• Re: Radio Reception - Massive Electrical Interference

    From Phil Hobbs@21:1/5 to Chris K-Man on Tue Jul 19 16:08:27 2022
    Chris K-Man wrote:
    Hi!

    I just moved to an apartment and wanted to keep my radio in the bathroom, same as I did in the last place I lived.

    Only problem with this place is that the main electrical drop to the building is right outside my bathroom wall, interfering with FM/AM reception.

    Is there anything I can do to alleviate this - putting a noise filter on the radio power cord, etc??

    Right at the frequency of an AM I've been listening to for years, is a loud combination buzz/screeching sound.


    Maybe a variable-frequency drive for an induction motor in some HVAC
    blower. Those things are super bad news. Or it might just be a whole
    building full of SMPSes.

    Cheers

    Phil Hobbs

    --
    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 Chris K-Man@21:1/5 to All on Tue Jul 19 12:58:52 2022
    Hi!

    I just moved to an apartment and wanted to keep my radio in the bathroom, same as I did in the last place I lived.

    Only problem with this place is that the main electrical drop to the building is right outside my bathroom wall, interfering with FM/AM reception.

    Is there anything I can do to alleviate this - putting a noise filter on the radio power cord, etc??

    Right at the frequency of an AM I've been listening to for years, is a loud combination buzz/screeching sound.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Chris K-Man@21:1/5 to Phil Hobbs on Tue Jul 19 14:00:58 2022
    On Tuesday, July 19, 2022 at 4:08:33 PM UTC-4, Phil Hobbs wrote:
    Chris K-Man wrote:
    Hi!

    I just moved to an apartment and wanted to keep my radio in the bathroom, same as I did in the last place I lived.

    Only problem with this place is that the main electrical drop to the building is right outside my bathroom wall, interfering with FM/AM reception.

    Is there anything I can do to alleviate this - putting a noise filter on the radio power cord, etc??

    Right at the frequency of an AM I've been listening to for years, is a loud combination buzz/screeching sound.

    Maybe a variable-frequency drive for an induction motor in some HVAC
    blower. Those things are super bad news. Or it might just be a whole
    building full of SMPSes.

    Cheers

    Phil Hobbs

    --
    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
    _______

    It happens only to radios brought into this bathroom. Lots of static on FM, intermittent
    multiplex(stereo for the young uns!) and loud static and that buzzy-shriek right below
    80 on the standard dial(AM).

    Once the boombox is moved somewhere else in the apt, it performs like a normal set.

    This is (an example of) what I can see in the upper LH corner of my bathroom window:

    https://i.pinimg.com/originals/2e/3c/ce/2e3cceb1c024f799276a55ab05b44240.png

    A big honkin one, twice the size of a residential service! And the closer a radio set gets
    to that thing, the worse it buzzes

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Chris K-Man@21:1/5 to Phil Hobbs on Tue Jul 19 14:53:22 2022
    On Tuesday, July 19, 2022 at 5:28:18 PM UTC-4, Phil Hobbs wrote:
    Chris K-Man wrote:
    On Tuesday, July 19, 2022 at 4:08:33 PM UTC-4, Phil Hobbs wrote:
    Chris K-Man wrote:
    Hi!

    I just moved to an apartment and wanted to keep my radio in the bathroom, same as I did in the last place I lived.

    Only problem with this place is that the main electrical drop to the building is right outside my bathroom wall, interfering with FM/AM reception.

    Is there anything I can do to alleviate this - putting a noise filter on the radio power cord, etc??

    Right at the frequency of an AM I've been listening to for years, is a loud combination buzz/screeching sound.

    Maybe a variable-frequency drive for an induction motor in some HVAC
    blower. Those things are super bad news. Or it might just be a whole
    building full of SMPSes.

    It happens only to radios brought into this bathroom. Lots of static on FM, intermittent
    multiplex(stereo for the young uns!) and loud static and that buzzy-shriek right below
    80 on the standard dial(AM).

    Once the boombox is moved somewhere else in the apt, it performs like a normal set.

    This is (an example of) what I can see in the upper LH corner of my bathroom window:

    https://i.pinimg.com/originals/2e/3c/ce/2e3cceb1c024f799276a55ab05b44240.png

    A big honkin one, twice the size of a residential service! And the closer a radio set gets
    to that thing, the worse it buzzes

    Well, there's more loop area there to spray magnetic fields around than
    there is in the cables in the wall. The nasty high-frequency currents
    are probably coming from VFDs, switching supplies, and so on.

