I have an amplified Sub woofer, but it seems to be very prone to picking >stuff up. For example, it can pick up switching transients and up until
quite recently, even Radio China International. The Chinese seem to have >lowered their power recently, but back when I first got it, you could hear >Vatican Radio as well, but these days they don't use short waves. Its >interesting to note it does not pick up Premier radio, even though there is >an am outlet less than a mile away.
We tried mains filters internal capacitors everywhere with no effect. It
even did it connected just to the mains and no inputs. I can only deduce
that the power amp design is just wide open and allows most stuff into the >amp where it just gets rectified and shoved out through the speaker.
I once had a Tandberg tuner amp that was like this, and no amount of
suppression would work there either.
Brian
In most all instances of this type of radio pickup its being demodulated
in around the first semiconductor base emitter junction it finds!.
Bypassing the junction with say a 1000 pf ceramic cap will cure that, it works much better than all the ferrite beads and the like. A few k ohms
in line with that base junction as long as its not in the biasing chain
will help as well.
In article <u987or$22saf$1@dont-email.me>, Brian Gaff
<brian1gaff@gmail.com> scribeth thus
I have an amplified Sub woofer, but it seems to be very prone to picking >>stuff up. For example, it can pick up switching transients and up until >>quite recently, even Radio China International. The Chinese seem to have >>lowered their power recently, but back when I first got it, you could hear >>Vatican Radio as well, but these days they don't use short waves. Its >>interesting to note it does not pick up Premier radio, even though there
is
an am outlet less than a mile away.
We tried mains filters internal capacitors everywhere with no effect. It >>even did it connected just to the mains and no inputs. I can only deduce >>that the power amp design is just wide open and allows most stuff into the >>amp where it just gets rectified and shoved out through the speaker.
I once had a Tandberg tuner amp that was like this, and no amount of >>suppression would work there either.
Brian
In most all instances of this type of radio pickup its being demodulated
in around the first semiconductor base emitter junction it finds!.
Bypassing the junction with say a 1000 pf ceramic cap will cure that, it works much better than all the ferrite beads and the like. A few k ohms
in line with that base junction as long as its not in the biasing chain
will help as well.
Seen this in a lot of TV audio cars even since waay back on 27 MHz AM CB systems and mobile phone breakthrough the thermostat arcing the lot!!
--
Tony Sayer
Man is least himself when he talks in his own person.
Give him a keyboard, and he will reveal himself.
On 7/21/23 12:46, tony sayer wrote:
In most all instances of this type of radio pickup its being demodulated
in around the first semiconductor base emitter junction it finds!.
Bypassing the junction with say a 1000 pf ceramic cap will cure that, it
works much better than all the ferrite beads and the like. A few k ohms
in line with that base junction as long as its not in the biasing chain
will help as well.
I seem to remember an industry meddling EU rule that made compulsory the installation of those capacitors.
Some folks paid extra for them to be removed ....
--
Adrian C
Seen this in a lot of TV audio cars even since waay back on 27 MHz AM CB systems and mobile phone breakthrough the thermostat arcing the lot!!
The ultimate *visible* RFI was on the news reports from the warships in
the Falklands War. To begin with, the reports were always preceded by
an apology for the poor picture quality - because the ship's rotating
radar pulse stomped a great big noise bar over the picture every couple
of seconds. Of course film would have been immune but there would have
been the "little" problem of taking a film-processing system and
telecine ;-)
ENG cameras have to be immune to all *normal* RFI, but immunity from a >megawatt of SHF from a radar wouldn't have been tested for ;-)
Don't know whether it affected the electronics as such (amplifiers etc)
or whether it buggered up the electron beams inside the plumbicon tubes
- because the early 80s were almost certainly before solid-state
sensors.
I'm sure we tried that as well. It worked on a tape recorder, but not on other things. Indeed, those with long memories will recall the Sinclair IC12 amplifier chips. I built a couple of these for stereo in my little bedroom when I was younger. They persistently picked up radar pulses from the industrial estate down the road. Scanning for these put them in between band 4 and 5 where videos used to live as well. Nothing else was picked up. I had to replace one due to a short in the speaker blowing it up and it was then made by Texas and still had the same problem, but later on making the power section use ILP modules got rid of it. One has to imagine that the IC was i
n fact a glorified op amp of course, and had many more transistors in a very small area than you needed for the gain you used, so many more chances to pick up crud.
On 7/21/23 12:46, tony sayer wrote:
In most all instances of this type of radio pickup its being demodulated
in around the first semiconductor base emitter junction it finds!.
Bypassing the junction with say a 1000 pf ceramic cap will cure that, it
works much better than all the ferrite beads and the like. A few k ohms
in line with that base junction as long as its not in the biasing chain
will help as well.
I seem to remember an industry meddling EU rule that made compulsory the >installation of those capacitors.
Some folks paid extra for them to be removed ....
On 22/07/2023 11:45, Brian Gaff wrote:
I'm sure we tried that as well. It worked on a tape recorder, but not
on other things. Indeed, those with long memories will recall the
Sinclair IC12 amplifier chips. I built a couple of these for stereo in
my little bedroom when I was younger. They persistently picked up radar pulses from the industrial estate down the road. Scanning for these put them in between band 4 and 5 where videos used to live as well. Nothing else was picked up. I had to replace one due to a short in the speaker blowing it up and it was then made by Texas and still had the same
problem, but later on making the power section use ILP modules got rid
of it. One has to imagine that the IC was i n fact a glorified op amp
of course, and had many more transistors in a very small area than you needed for the gain you used, so many more chances to pick up crud.
The ultimate *visible* RFI was on the news reports from the warships in
the Falklands War. To begin with, the reports were always preceded by an apology for the poor picture quality - because the ship's rotating radar pulse stomped a great big noise bar over the picture every couple of
seconds. Of course film would have been immune but there would have been
the "little" problem of taking a film-processing system and telecine ;-)
ENG cameras have to be immune to all *normal* RFI, but immunity from a megawatt of SHF from a radar wouldn't have been tested for ;-)
Don't know whether it affected the electronics as such (amplifiers etc)
or whether it buggered up the electron beams inside the plumbicon tubes
- because the early 80s were almost certainly before solid-state sensors.
I'm sure we tried that as well. It worked on a tape recorder, but not on >other things. Indeed, those with long memories will recall the Sinclair IC12 >amplifier chips. I built a couple of these for stereo in my little bedroom >when I was younger. They persistently picked up radar pulses from the >industrial estate down the road. Scanning for these put them in between band >4 and 5 where videos used to live as well. Nothing else was picked up. I had >to replace one due to a short in the speaker blowing it up and it was then >made by Texas and still had the same problem, but later on making the power >section use ILP modules got rid of it. One has to imagine that the IC was i
n fact a glorified op amp of course, and had many more transistors in a very >small area than you needed for the gain you used, so many more chances to >pick up crud.
Brian
On 21/07/2023 12:46, tony sayer wrote:
Seen this in a lot of TV audio cars even since waay back on 27 MHz AM CB
systems and mobile phone breakthrough the thermostat arcing the lot!!
My car, or maybe it was the one before it, was prone to picking up 2G
mobile phone "galloping horses" through the radio speakers even with the >radio turned off. But maybe the on/off switch just turned off the
display and front panel, and muted the RF detector input, and the
amplifier was permanently powered.
