul 2024 13:39:51 -0400, bitrex wrote:

    On 6/30/2024 12:45 PM, Cursitor Doom wrote:
    On Sun, 30 Jun 2024 07:38:19 -0700, john larkin wrote:

    On Sun, 30 Jun 2024 14:23:24 +0100, Cursitor Doom
    <cd@notformail.com>
    wrote:

    On Sun, 30 Jun 2024 06:05:41 -0700, john larkin
    <jlarkin_highland_tech> wrote:

    On Sun, 30 Jun 2024 08:44:34 +0100, Cursitor Doom
    <cd@notformail.com> wrote:

    <snip>

    If you're gay, that's fine by me. What I cannot understand is why these processions are purposely - it seems to me - so outrageously offensive to normal people. They don't have to be. Why are they?

    What makes you think that they outrageously offensive to normal people?
    Are you making the obvious mistake of thinking that you are normal?

    Why do these people go out of their way to stultify their own cause?

    "Stultify"?

    It makes no sense to me at all. I can't possibly celebrate behavior like
    that.

    You aren't expected to. You might be expected to realise that there are different strokes for different folks, and that this is the behavior
    that they want to celebrate. You own bizarre sources of gratification
    may get in the way of that.

    --
    Bill Sloman, Sydney


    --
    This email has been checked for viruses by Norton antivirus software. www.norton.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jeroen Belleman@21:1/5 to john larkin on Tue Jul 9 10:21:39 2024
    On 7/9/24 01:04, john larkin wrote:
    [...]

    The Ten Commandments still make sense. They work.


    The first three are just job protection. The last six
    can be summarized as "Don't do to others what you don't
    want them to do to you." There. Just two will suffice.

    Jeroen Belleman

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From john larkin @21:1/5 to jeroen@nospam.please on Tue Jul 9 06:47:04 2024
    On Tue, 9 Jul 2024 10:21:39 +0200, Jeroen Belleman
    <jeroen@nospam.please> wrote:

    On 7/9/24 01:04, john larkin wrote:
    [...]

    The Ten Commandments still make sense. They work.


    The first three are just job protection. The last six
    can be summarized as "Don't do to others what you don't
    want them to do to you." There. Just two will suffice.

    Jeroen Belleman

    I think that the commandments were the first steps of the Enlightment,
    which has a way to go still.

    Islam and communism are steps in the wrong direction.

    "Don't do to others" has its own problems. For starters, individuals
    will have different opinions about what's OK. Rape and bank robbery
    should be illegal for everyone.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Bill Sloman@21:1/5 to john larkin on Wed Jul 10 01:25:07 2024
    On 9/07/2024 11:47 pm, john larkin wrote:
    On Tue, 9 Jul 2024 10:21:39 +0200, Jeroen Belleman
    <jeroen@nospam.please> wrote:

    On 7/9/24 01:04, john larkin wrote:
    [...]

    The Ten Commandments still make sense. They work.


    The first three are just job protection. The last six
    can be summarized as "Don't do to others what you don't
    want them to do to you." There. Just two will suffice.

    Jeroen Belleman

    I think that the commandments were the first steps of the Enlightment,
    which has a way to go still.

    Islam and communism are steps in the wrong direction.

    Two very different philosophies. Islam is one more religion.

    Communism - or rather socialism - was based on "to each according to
    their needs, from each according to their abilities" which is pretty
    sensible. Working out the details is complicated. Democratic socialism
    works pretty well. Autocratic communism doesn't.

    "Don't do to others" has its own problems. For starters, individuals
    will have different opinions about what's OK. Rape and bank robbery
    should be illegal for everyone.

    Nobody wants to be raped or robbed. Other peoples opinions about what constitutes rape can be strange."Statutory rape" gets complicated.
    "Robbery" is less fraught.

    Introducing a lawyer into the discussions is probably a bad idea. They
    make money out creating ever finer distinctions, and writing them into inflexible statutes, which they make even more money out of interpreting.

    --
    Bill Sloman, Sydney



    --
    This email has been checked for viruses by Norton antivirus software. www.norton.com

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jasen Betts@21:1/5 to Cursitor Doom on Wed Jul 10 07:47:29 2024
    On 2024-06-30, Cursitor Doom <cd@notformail.com> wrote:
    On Sun, 30 Jun 2024 11:57:21 +0100, piglet <erichpwagner@hotmail.com>
    wrote:


    Thanks, Erich. I did wonder if radians had something to do with it.
    However, knowing that 2 pi radians = 360 degrees or a full wavelength
    doesn't help me understand why this figure multiplied by the frequency multiplied by the inductance gives us the reactance of a coil. Small
    omega therefore equals one second's worth of signal and I don't get
    how multipying that by the inductance amounts to the reactance!