    I build a lot of sensitive front end amps in instruments, so I feel your pain. You still hear people advocating for star grounds, split ground
    planes, and so on. Those were great in 1950, but in 2022 there's so
    much RF and miscellaneous hash running round that a split ground plane
    is as good as an antenna.(*)

    Cheers

    Phil Hobbs

    (*) There are fairly popular antenna designs based on slots and patches
    in planar conductors.
    _______

    Should an electrical service mast like the one I linked to cause that level of EMI?

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to Chris K-Man on Tue Jul 19 17:28:13 2022
    Chris K-Man wrote:
    On Tuesday, July 19, 2022 at 4:08:33 PM UTC-4, Phil Hobbs wrote:
    Chris K-Man wrote:
    Hi!

    I just moved to an apartment and wanted to keep my radio in the bathroom, same as I did in the last place I lived.

    Only problem with this place is that the main electrical drop to the building is right outside my bathroom wall, interfering with FM/AM reception.

    Is there anything I can do to alleviate this - putting a noise filter on the radio power cord, etc??

    Right at the frequency of an AM I've been listening to for years, is a loud combination buzz/screeching sound.

    Maybe a variable-frequency drive for an induction motor in some HVAC
    blower. Those things are super bad news. Or it might just be a whole
    building full of SMPSes.


    It happens only to radios brought into this bathroom. Lots of static on FM, intermittent
    multiplex(stereo for the young uns!) and loud static and that buzzy-shriek right below
    80 on the standard dial(AM).

    Once the boombox is moved somewhere else in the apt, it performs like a normal set.

    This is (an example of) what I can see in the upper LH corner of my bathroom window:

    https://i.pinimg.com/originals/2e/3c/ce/2e3cceb1c024f799276a55ab05b44240.png

    A big honkin one, twice the size of a residential service! And the closer a radio set gets
    to that thing, the worse it buzzes


    Well, there's more loop area there to spray magnetic fields around than
    there is in the cables in the wall. The nasty high-frequency currents
    are probably coming from VFDs, switching supplies, and so on.

    I build a lot of sensitive front end amps in instruments, so I feel your
    pain. You still hear people advocating for star grounds, split ground
    planes, and so on. Those were great in 1950, but in 2022 there's so
    much RF and miscellaneous hash running round that a split ground plane
    is as good as an antenna.(*)

    Cheers

    Phil Hobbs

    (*) There are fairly popular antenna designs based on slots and patches
    in planar conductors.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Chris K-Man@21:1/5 to Phil Hobbs on Tue Jul 19 14:50:21 2022
    On Tuesday, July 19, 2022 at 5:28:18 PM UTC-4, Phil Hobbs wrote:
    Chris K-Man wrote:
    On Tuesday, July 19, 2022 at 4:08:33 PM UTC-4, Phil Hobbs wrote:
    Chris K-Man wrote:
    Hi!

    I just moved to an apartment and wanted to keep my radio in the bathroom, same as I did in the last place I lived.

    Only problem with this place is that the main electrical drop to the building is right outside my bathroom wall, interfering with FM/AM reception.

    Is there anything I can do to alleviate this - putting a noise filter on the radio power cord, etc??

    Right at the frequency of an AM I've been listening to for years, is a loud combination buzz/screeching sound.

    Maybe a variable-frequency drive for an induction motor in some HVAC
    blower. Those things are super bad news. Or it might just be a whole
    building full of SMPSes.

    It happens only to radios brought into this bathroom. Lots of static on FM, intermittent
    multiplex(stereo for the young uns!) and loud static and that buzzy-shriek right below
    80 on the standard dial(AM).

    Once the boombox is moved somewhere else in the apt, it performs like a normal set.

    This is (an example of) what I can see in the upper LH corner of my bathroom window:

    https://i.pinimg.com/originals/2e/3c/ce/2e3cceb1c024f799276a55ab05b44240.png

    A big honkin one, twice the size of a residential service! And the closer a radio set gets
    to that thing, the worse it buzzes

    Well, there's more loop area there to spray magnetic fields around than
    there is in the cables in the wall. The nasty high-frequency currents
    are probably coming from VFDs, switching supplies, and so on.