These days, "galloping horses" are like white dogshit: remembered but
not encountered for yonks.
On 22/07/2023 11:45, Brian Gaff wrote:
I'm sure we tried that as well. It worked on a tape recorder, but not on
other things. Indeed, those with long memories will recall the Sinclair IC12 >> amplifier chips. I built a couple of these for stereo in my little bedroom >> when I was younger. They persistently picked up radar pulses from the
industrial estate down the road. Scanning for these put them in between band >> 4 and 5 where videos used to live as well. Nothing else was picked up. I had >> to replace one due to a short in the speaker blowing it up and it was then >> made by Texas and still had the same problem, but later on making the power >> section use ILP modules got rid of it. One has to imagine that the IC was i >> n fact a glorified op amp of course, and had many more transistors in a very >> small area than you needed for the gain you used, so many more chances to
pick up crud.
The ultimate *visible* RFI was on the news reports from the warships in
the Falklands War. To begin with, the reports were always preceded by an >apology for the poor picture quality - because the ship's rotating radar >pulse stomped a great big noise bar over the picture every couple of
seconds. Of course film would have been immune but there would have been
the "little" problem of taking a film-processing system and telecine ;-)
ENG cameras have to be immune to all *normal* RFI, but immunity from a >megawatt of SHF from a radar wouldn't have been tested for ;-)
Don't know whether it affected the electronics as such (amplifiers etc)
or whether it buggered up the electron beams inside the plumbicon tubes
- because the early 80s were almost certainly before solid-state sensors.
In article <qa-dnX8z1ri7fib5nZ2dnZfqnPWdnZ2d@brightview.co.uk>, NY <me@privacy.net> scribeth thus
On 21/07/2023 12:46, tony sayer wrote:
Seen this in a lot of TV audio cars even since waay back on 27 MHz AM CB >>> systems and mobile phone breakthrough the thermostat arcing the lot!!
My car, or maybe it was the one before it, was prone to picking up 2G
mobile phone "galloping horses" through the radio speakers even with the
radio turned off. But maybe the on/off switch just turned off the
display and front panel, and muted the RF detector input, and the
amplifier was permanently powered.
These days, "galloping horses" are like white dogshit: remembered but
not encountered for yonks.
We used to get a lot of problems with PMR breakthrough in cars electric windows would go up and down etc!
Worst one was the old police Volvo's 144 model IIRC it seemed the
electronic fuel injection would cause the engine to stall when the radio
was transmitting!...
On Sat 22/07/2023 16:15, tony sayer wrote:
In article <qa-dnX8z1ri7fib5nZ2dnZfqnPWdnZ2d@brightview.co.uk>, NYNot quite Tony - I remember that one distinctly.
<me@privacy.net> scribeth thus
On 21/07/2023 12:46, tony sayer wrote:
Seen this in a lot of TV audio cars even since waay back on 27 MHz AM CB >>>> systems and mobile phone breakthrough the thermostat arcing the lot!!
My car, or maybe it was the one before it, was prone to picking up 2G
mobile phone "galloping horses" through the radio speakers even with the >>> radio turned off. But maybe the on/off switch just turned off the
display and front panel, and muted the RF detector input, and the
amplifier was permanently powered.
These days, "galloping horses" are like white dogshit: remembered but
not encountered for yonks.
We used to get a lot of problems with PMR breakthrough in cars electric
windows would go up and down etc!
Worst one was the old police Volvo's 144 model IIRC it seemed the
electronic fuel injection would cause the engine to stall when the radio
was transmitting!...
The Volvo 144's had the first ever electronic (i.e. transistor switched) >ignition. If the radio (Pye Vanguard of course on 79MHz-ish) transmitted
the car speed dropped by almost exactly 30mph consistently.
The lads at Pye Cambridge Service at Arbury Road cured it with some ease
- they wrapped the 'electronic ignition' plastic box in (grounded)
cooking foil. 100% instant cure!
The lads at Pye Cambridge Service at Arbury Road cured it with some ease
- they wrapped the 'electronic ignition' plastic box in (grounded)
cooking foil. 100% instant cure!
In article <u9gsok$3s0ub$1@dont-email.me>, Woody
<harrogate3@ntlworld.com> scribeth thus
On Sat 22/07/2023 16:15, tony sayer wrote:
In article <qa-dnX8z1ri7fib5nZ2dnZfqnPWdnZ2d@brightview.co.uk>, NYNot quite Tony - I remember that one distinctly. The Volvo 144's had the >first ever electronic (i.e. transistor switched) ignition. If the radio >(Pye Vanguard of course on 79MHz-ish) transmitted the car speed dropped
<me@privacy.net> scribeth thus
On 21/07/2023 12:46, tony sayer wrote:
Seen this in a lot of TV audio cars even since waay back on 27 MHz
AM CB systems and mobile phone breakthrough the thermostat arcing
the lot!!
My car, or maybe it was the one before it, was prone to picking up 2G
mobile phone "galloping horses" through the radio speakers even with
the radio turned off. But maybe the on/off switch just turned off the
display and front panel, and muted the RF detector input, and the
amplifier was permanently powered.
These days, "galloping horses" are like white dogshit: remembered but
not encountered for yonks.
We used to get a lot of problems with PMR breakthrough in cars
electric windows would go up and down etc!
Worst one was the old police Volvo's 144 model IIRC it seemed the
electronic fuel injection would cause the engine to stall when the
radio was transmitting!...
by almost exactly 30mph consistently. The lads at Pye Cambridge Service
at Arbury Road cured it with some ease - they wrapped the 'electronic >ignition' plastic box in (grounded) cooking foil. 100% instant cure!
I indeed thank my noble friend from 'opp North:).
Who will I'm sure admit this was a long time ago now and the memory?,
well thats what we read in the Cambridge even news IIRC!...
In article <u9gc08$3pd6l$1@dont-email.me>, Brian Gaff
<brian1gaff@gmail.com> scribeth thus
I'm sure we tried that as well. It worked on a tape recorder, but not on >other things. Indeed, those with long memories will recall the Sinclair IC12 >amplifier chips. I built a couple of these for stereo in my little bedroom >when I was younger. They persistently picked up radar pulses from the >industrial estate down the road. Scanning for these put them in between band >4 and 5 where videos used to live as well. Nothing else was picked up. I had >to replace one due to a short in the speaker blowing it up and it was then >made by Texas and still had the same problem, but later on making the power >section use ILP modules got rid of it. One has to imagine that the IC was i >n fact a glorified op amp of course, and had many more transistors in a very >small area than you needed for the gain you used, so many more chances to >pick up crud.
Brian
You were very lucky if the bloody things worked anyway, piles of the proverbial poo!..
Forever taking the bloody things X-20 was it down to their place in
Fitzroy street!.
Bloke there let on he'd be buying the rejects from Newmarket transistors
on the cheap!
These days, "galloping horses" are like white dogshit: remembered but
not encountered for yonks.
tony sayer <tony@bancom.co.uk> wrote:[]
In article <u9gc08$3pd6l$1@dont-email.me>, Brian Gaff
<brian1gaff@gmail.com> scribeth thus
I'm sure we tried that as well. It worked on a tape recorder, but not on
other things. Indeed, those with long memories will recall the Sinclair IC12
Bloke there let on he'd be buying the rejects from Newmarket transistors
on the cheap!