    Something abourt e to the power of sqrt(-1) times theta

    --
    Jasen.
    🇺🇦 Слава Україні

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to Jasen Betts on Wed Jul 10 17:23:09 2024
    On Wed, 10 Jul 2024 07:47:29 -0000 (UTC), Jasen Betts wrote:

    On 2024-06-30, Cursitor Doom <cd@notformail.com> wrote:
    On Sun, 30 Jun 2024 11:57:21 +0100, piglet <erichpwagner@hotmail.com>
    wrote:


    Thanks, Erich. I did wonder if radians had something to do with it.
    However, knowing that 2 pi radians = 360 degrees or a full wavelength
    doesn't help me understand why this figure multiplied by the frequency
    multiplied by the inductance gives us the reactance of a coil. Small
    omega therefore equals one second's worth of signal and I don't get how
    multipying that by the inductance amounts to the reactance!

    Something abourt e to the power of sqrt(-1) times theta

    Well this is something else that's new to me. I only just encountered it
    last month when reading Tom Lee's book 'Planar Microwave Engineering' in
    which he uses some very unfamiliar (to me) mathematics. I was going to
    post a question about it here in fact. Mebe I'll get around to it if time permits...

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Cursitor Doom@21:1/5 to Edward Rawde on Wed Jul 10 17:44:12 2024
    On Mon, 8 Jul 2024 17:05:09 -0400, Edward Rawde wrote:

    "Cursitor Doom" <cd999666@notformail.com> wrote in message news:v6hgfc$10h93$3@dont-email.me...
    On Mon, 8 Jul 2024 14:08:33 -0400, Edward Rawde wrote:

    "john larkin" <jlarkin_highland_tech> wrote in message
    news:bge68jhpanmo6vs4j780am19vc6fh9ndfo@4ax.com...
    On Mon, 1 Jul 2024 17:49:00 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    On Mon, 1 Jul 2024 13:39:51 -0400, bitrex wrote:

    On 6/30/2024 12:45 PM, Cursitor Doom wrote:
    On Sun, 30 Jun 2024 07:38:19 -0700, john larkin wrote:

    On Sun, 30 Jun 2024 14:23:24 +0100, Cursitor Doom
    <cd@notformail.com>
    wrote:

    On Sun, 30 Jun 2024 06:05:41 -0700, john larkin
    <jlarkin_highland_tech> wrote:

    On Sun, 30 Jun 2024 08:44:34 +0100, Cursitor Doom
    <cd@notformail.com> wrote:

    Gentlemen,
    ...

    Today is San Francisco Pride Day (Dikes on Bikes and such) so
    it's a good day to stay close to home. Traffic and parking and >>>>>>>> everything will be a nightmare.

    https://sfpride.org/parade

    https://www.dropbox.com/scl/fi/j698pjo7jxm152zuzu4dx/ >>>>>Pink_Triangle.jpg?
    rlkey=n4xinzzm39bms9w04syb7egkx&raw=1

    I went to one of those once in Berlin when I lived there. God
    almighty!
    I've never seen such a complete and utter freak show in my entire >>>>>>> life.
    I just stood there gaping open-mouthed at the procession.

    Why were you at the procession? Why did you not stay at home or away
    from the procession?
    Or was it that the procession passed your home?

    It was an 8 minute walk to the procession and I'd never seen one
    before.

    So you made a deliberate decision to attend.

    I'd expected something a bit more dignified.


    It must have been pretty obvious to any of those weirdos on the
    floats that I wasn't there to celebrate them!

    Why would that have been obvious to them?

    I can't disguise my expression.

    I don't think they would have cared.


    I just find it bizarre that parents actually take their kids to
    see this sort of thing and they're all waving their rainbow flags >>>>>>> and whatnot.

    No kids of mine would be allowed

    You could find that they remember you for that, and they may or may
    not ever tell you so.

    They'd be most grateful.

    How do you know this? Are they allowed to think for themselves?

    That display was not fit for children to witness.


    within a million miles of an event like that. No wonder the
    God-fearing folks reckon the world's going to hell in a
    handbasket.
    :(

    What does god have to do with such a procession?

    Leviticus, I believe. 'Man shall not lay with man nor woman lay with
    woman' IIRC.

    Oh dear.


    Could always move to places that tolerate that sort of stuff.
    Saudi Arabia. Moscow. Abilene, Texas. Lots of options.

    But Mr. Larkin seems to prefer it in San Fran and you seem to
    prefer flitting about western Europe, interesting.

    Well, I did warn John about moving to SF many years ago as I could >>>>>tell the way it was going, but he went ahead anyway and seems to have >>>>>an uncanny ability to only notice the nice side of the place (mainly >>>>>by not venturing downtown, it seems).