    I build a lot of sensitive front end amps in instruments, so I feel your pain. You still hear people advocating for star grounds, split ground
    planes, and so on. Those were great in 1950, but in 2022 there's so
    much RF and miscellaneous hash running round that a split ground plane
    is as good as an antenna.(*)

    Cheers

    Phil Hobbs

    (*) There are fairly popular antenna designs based on slots and patches
    in planar conductors.
    ______________

    The point is, it's an issue, especially at certain parts of the AM dial, when a radio
    is within 10 feet of the service mast outside my bathroom corner window. Outside
    of the bathroom corner of the apt, the interference drops off exponentially.

    On the ground floor is a light-industrial classification, prefabing shower doors and
    such. No loud hums or buzzes every time material is cut or edges chamfered. Nothing
    like that at all. Just a steadily increasing noise the closer one gets to that bathroom
    window. The radio sits on top of a toilet about 8 feet from that corner of the bathroom

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Charles Lucas@21:1/5 to Chris K-Man on Tue Jul 19 14:19:05 2022
    On Tuesday, July 19, 2022 at 4:01:02 PM UTC-5, Chris K-Man wrote:
    On Tuesday, July 19, 2022 at 4:08:33 PM UTC-4, Phil Hobbs wrote:
    Chris K-Man wrote:
    Hi!

    I just moved to an apartment and wanted to keep my radio in the bathroom, same as I did in the last place I lived.

    Only problem with this place is that the main electrical drop to the building is right outside my bathroom wall, interfering with FM/AM reception.

    Is there anything I can do to alleviate this - putting a noise filter on the radio power cord, etc??

    Right at the frequency of an AM I've been listening to for years, is a loud combination buzz/screeching sound.

    Maybe a variable-frequency drive for an induction motor in some HVAC blower. Those things are super bad news. Or it might just be a whole building full of SMPSes.

    Cheers

    Phil Hobbs

    --
    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
    _______

    It happens only to radios brought into this bathroom. Lots of static on FM, intermittent
    multiplex(stereo for the young uns!) and loud static and that buzzy-shriek right below
    80 on the standard dial(AM).

    Once the boombox is moved somewhere else in the apt, it performs like a normal set.

    This is (an example of) what I can see in the upper LH corner of my bathroom window:

    https://i.pinimg.com/originals/2e/3c/ce/2e3cceb1c024f799276a55ab05b44240.png

    A big honkin one, twice the size of a residential service! And the closer a radio set gets
    to that thing, the worse it buzzes

    With Radio reception, you can have architectural interference in a building or a residence
    for a myriad of different reasons. Here, you have electrical power interference as well as
    other metal (including aluminum) which inhibit radio waves from travel through it. If you
    have a table radio or a portable, try moving the device closer to a window or area with open
    air. Since you moved in and the place is new, I take a portable radio (an FM radio) from a
    cell phone or bike radio and walk around to find out where the best reception is. This is
    a trial and error approach. I then due this for AM and see if and where the best reception is
    for AM and FM, what direction the antenna is pointed, how far away, etc...

    I do this to find the best range within the dwelling. I usually add an antenna to the device
    (if it has a telescopic antenna, you can clip additional wire to the top of the antenna with the
    clamp portion of the clip being conduction and the handle being non-conductive), so you can
    get more range and better reception.

    AM is amplitude modulation and the signal is modulated by the height (amplitude) of the
    radio wave. FM is frequency modulated (is wider band than AM) and uses line of sight
    reception. FM is in a higher band than AM. FM is shorter range and more power. AM is
    longer range and less power.

    These concepts apply to the wireless internet as well. Key is a good open area to provide
    an adequate reception envelope. Good Luck and God Bless.

    Sincerely,


    Charles Lucas

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From ehsjr@21:1/5 to Chris K-Man on Tue Jul 19 18:33:52 2022
    On 7/19/2022 5:53 PM, Chris K-Man wrote:
    On Tuesday, July 19, 2022 at 5:28:18 PM UTC-4, Phil Hobbs wrote:
    Chris K-Man wrote:
    On Tuesday, July 19, 2022 at 4:08:33 PM UTC-4, Phil Hobbs wrote:
    Chris K-Man wrote:
    Hi!

    I just moved to an apartment and wanted to keep my radio in the bathroom, same as I did in the last place I lived.

    Only problem with this place is that the main electrical drop to the building is right outside my bathroom wall, interfering with FM/AM reception.