I also heard that. A friend of mine briefly worked for Sinclair and
told me that was what he did.
In article <u9gsok$3s0ub$1@dont-email.me>, Woody
<harrogate3@ntlworld.com> scribeth thus
On Sat 22/07/2023 16:15, tony sayer wrote:I indeed thank my noble friend from 'opp North:).
In article <qa-dnX8z1ri7fib5nZ2dnZfqnPWdnZ2d@brightview.co.uk>, NYNot quite Tony - I remember that one distinctly.
<me@privacy.net> scribeth thus
On 21/07/2023 12:46, tony sayer wrote:
Seen this in a lot of TV audio cars even since waay back on 27 MHz AM CB >>>>> systems and mobile phone breakthrough the thermostat arcing the lot!! >>>>My car, or maybe it was the one before it, was prone to picking up 2G
mobile phone "galloping horses" through the radio speakers even with the >>>> radio turned off. But maybe the on/off switch just turned off the
display and front panel, and muted the RF detector input, and the
amplifier was permanently powered.
These days, "galloping horses" are like white dogshit: remembered but
not encountered for yonks.
We used to get a lot of problems with PMR breakthrough in cars electric
windows would go up and down etc!
Worst one was the old police Volvo's 144 model IIRC it seemed the
electronic fuel injection would cause the engine to stall when the radio >>> was transmitting!...
The Volvo 144's had the first ever electronic (i.e. transistor switched)
ignition. If the radio (Pye Vanguard of course on 79MHz-ish) transmitted
the car speed dropped by almost exactly 30mph consistently.
The lads at Pye Cambridge Service at Arbury Road cured it with some ease
- they wrapped the 'electronic ignition' plastic box in (grounded)
cooking foil. 100% instant cure!
Who will I'm sure admit this was a long time ago now and the memory?,
well thats what we read in the Cambridge even news IIRC!...
The ultimate *visible* RFI was on the news reports from the warships in
the Falklands War. To begin with, the reports were always preceded by an apology for the poor picture quality - because the ship's rotating radar pulse stomped a great big noise bar over the picture every couple of
seconds. Of course film would have been immune but there would have been
the "little" problem of taking a film-processing system and telecine ;-)
NY <me@privacy.net> wrote:
[...]
These days, "galloping horses" are like white dogshit: remembered but
not encountered for yonks.
I don't remember white dog shit - but that's probably because I have a >terrible memory for faeces.
On Sat, 22 Jul 2023 15:18:44 +0100, NY wrote:
The ultimate *visible* RFI was on the news reports from the warships in
the Falklands War. To begin with, the reports were always preceded by
an apology for the poor picture quality - because the ship's rotating
radar pulse stomped a great big noise bar over the picture every couple
of seconds. Of course film would have been immune but there would have
been the "little" problem of taking a film-processing system and
telecine ;-)
Sometime around the late '60s or early 70s I was recording on 2" quad VTR
for ABC of America the arrival of Richard Nixon at Heathrow from a feed
of a BBC OB unit, but as Air Force One came in to land it's anti-missile defence electronics completely wiped out the Beeb's microwave link and
we lost the picture.
I have an amplified Sub woofer, but it seems to be very prone to picking stuff up. For example, it can pick up switching transients and up until
quite recently, even Radio China International. The Chinese seem to have lowered their power recently, but back when I first got it, you could
hear Vatican Radio as well, but these days they don't use short waves.
Its interesting to note it does not pick up Premier radio, even though
there is an am outlet less than a mile away.
We tried mains filters internal capacitors everywhere with no effect.
It
even did it connected just to the mains and no inputs. I can only deduce
that the power amp design is just wide open and allows most stuff into
the amp where it just gets rectified and shoved out through the speaker.
I once had a Tandberg tuner amp that was like this, and no amount of suppression would work there either.
Brian
The ultimate *visible* RFI was on the news reports from the warships in
the Falklands War. To begin with, the reports were always preceded by an >apology for the poor picture quality - because the ship's rotating radar >pulse stomped a great big noise bar over the picture every couple of
seconds. Of course film would have been immune but there would have been
the "little" problem of taking a film-processing system and telecine ;-)
ENG cameras have to be immune to all *normal* RFI, but immunity from a >megawatt of SHF from a radar wouldn't have been tested for ;-)
Don't know whether it affected the electronics as such (amplifiers etc)
or whether it buggered up the electron beams inside the plumbicon tubes
- because the early 80s were almost certainly before solid-state sensors.
In message <4didnT9jlt_YeCb5nZ2dnZfqnPadnZ2d@brightview.co.uk> at Sat, 22
Jul 2023 15:18:44, NY <me@privacy.net> writes
[]
The ultimate *visible* RFI was on the news reports from the warships in
the Falklands War. To begin with, the reports were always preceded by an >>apology for the poor picture quality - because the ship's rotating radar >>pulse stomped a great big noise bar over the picture every couple of >>seconds. Of course film would have been immune but there would have been >>the "little" problem of taking a film-processing system and telecine ;-)
ENG cameras have to be immune to all *normal* RFI, but immunity from a >>megawatt of SHF from a radar wouldn't have been tested for ;-)
Don't know whether it affected the electronics as such (amplifiers etc) or >>whether it buggered up the electron beams inside the plumbicon tubes - >>because the early 80s were almost certainly before solid-state sensors.
I always assumed it got into the electronics, rather than directly
affecting the light sensor(s) [of whatever sort].
It did occur to me that the patterning might be giving away the structure
of the radar pulses - they obviously weren't just a type A radar, but a digitally-complex pulse - to anyone seeing it, but presumably either this wasn't thought of, it was thought to be not important, or the structure
was ever-changing and such analysis was pointless.
--
J. P. Gilliver. UMRA: 1960/<1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf
Speed has never killed anyone. Suddenly becoming stationary, that's what
gets
you. - Jeremy Clarkson, Top Gear
On 22/07/2023 11:45, Brian Gaff wrote:
I'm sure we tried that as well. It worked on a tape recorder, but not on
other things. Indeed, those with long memories will recall the Sinclair
IC12
amplifier chips. I built a couple of these for stereo in my little
bedroom
when I was younger. They persistently picked up radar pulses from the
industrial estate down the road. Scanning for these put them in between
band
4 and 5 where videos used to live as well. Nothing else was picked up. I
had
to replace one due to a short in the speaker blowing it up and it was
then
made by Texas and still had the same problem, but later on making the
power
section use ILP modules got rid of it. One has to imagine that the IC was
i
n fact a glorified op amp of course, and had many more transistors in a
very
small area than you needed for the gain you used, so many more chances to
pick up crud.
The ultimate *visible* RFI was on the news reports from the warships in
the Falklands War. To begin with, the reports were always preceded by an apology for the poor picture quality - because the ship's rotating radar pulse stomped a great big noise bar over the picture every couple of
seconds. Of course film would have been immune but there would have been
the "little" problem of taking a film-processing system and telecine ;-)
ENG cameras have to be immune to all *normal* RFI, but immunity from a megawatt of SHF from a radar wouldn't have been tested for ;-)
Don't know whether it affected the electronics as such (amplifiers etc) or whether it buggered up the electron beams inside the plumbicon tubes - because the early 80s were almost certainly before solid-state sensors.