    I've only been to SF for a 1 week visit but I can think of no reason
    why I wouldn't live there if I had sufficient income and a place to
    live (which seems unlikely).

    From what John has said it sounds like SF is a very tolerant place
    which would be a plus with me.

    If you're gay, that's fine by me.

    LOL when did I give any indication of my sexuality? LOL Ok maybe you
    meant 'you' in the plural sense but still LOL

    What I cannot understand is why these processions are purposely - it
    seems to me - so outrageously offensive to

    normal people.
    b
    What distinguishes a normal person from one who is not normal?

    They don't have to be. Why are they? Why do these people go out of
    their way to stultify their own cause? It makes no sense to me at all.
    I can't possibly celebrate behaviour like that.

    You don't have to deliberately attend either.

    I only went out of curiosity. Never seen one before.
    And I'll never watch another one. A re-enactment of a Bacchanalian orgie
    is not the kind of entertainment I like to see and is 100% NOT suitable
    for children. Anyone who takes a child to see an event like that needs to
    have the child taken away and fostered to a loving heterosexual couple who
    will bring it up properly.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Edward Rawde@21:1/5 to Cursitor Doom on Wed Jul 10 14:21:31 2024
    "Cursitor Doom" <cd999666@notformail.com> wrote in message news:v6mh9c$20818$5@dont-email.me...
    On Mon, 8 Jul 2024 17:05:09 -0400, Edward Rawde wrote:

    "Cursitor Doom" <cd999666@notformail.com> wrote in message
    news:v6hgfc$10h93$3@dont-email.me...
    On Mon, 8 Jul 2024 14:08:33 -0400, Edward Rawde wrote:

    "john larkin" <jlarkin_highland_tech> wrote in message
    news:bge68jhpanmo6vs4j780am19vc6fh9ndfo@4ax.com...
    On Mon, 1 Jul 2024 17:49:00 -0000 (UTC), Cursitor Doom
    <cd999666@notformail.com> wrote:

    On Mon, 1 Jul 2024 13:39:51 -0400, bitrex wrote:

    On 6/30/2024 12:45 PM, Cursitor Doom wrote:
    On Sun, 30 Jun 2024 07:38:19 -0700, john larkin wrote:

    On Sun, 30 Jun 2024 14:23:24 +0100, Cursitor Doom
    <cd@notformail.com>
    wrote:

    On Sun, 30 Jun 2024 06:05:41 -0700, john larkin
    <jlarkin_highland_tech> wrote:

    On Sun, 30 Jun 2024 08:44:34 +0100, Cursitor Doom
    <cd@notformail.com> wrote:

    ....
    I only went out of curiosity. Never seen one before.
    And I'll never watch another one. A re-enactment of a Bacchanalian orgie
    is not the kind of entertainment I like to see

    https://www.google.com/search?&q=Bacchanalian%20orgy&udm=2

    Looks pretty tame to me compared with some of the image searches I could have done.

    and is 100% NOT suitable
    for children. Anyone who takes a child to see an event like that needs to have the child taken away and fostered to a loving heterosexual couple who will bring it up properly.

    Children will pick up plenty of things you may not want them to know or may not think they know.
    And in general they will only take in what they are ready to understand.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jasen Betts@21:1/5 to Cursitor Doom on Thu Jul 11 08:18:12 2024
    yOn 2024-07-10, Cursitor Doom <cd999666@notformail.com> wrote:
    On Wed, 10 Jul 2024 07:47:29 -0000 (UTC), Jasen Betts wrote:

    On 2024-06-30, Cursitor Doom <cd@notformail.com> wrote:
    On Sun, 30 Jun 2024 11:57:21 +0100, piglet <erichpwagner@hotmail.com>
    wrote:


    Thanks, Erich. I did wonder if radians had something to do with it.
    However, knowing that 2 pi radians = 360 degrees or a full wavelength
    doesn't help me understand why this figure multiplied by the frequency
    multiplied by the inductance gives us the reactance of a coil. Small
    omega therefore equals one second's worth of signal and I don't get how
    multipying that by the inductance amounts to the reactance!

    Something abourt e to the power of sqrt(-1) times theta

    Well this is something else that's new to me. I only just encountered it
    last month when reading Tom Lee's book 'Planar Microwave Engineering' in which he uses some very unfamiliar (to me) mathematics. I was going to
    post a question about it here in fact. Mebe I'll get around to it if time permits...

    Phill H has covered what I was thinking of in extensive detail,
    so I will not waste your time with my inferior take on the same angle.

    --
    Jasen.
    🇺🇦 Слава Україні

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)