In article <4didnT9jlt_YeCb5nZ2dnZfqnPadnZ2d@brightview.co.uk>, NY <me@privacy.net> scribeth thus
On 22/07/2023 11:45, Brian Gaff wrote:
I'm sure we tried that as well. It worked on a tape recorder, but not on >>> other things. Indeed, those with long memories will recall the Sinclair
IC12
amplifier chips. I built a couple of these for stereo in my little
bedroom
when I was younger. They persistently picked up radar pulses from the
industrial estate down the road. Scanning for these put them in between
band
4 and 5 where videos used to live as well. Nothing else was picked up. I >>> had
to replace one due to a short in the speaker blowing it up and it was
then
made by Texas and still had the same problem, but later on making the
power
section use ILP modules got rid of it. One has to imagine that the IC
was i
n fact a glorified op amp of course, and had many more transistors in a
very
small area than you needed for the gain you used, so many more chances
to
pick up crud.
The ultimate *visible* RFI was on the news reports from the warships in
the Falklands War. To begin with, the reports were always preceded by an >>apology for the poor picture quality - because the ship's rotating radar >>pulse stomped a great big noise bar over the picture every couple of >>seconds. Of course film would have been immune but there would have been >>the "little" problem of taking a film-processing system and telecine ;-)
ENG cameras have to be immune to all *normal* RFI, but immunity from a >>megawatt of SHF from a radar wouldn't have been tested for ;-)
Don't know whether it affected the electronics as such (amplifiers etc)
or whether it buggered up the electron beams inside the plumbicon tubes
- because the early 80s were almost certainly before solid-state sensors.
Wasn't their a tale of some incoming missile not being spotted as a
radar was tuned off whilst communicating with London?..
--
Tony Sayer
Man is least himself when he talks in his own person.
Give him a keyboard, and he will reveal himself.
On Sat, 22 Jul 2023 15:18:44 +0100, NY wrote:
The ultimate *visible* RFI was on the news reports from the warships in
the Falklands War. To begin with, the reports were always preceded by an
apology for the poor picture quality - because the ship's rotating radar
pulse stomped a great big noise bar over the picture every couple of
seconds. Of course film would have been immune but there would have been
the "little" problem of taking a film-processing system and telecine ;-)
Sometime around the late '60s or early 70s I was recording on 2" quad VTR
for ABC of America the arrival of Richard Nixon at Heathrow from a feed of
a BBC OB unit, but as Air Force One came in to land it's anti-missile
defence electronics completely wiped out the Beeb's microwave link and we lost the picture.
--
TOJ.
In article <u9h8vv$3tlcm$1@dont-email.me>, The Other John
<nomail@home.org>
wrote:
On Sat, 22 Jul 2023 15:18:44 +0100, NY wrote:
The ultimate *visible* RFI was on the news reports from the warships in
the Falklands War. To begin with, the reports were always preceded by
an apology for the poor picture quality - because the ship's rotating
radar pulse stomped a great big noise bar over the picture every couple
of seconds. Of course film would have been immune but there would have
been the "little" problem of taking a film-processing system and
telecine ;-)
Sometime around the late '60s or early 70s I was recording on 2" quad VTR
for ABC of America the arrival of Richard Nixon at Heathrow from a feed
of a BBC OB unit, but as Air Force One came in to land it's anti-missile
defence electronics completely wiped out the Beeb's microwave link and
we lost the picture.
I managed to avoid a RFI problem whm in the early '90s the Russian leader
was due to visit Chequers to meet our PM. The uplink frequency the
Russians wanted to use was slap in the middle of BBC 2 from Oxford - so I said "no".
--
from KT24 in Surrey, England - sent from my RISC OS 4té
"I'd rather die of exhaustion than die of boredom" Thomas Carlyle
On Wed, 19 Jul 2023 09:44:36 +0100, Brian Gaff wrote:
I have an amplified Sub woofer, but it seems to be very prone to picking
stuff up. For example, it can pick up switching transients and up until
quite recently, even Radio China International. The Chinese seem to have
lowered their power recently, but back when I first got it, you could
hear Vatican Radio as well, but these days they don't use short waves.
Its interesting to note it does not pick up Premier radio, even though
there is an am outlet less than a mile away.
We tried mains filters internal capacitors everywhere with no effect.
It
even did it connected just to the mains and no inputs. I can only deduce
that the power amp design is just wide open and allows most stuff into
the amp where it just gets rectified and shoved out through the speaker.
I once had a Tandberg tuner amp that was like this, and no amount of
suppression would work there either.
Brian
I built a Mullard 5-10 many years ago and that picked up all sorts of
stray stations, with a bit of wire on the input. The EF86 was quite sensitive.
On Wed, 19 Jul 2023 09:44:36 +0100, Brian Gaff wrote:[]
I have an amplified Sub woofer, but it seems to be very prone to picking
stuff up. For example, it can pick up switching transients and up until
On Wed, 19 Jul 2023 09:44:36 +0100, Brian Gaff wrote:[]
I have an amplified Sub woofer, but it seems to be very prone to picking >>> stuff up. For example, it can pick up switching transients and up until
I've been very puzzled throughout this thread: surely a sub-woofer
should be pretty low pass? Or is it really an amplified system that _includes_ a sub-woofer, but mid and high range too?
On 22/07/2023 16:31, Woody wrote:
The lads at Pye Cambridge Service at Arbury Road cured it with some ease
- they wrapped the 'electronic ignition' plastic box in (grounded)
cooking foil. 100% instant cure!
I wonder whether a similar might worked with the cameras on the
Falklands warships - wrap camera (except lens) in aluminium foil
connected to ship's metal structure (ie earthed/'watered' hull).
On 23/07/2023 12:05, J. P. Gilliver wrote:
On Wed, 19 Jul 2023 09:44:36 +0100, Brian Gaff wrote:[]
I have an amplified Sub woofer, but it seems to be very prone to
picking
stuff up. For example, it can pick up switching transients and up until
I've been very puzzled throughout this thread: surely a sub-woofer
should be pretty low pass? Or is it really an amplified system that
_includes_ a sub-woofer, but mid and high range too?
The usual design uses a standard amplifier of the appropriate power
rating, a high pass filter for the pass through to the main speakers and a low pass for the feed to the sub. (In effect, a low power version of the crossover found in multi cone speakers). It's cheaper than designing and building an amplifier that has the low pass filter integral to the design.
If wanted, it's easy enough to add the occasional capacitor to reduce HF pickup in an analogue amplifier.
My sub, though, had a class D amplifier, which is not so easy to add filtering to in the design.
--
Tciao for Now!
John.
I managed to avoid a RFI problem whm in the early '90s the Russian leader was due to visit Chequers to meet our PM. The uplink frequency the
Russians wanted to use was slap in the middle of BBC 2 from Oxford - so I said "no".
--
from KT24 in Surrey, England - sent from my RISC OS 4té
In article <4didnT9jlt_YeCb5...@brightview.co.uk>, NY
<m...@privacy.net> wrote:
On 22/07/2023 11:45, Brian Gaff wrote:
I'm sure we tried that as well. It worked on a tape recorder, but not
on other things. Indeed, those with long memories will recall the Sinclair IC12 amplifier chips. I built a couple of these for stereo in
my little bedroom when I was younger. They persistently picked up radar pulses from the industrial estate down the road. Scanning for these put them in between band 4 and 5 where videos used to live as well. Nothing else was picked up. I had to replace one due to a short in the speaker blowing it up and it was then made by Texas and still had the same problem, but later on making the power section use ILP modules got rid
of it. One has to imagine that the IC was i n fact a glorified op amp
of course, and had many more transistors in a very small area than you needed for the gain you used, so many more chances to pick up crud.
The ultimate *visible* RFI was on the news reports from the warships in
the Falklands War. To begin with, the reports were always preceded by an apology for the poor picture quality - because the ship's rotating radar pulse stomped a great big noise bar over the picture every couple of seconds. Of course film would have been immune but there would have been the "little" problem of taking a film-processing system and telecine ;-)
ENG cameras have to be immune to all *normal* RFI, but immunity from a megawatt of SHF from a radar wouldn't have been tested for ;-)
Don't know whether it affected the electronics as such (amplifiers etc)This also happened on the Apollo splashdowns. Cameras on a US aircraft carrier
or whether it buggered up the electron beams inside the plumbicon tubes
- because the early 80s were almost certainly before solid-state sensors.
It used to happen anywhere near Filton and over a lot of N Yorks near Fylingdales, if a masthead amp was in use.
They put a camera near for general views of Ben Nevis but had loads of intereference from our Band I transmitter.When HTV built their new studio centre at Culverhouse Cross in 1984, it
On 25/07/2023 01:53, wrightsaerials@aol.com wrote:
It used to happen anywhere near Filton and over a lot of N Yorks near
Fylingdales, if a masthead amp was in use.
When you visit Fylingdales you are warned not to lock your car because
of the number of people who find their car's remote locking is jammed by
the RF levels.
On Saturday, 22 July 2023 at 20:45:06 UTC+1, charles wrote:
I managed to avoid a RFI problem whm in the early '90s the Russian leader
was due to visit Chequers to meet our PM. The uplink frequency the
Russians wanted to use was slap in the middle of BBC 2 from Oxford - so I
said "no".
--
from KT24 in Surrey, England - sent from my RISC OS 4té
During either the World Student Games or the Special Olympics at Sheffield (I can't remember which) the BBC OB outfit had some sort of intercom that worked on the same frequency as BBC1 from Crosspool.
Bill
On 22/07/2023 16:39, MB wrote:
They put a camera near for general views of Ben Nevis but had loads of intereference from our Band I transmitter.When HTV built their new studio centre at Culverhouse Cross in 1984, it
was only a mile or so from Wenvoe. The RF levels from Wenvoe's Band I transmitter on the site were were so high, they had to build the
technical areas in Faraday Cages. Of course, Band I TV ceased in
January 1985, so it wasn't required for very long.
On Mon, 24 Jul 2023 18:00:35 -0700 (PDT), "wrightsaerials@aol.com" <wrightsaerials@f2s.com> wrote:
On Saturday, 22 July 2023 at 20:45:06 UTC+1, charles wrote:
I managed to avoid a RFI problem whm in the early '90s the Russian
leader was due to visit Chequers to meet our PM. The uplink frequency
the Russians wanted to use was slap in the middle of BBC 2 from
Oxford - so I said "no". -- from KT24 in Surrey, England - sent from
my RISC OS 4té
During either the World Student Games or the Special Olympics at
Sheffield (I can't remember which) the BBC OB outfit had some sort of >intercom that worked on the same frequency as BBC1 from Crosspool.
Bill
Many years ago when I lived in Putney, the cluster of vehicles the BBC
set up for the boat race was by the river at the end of our road. Their talkback channel was FM, if I remember correctly at about 92.5MHz, but certainly in the middle of the broadcast band.
I didn't listen to much of it though, as it was too much like being at
work.
Rod.
at BBC TV Centre, if you connected a set of headphones across the
ststion 50v battery, you couuld hear The Light Programme from Brookmans
Park.
On Mon, 24 Jul 2023 18:00:35 -0700 (PDT), "wrightsaerials@aol.com" <wrightsaerials@f2s.com> wrote:
On Saturday, 22 July 2023 at 20:45:06 UTC+1, charles wrote:
I managed to avoid a RFI problem whm in the early '90s the Russian leader >> was due to visit Chequers to meet our PM. The uplink frequency the
Russians wanted to use was slap in the middle of BBC 2 from Oxford - so I >> said "no".
--
from KT24 in Surrey, England - sent from my RISC OS 4té
During either the World Student Games or the Special Olympics at
Sheffield (I can't remember which) the BBC OB outfit had some sort of >intercom that worked on the same frequency as BBC1 from Crosspool.
Bill
Many years ago when I lived in Putney, the cluster of vehicles the BBC
set up for the boat race was by the river at the end of our road.
Their talkback channel was FM, if I remember correctly at about
92.5MHz, but certainly in the middle of the broadcast band.
I didn't listen to much of it though, as it was too much like being at
work.
charles <charles@candehope.me.uk> wrote:
[...]
at BBC TV Centre, if you connected a set of headphones across the ststion 50v battery, you couuld hear The Light Programme from Brookmans Park.
Only for a few seconds, I suppose - then your ears began to cook.
50v across 600 ohms = 4 watts.
at BBC TV Centre, if you connected a set of headphones across the ststion
50v battery, you couuld hear The Light Programme from Brookmans Park.
In article <1qefm06.m4ixt41btb4s4N%liz@poppyrecords.invalid.invalid>,
Liz Tuddenham <liz@poppyrecords.invalid.invalid> wrote:
charles <charles@candehope.me.uk> wrote:
[...]
at BBC TV Centre, if you connected a set of headphones across the ststion 50v battery, you couuld hear The Light Programme from Brookmans Park.
Only for a few seconds, I suppose - then your ears began to cook.
50v across 600 ohms = 4 watts.
but, if you had a capacitor in the path, there'd be no DC flow.
charles <charles@candehope.me.uk> wrote:
In article <1qefm06.m4ixt41btb4s4N%liz@poppyrecords.invalid.invalid>,
Liz Tuddenham <liz@poppyrecords.invalid.invalid> wrote:
charles <charles@candehope.me.uk> wrote:
[...]
at BBC TV Centre, if you connected a set of headphones across the ststion
50v battery, you couuld hear The Light Programme from Brookmans Park.
Only for a few seconds, I suppose - then your ears began to cook.
50v across 600 ohms = 4 watts.
but, if you had a capacitor in the path, there'd be no DC flow.
Nobody mentioned one.
In article <1qeftw3.1pmhnptl41w7eN%liz@poppyrecords.invalid.invalid>,
Liz Tuddenham <liz@poppyrecords.invalid.invalid> wrote:
charles <charles@candehope.me.uk> wrote:
In article <1qefm06.m4ixt41btb4s4N%liz@poppyrecords.invalid.invalid>,
Liz Tuddenham <liz@poppyrecords.invalid.invalid> wrote:
charles <charles@candehope.me.uk> wrote:
[...]
at BBC TV Centre, if you connected a set of headphones across the ststion >>>>> 50v battery, you couuld hear The Light Programme from Brookmans Park.
Only for a few seconds, I suppose - then your ears began to cook.
50v across 600 ohms = 4 watts.
but, if you had a capacitor in the path, there'd be no DC flow.
Nobody mentioned one.
True, but who'd be silly enough to put a set of cans directly across a 50v battery
On 25/07/2023 19:30, charles wrote:
True, but who'd be silly enough to put a set of cans directly across a
50v
battery
I don't see the problem if they are high impedance.
In article <1qeftw3.1pmhnptl41w7eN%liz@poppyrecords.invalid.invalid>,
Liz Tuddenham <liz@poppyrecords.invalid.invalid> wrote:
charles <charles@candehope.me.uk> wrote:
In article <1qefm06.m4ixt41btb4s4N%liz@poppyrecords.invalid.invalid>,
Liz Tuddenham <liz@poppyrecords.invalid.invalid> wrote:
charles <charles@candehope.me.uk> wrote:
[...]
at BBC TV Centre, if you connected a set of headphones across the ststion 50v battery, you couuld hear The Light Programme from Brookmans Park.
Only for a few seconds, I suppose - then your ears began to cook.
50v across 600 ohms = 4 watts.
but, if you had a capacitor in the path, there'd be no DC flow.
Nobody mentioned one.
True, but who'd be silly enough to put a set of cans directly across a 50v battery
On 25/07/2023 19:30, charles wrote:
In article <1qeftw3.1pmhnptl41w7eN%liz@poppyrecords.invalid.invalid>,
Liz Tuddenham <liz@poppyrecords.invalid.invalid> wrote:
charles <charles@candehope.me.uk> wrote:
In article <1qefm06.m4ixt41btb4s4N%liz@poppyrecords.invalid.invalid>,
Liz Tuddenham <liz@poppyrecords.invalid.invalid> wrote:
charles <charles@candehope.me.uk> wrote:
[...]
at BBC TV Centre, if you connected a set of headphones across the
ststion 50v battery, you couuld hear The Light Programme from
Brookmans Park.
Only for a few seconds, I suppose - then your ears began to cook.
50v across 600 ohms = 4 watts.
but, if you had a capacitor in the path, there'd be no DC flow.
Nobody mentioned one.
True, but who'd be silly enough to put a set of cans directly across a 50v battery
I don't see the problem if they are high impedance.
at BBC TV Centre, if you connected a set of headphones across the ststion
50v battery, you couuld hear The Light Programme from Brookmans Park.
Many people do not realise that Fylingdales and its associates work in
the 420-450MHz band*: car keys used to use 433.92MHz (right in the
middle of the 70cms amateur radio band of 430-440MHz) but many now use frequencies in the 860MHz area.
Fylingdales was not so much of a problem. When the emergency services
started using Airwave at 380/390MHz and digital the number of calls to
the AA from drivers unable to get into their cars at Heathrow
sky-rocketed. The aerials were placed on the roof of the car parks to
give better coverage for car theft but it seemed to occur to no-one that
the increased noise floor could affect keyless car entry!
When HTV built their new studio centre at Culverhouse Cross in 1984, it
was only a mile or so from Wenvoe. The RF levels from Wenvoe's Band I transmitter on the site were were so high, they had to build the
technical areas in Faraday Cages. Of course, Band I TV ceased in
January 1985, so it wasn't required for very long.
On 25/07/2023 08:47, Mark Carver wrote:
When HTV built their new studio centre at Culverhouse Cross in 1984, it
was only a mile or so from Wenvoe. The RF levels from Wenvoe's Band I transmitter on the site were were so high, they had to build the
technical areas in Faraday Cages. Of course, Band I TV ceased in
January 1985, so it wasn't required for very long.
I was told some time ago that Marks and Spencers had to spend a lot on protecting their store near Lisnagarvey from the effects of RF.
If I had been a broadcaster putting out a huge, but legal, signal and
nearby buildings were saturated, would I be legally responsible for mitigating the nuisance?
On 25/07/2023 09:07, Woody wrote:
Many people do not realise that Fylingdales and its associates work in
the 420-450MHz band*: car keys used to use 433.92MHz (right in the
middle of the 70cms amateur radio band of 430-440MHz) but many now use
frequencies in the 860MHz area.
Fylingdales was not so much of a problem. When the emergency services
started using Airwave at 380/390MHz and digital the number of calls to
the AA from drivers unable to get into their cars at Heathrow
sky-rocketed. The aerials were placed on the roof of the car parks to
give better coverage for car theft but it seemed to occur to no-one that
the increased noise floor could affect keyless car entry!
I asked at Fylingdales what frequency it operated on and was told it was secret! Obviously never heard of scanners or spectrum analysers.
With those levels of RF, the frequency is probably irrelevant with most receivers.
There used to be remote car keys operating on a lot of different
frequencies (one of our vehicles at work had an illegal one!). But
probably not a problem now that most are factory fitted.
"MB" <MB@nospam.net> wrote in message news:u9qfq8$1e4r0$2@dont-email.me...
On 25/07/2023 09:07, Woody wrote:
Many people do not realise that Fylingdales and its associates work in
the 420-450MHz band*: car keys used to use 433.92MHz (right in the
middle of the 70cms amateur radio band of 430-440MHz) but many now use
frequencies in the 860MHz area.
Fylingdales was not so much of a problem. When the emergency services
started using Airwave at 380/390MHz and digital the number of calls to
the AA from drivers unable to get into their cars at Heathrow
sky-rocketed. The aerials were placed on the roof of the car parks to
give better coverage for car theft but it seemed to occur to no-one that >>> the increased noise floor could affect keyless car entry!
I asked at Fylingdales what frequency it operated on and was told it was
secret! Obviously never heard of scanners or spectrum analysers.
With those levels of RF, the frequency is probably irrelevant with most
receivers.
There used to be remote car keys operating on a lot of different
frequencies (one of our vehicles at work had an illegal one!). But
probably not a problem now that most are factory fitted.
The real problem is those cars that have no mechanical keyhole (or else one >that needs tools to access in an emergency), where you can only use the >remote. I'm used to one of my car keys (I keep it as the spare) not
operating the central locking (yes I've replaced its battery!) and so having >to lock/unlock the doors the old-fashioned way when Ii take the car to the >garage to be serviced. And I warn them, though I imagine they are used to >central locking failing for whatever reason and know how to use the key >blade.
And if the RF is so strong that it even affects the key-ECU comms for the >immobiliser, then you are totally stuffed. I presume the only way around
that is to tow the car far enough away that the key and immobiliser can talk >and so negotiate to enable the engine.
What is the legal situation if equipment in an existing building is
affected by a newly-built transmitter?
There's this little story from the era the BBC had an AM transmitter sited at Sutton Coldfield
Begs the question what do the staff at Fylingdales use for transport?,
push bikes?...
In article <u9qtdm$1fit9$1@dont-email.me>, NY <me@privacy.invalid>
scribeth thus
"MB" <MB@nospam.net> wrote in message news:u9qfq8$1e4r0$2@dont-email.me... >> On 25/07/2023 09:07, Woody wrote:
Many people do not realise that Fylingdales and its associates work in >>> the 420-450MHz band*: car keys used to use 433.92MHz (right in the
middle of the 70cms amateur radio band of 430-440MHz) but many now use >>> frequencies in the 860MHz area.
Fylingdales was not so much of a problem. When the emergency services
started using Airwave at 380/390MHz and digital the number of calls to >>> the AA from drivers unable to get into their cars at Heathrow
sky-rocketed. The aerials were placed on the roof of the car parks to
give better coverage for car theft but it seemed to occur to no-one that >>> the increased noise floor could affect keyless car entry!
I asked at Fylingdales what frequency it operated on and was told it was >> secret! Obviously never heard of scanners or spectrum analysers.
With those levels of RF, the frequency is probably irrelevant with most
receivers.
There used to be remote car keys operating on a lot of different
frequencies (one of our vehicles at work had an illegal one!). But
probably not a problem now that most are factory fitted.
The real problem is those cars that have no mechanical keyhole (or else one >that needs tools to access in an emergency), where you can only use the >remote. I'm used to one of my car keys (I keep it as the spare) not >operating the central locking (yes I've replaced its battery!) and so having >to lock/unlock the doors the old-fashioned way when Ii take the car to the >garage to be serviced. And I warn them, though I imagine they are used to >central locking failing for whatever reason and know how to use the key >blade.
And if the RF is so strong that it even affects the key-ECU comms for the >immobiliser, then you are totally stuffed. I presume the only way around >that is to tow the car far enough away that the key and immobiliser can talk >and so negotiate to enable the engine.
Begs the question what do the staff at Fylingdales use for transport?,
push bikes?...
In message <tMg4NvA6ZSwkFwui@bancom.co.uk> at Wed, 26 Jul 2023 14:58:18,
tony sayer <tony@bancom.co.uk> writes
[]
Begs the question what do the staff at Fylingdales use for transport?,Not the same question, but I remember hearing/seeing somewhere that at certain oil (gas?) refinery sites, conventional vehicles were not allowed, especially diesel ones, because the air was sufficiently flammable that
push bikes?...
even if you turned the ignition off, the engine would race, to the extent
of flames coming out of the exhaust; vehicles for use on the site had to
be modified in some way.
"J. P. Gilliver" <G6JPG@255soft.uk> wrote in message news:kukPjzebWVwkFw9J@255soft.uk...
In message <tMg4NvA6ZSwkFwui@bancom.co.uk> at Wed, 26 Jul 2023
14:58:18, tony sayer <tony@bancom.co.uk> writes
[]
Begs the question what do the staff at Fylingdales use for transport?,Not the same question, but I remember hearing/seeing somewhere that at
push bikes?...
certain oil (gas?) refinery sites, conventional vehicles were not
allowed, especially diesel ones, because the air was sufficiently
flammable that even if you turned the ignition off, the engine would
race, to the extent of flames coming out of the exhaust; vehicles for
use on the site had to be modified in some way.
I saw a TV programme (maybe Michael Portillo's railway programme) where
the presenter was taken into an underground tunnel somewhere, and he was
told that the only cars that were allowed underground in the tunnels
were diesel ones, because petrol engines were too likely to generate a
spark that could ignite flammable fumes,
I saw a TV programme (maybe Michael Portillo's railway programme) where the presenter was taken into an underground tunnel somewhere, and he was told that the only cars that were allowed underground in the tunnels were diesel ones, because petrol engines were too likely to generate a spark that could ignite flammable fumes,
On 27/07/2023 11:17, NY wrote:
"J. P. Gilliver" <G6JPG@255soft.uk> wrote in message
news:kukPjzebWVwkFw9J@255soft.uk...
In message <tMg4NvA6ZSwkFwui@bancom.co.uk> at Wed, 26 Jul 2023
14:58:18, tony sayer <tony@bancom.co.uk> writes
[]
Begs the question what do the staff at Fylingdales use for transport?, >>>>Not the same question, but I remember hearing/seeing somewhere that at
push bikes?...
certain oil (gas?) refinery sites, conventional vehicles were not
allowed, especially diesel ones, because the air was sufficiently
flammable that even if you turned the ignition off, the engine would
race, to the extent of flames coming out of the exhaust; vehicles for
use on the site had to be modified in some way.
I saw a TV programme (maybe Michael Portillo's railway programme) where
the presenter was taken into an underground tunnel somewhere, and he was
told that the only cars that were allowed underground in the tunnels
were diesel ones, because petrol engines were too likely to generate a
spark that could ignite flammable fumes,
If they develop a leak, petrol is also far easier to ignite than diesel.
It would be interesting to know if battery vehicles are allowed, I was
told a few days ago of another one exploding and it being hushed up.
"John Williamson" <johnwilliamson@btinternet.com> wrote in message >news:kiev3qFbe6tU1@mid.individual.net...(Recent almost manic coverage of e-bike fires has obviously generated
On 27/07/2023 11:17, NY wrote:
"J. P. Gilliver" <G6JPG@255soft.uk> wrote in message
news:kukPjzebWVwkFw9J@255soft.uk...
In message <tMg4NvA6ZSwkFwui@bancom.co.uk> at Wed, 26 Jul 2023
14:58:18, tony sayer <tony@bancom.co.uk> writes
[]
Begs the question what do the staff at Fylingdales use for transport?, >>>>>
push bikes?...
Not the same question, but I remember hearing/seeing somewhere that at >>>> certain oil (gas?) refinery sites, conventional vehicles were not
allowed, especially diesel ones, because the air was sufficiently
flammable that even if you turned the ignition off, the engine would
race, to the extent of flames coming out of the exhaust; vehicles for
use on the site had to be modified in some way.
I saw a TV programme (maybe Michael Portillo's railway programme) where
the presenter was taken into an underground tunnel somewhere, and he was >>> told that the only cars that were allowed underground in the tunnels
were diesel ones, because petrol engines were too likely to generate a
spark that could ignite flammable fumes,
[Interesting story snipped]
If they develop a leak, petrol is also far easier to ignite than diesel.
Too right.
In message <tMg4NvA6ZSwkFwui@bancom.co.uk> at Wed, 26 Jul 2023 14:58:18,
tony sayer <tony@bancom.co.uk> writes
[]
Begs the question what do the staff at Fylingdales use for transport?,
push bikes?...
Not the same question, but I remember hearing/seeing somewhere that at certain oil (gas?) refinery sites, conventional vehicles were not
allowed, especially diesel ones, because the air was sufficiently
flammable that even if you turned the ignition off, the engine would
race, to the extent of flames coming out of the exhaust; vehicles for
use on the site had to be modified in some way.
On 27/07/2023 11:17, NY wrote:
I saw a TV programme (maybe Michael Portillo's railway programme) where the >> presenter was taken into an underground tunnel somewhere, and he was told
that the only cars that were allowed underground in the tunnels were diesel >> ones, because petrol engines were too likely to generate a spark that could >> ignite flammable fumes,
That is quite common.
We had a contract at an underground power station which involved a
drive down a tunnel. Petrol vehicles were not allowed and any
combustibles in the vehicle had to be declared.
All vehicles were parked facing outwards with keys inside.
There was a tally board and in the event of an alarm you would be put
in vehicles and taken out. In the event of a high level alarm, you
could use any vehicle and GET OUT!
It would be interesting to know if battery vehicles are allowed, I was
told a few days ago of another one exploding and it being hushed up.
It would be interesting to know if battery vehicles are allowed, I was
told a few days ago of another one exploding and it being hushed up.
I think that would be Dinorwic (or is it -wig?) pumped storage plant in
a Welsh mountain
But should something break, the
chambers inside the mountain would fill with water_very_ fast, hence
the need for a swift escape.
On 27/07/2023 16:12, J. P. Gilliver wrote:
But should something break, the
chambers inside the mountain would fill with water_very_Â fast, hence
the need for a swift escape.
We were told that someone had worked out how quickly it would fill with
water is a pipe failed (they are *BIG* pipes!).
There would be no hope of escape, it would fill much too fast.
Yes well nowadays you would not get away with this, but some of the Russian space communication some years ago was in the middle of band 3. You could when in range, clearly hear them talking and joking in mostly Russian but some English.
Brian
There used to be studio talkback on narrow-band FM from the Mendip transmitter mast, presumably for the benefit of roving OB units. It was entertaining listening to the rehearsals for the evening local
television news - especially when a lady announcer's mic became
unclipped and it had to be retrieved.
I seem to remember the transmission was around 175 Mc/s, but I may be mistaken.
On Thu 27/07/2023 19:40, MB wrote:[]
On 27/07/2023 16:12, J. P. Gilliver wrote:
But should something break, theWe were told that someone had worked out how quickly it would fill
chambers inside the mountain would fill with water_very_ fast, hence
the need for a swift escape.
with water is a pipe failed (they are *BIG* pipes!).
There would be no hope of escape, it would fill much too fast.
In theory if all six units were spinning on air (as they would be just
before the adverts in the latest James Bond film being shown on TV and
a cuppa would be needed) they could go from 0 to 1320MW in 10.4
seconds. Conversely a demand stop would take them from 1320MW to zero
in a little over 4 seconds BUT the catch pond (about the size of the
old Wembley Stadium) at the top of the main 525ft drop shaft would fill
in less than 10 seconds from a shaft of water 30m across and
theoretically over 50m high - but I don't think they ever tried it. The
They generate at 11KV and about 18500A but there is a 275KV sub-station >inside the mountain which takes the power away in water-cooled pipes
about 9 miles before going overhead. The whole place can be controlled >locally by three shift staff, or remotely from Connah's Quay on Deeside.
It is now known as 'Electric Mountain.' A TV (slightly
anti-nuclear/Thatcher) drama called Edge of Darkness starring Bob Peck
had large sections (allegedly Aldermaston) filmed inside Dinorwic in
1985. It was repeated (for the first time?) earlier this year.
Is it open to the public? Sounds like it'd be quite interesting to visit
(for those of us of an engineering bent).
When on the South coast or Isle of Wight we could sometimes hear the
same kind of thing for BBC South on, if I remember correctly exactly 141MHz.
On 28/07/2023 03:59, J. P. Gilliver wrote:
Is it open to the public? Sounds like it'd be quite interesting to visit (for those of us of an engineering bent).
Cruachan has a visitor centre with exhibition and cafe - with Pine
Martens regularly seen outside eating scraps.
You can then be taken to a viewing gallery at the end of the tunnel
where you can see the generators. We got to into the generator hall and control room - fortunately none were running so it was quiet!
You used to be able to borrow the gate key to drive up to the dam but
too many people did not return the kay so they stopped that. We had a
key for access to a site up there so got to drive over the dam.
On 28/07/2023 09:15, charles wrote:
Just after the Torosay transmitter came on air I was in the area carryingout a survey and I stopped at Cruachan, which was new. I got a
look round - free.
It can be a handy place for a coffee in the cafe because not much along there.
Just after the Torosay transmitter came on air I was in the area
carryingout a survey and I stopped at Cruachan, which was new. I got a
look round - free.
There used to be studio talkback on narrow-band FM from the Mendip transmitter mast, presumably for the benefit of roving OB units.
It was entertaining listening to the rehearsals for the evening local television news - especially when a lady announcer's mic became
unclipped and it had to be retrieved.
I seem to remember the transmission was around 175 Mc/s, but I may be mistaken.
On Tue, 25 Jul 2023 16:14:55 +0100, Liz Tuddenham <liz@poppyrecords.invalid.invalid> wrote:
There used to be studio talkback on narrow-band FM from the Mendip transmitter mast, presumably for the benefit of roving OB units.
Yes, that was ours.
It was entertaining listening to the rehearsals for the evening local television news - especially when a lady announcer's mic became
unclipped and it had to be retrieved.
Was it?
I seem to remember the transmission was around 175 Mc/s, but I may be mistaken.
Ch 1 on 141.375 MHz was the one from Mendip. I can't remember the
exact frequency of Ch 2 which was used from other locations, but it was
in the same ball-park.
Ch 1 on 141.375 MHz was the one from Mendip. I can't remember the exact frequency of Ch 2 which was used from other locations, but it was in the
same ball-park.
On 29/07/2023 01:08, Paul Ratcliffe wrote:
Ch 1 on 141.375 MHz was the one from Mendip. I can't remember the
exact frequency of Ch 2 which was used from other locations, but it
was in the same ball-park.
Could it have been that the mobile channels were around 141 MHz and 170
MHz was used for linking back to the base?
On Sat 29/07/2023 16:13, MB wrote:
On 29/07/2023 01:08, Paul Ratcliffe wrote:
Ch 1 on 141.375 MHz was the one from Mendip. I can't remember the
exact frequency of Ch 2 which was used from other locations, but it
was in the same ball-park.
Could it have been that the mobile channels were around 141 MHz and
170 MHz was used for linking back to the base?
IMSMC the long range radio mics as used at, for example, the Grand
National, were around 140-141MHz as noted. Some frequencies in Band IV
and later Band V were also used. Studio radio mics were mostly about
174MHz but when Band IV became available for mobile radio and data
they were shifted onto TV channel 69 (about 860MHz) where they remain
to this day (I think). Interesting that the UK UHF band was 21-69 but
whilst 21 was used (used even more now with DTTV) 69 was never allocated.
The 141 MHz Rx/Tx at Mendip under discussion was radio talkback, (to
allow off air comms between the studio, and the director and presenters
on site at the OB, nothing to do with radio mics. A presenter will often
wear two devices, radio talkback (normally for them rx only to hear the director etc) and radio mic, tx only (for their voice to be heard on
air, and obviously inside the truck, and back at the studio) All that
said, the body worn talkback kit will be low power, and only Rx'ing from
the OB Truck. The radio talkback to and from the studio (via Mendip in
this case) was/still is a different higher power device, using dipoles
or a yagi on the roof of the truck.
Ch 1 on 141.375 MHz was the one from Mendip. I can't remember the
exact frequency of Ch 2 which was used from other locations, but it was
in the same ball-park.
Thanks, I wasn't sure about that.
| Sysop: | Keyop |
|---|---|
| Location: | Huddersfield, West Yorkshire, UK |
| Users: | 297 |
| Nodes: | 16 (2 / 14) |
| Uptime: | 105:42:25 |
| Calls: | 6,660 |
| Calls today: | 2 |
| Files: | 12,209 |
| Messages: | 5,335,315 |