    Is there anything I can do to alleviate this - putting a noise filter on the radio power cord, etc??

    Right at the frequency of an AM I've been listening to for years, is a loud combination buzz/screeching sound.

    Maybe a variable-frequency drive for an induction motor in some HVAC
    blower. Those things are super bad news. Or it might just be a whole
    building full of SMPSes.

    It happens only to radios brought into this bathroom. Lots of static on FM, intermittent
    multiplex(stereo for the young uns!) and loud static and that buzzy-shriek right below
    80 on the standard dial(AM).

    Once the boombox is moved somewhere else in the apt, it performs like a normal set.

    This is (an example of) what I can see in the upper LH corner of my bathroom window:

    https://i.pinimg.com/originals/2e/3c/ce/2e3cceb1c024f799276a55ab05b44240.png

    A big honkin one, twice the size of a residential service! And the closer a radio set gets
    to that thing, the worse it buzzes

    Well, there's more loop area there to spray magnetic fields around than
    there is in the cables in the wall. The nasty high-frequency currents
    are probably coming from VFDs, switching supplies, and so on.

    I build a lot of sensitive front end amps in instruments, so I feel your
    pain. You still hear people advocating for star grounds, split ground
    planes, and so on. Those were great in 1950, but in 2022 there's so
    much RF and miscellaneous hash running round that a split ground plane
    is as good as an antenna.(*)

    Cheers

    Phil Hobbs

    (*) There are fairly popular antenna designs based on slots and patches
    in planar conductors.
    _______

    Should an electrical service mast like the one I linked to cause that level of EMI?

    The mast itself is not the cause. It is a non conductor. It is
    possible there is arcing between the wires inside the mast, but that
    is not the mast causing the problem. If arcing is occurring, it's
    due to frayed insulation on the wires. And I only mention it as a
    possibility, not a diagnosis. Another possibility is corroded/loose
    "bugs" ("utility splices" on your diagram). Again, not a diagnosis,
    but a possibility. But either of those conditions - arcing within
    the mast or bad connections at the top of the mast could make one
    think that the mast is the cause of the problem. Take a portable
    radio to the utility electric meter at the service entrance and see
    what you hear with the radio held near the meter.

    Ed

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Dave Platt@21:1/5 to thekmanrocks@gmail.com on Tue Jul 19 16:04:29 2022
    In article <f3c1f08b-2a62-4f7a-a5d5-e4f31aecaa32n@googlegroups.com>,
    Chris K-Man <thekmanrocks@gmail.com> wrote:

    Should an electrical service mast like the one I linked to cause that level of EMI?

    By itself, no. It ought to be a fairly passive pass-through for AC
    current, with no mechanism for generating RFI. If there's a loose wire
    or other bad connection, it could be making noise (and possibly overheating
    and creating a safety hazard).

    Seems to me there are two possible sources of the RFI you are suffering:

    (1) Industrial equipment on that line (welders, big brush motors,
    switching power supplies) which are generating RFI internally and
    feeding it back into the mains. Here in the US, "Class A" equipment
    (for use in business environments) is allowed a lot more RFI leakage
    than "Class B" (residential), and industrial equipment is even worse.

    (2) A physical fault in the mains wiring, which is causing arcing and
    sparking, corona discharge, and so forth. Two fairly common problems
    on power distribution poles are bad insulators (with electricity
    arcing over them) and loose or defective ground connections. Arcing
    in a circuit-breaker panel (e.g. a breaker going bad) could have
    a similar effect.

    In both cases the noise can travel quite a long distance along power
    wiring to the point where it troubles you.

    There are a few ways that can be used to track the location of a noise
    source or fault of this type. Corona discharges and arcs often
    generate a lot of ultrasonic noise, and there are ultrasound receivers
    with directional microphones which shift this noise down into the
    audible band. Arcing and corona can also generate noise up into the
    VHF band which can be tracked using a receiver and a directional
    antenna (e.g. a small hand-held Yagi). A spectrum analyzer hooked to
    a directional antenna can be a useful tool as you may be able to see
    specific noise lines bouncing up and down.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Chris K-Man@21:1/5 to Dave Platt on Tue Jul 19 16:12:18 2022
    On Tuesday, July 19, 2022 at 7:04:47 PM UTC-4, Dave Platt wrote:
    In article <f3c1f08b-2a62-4f7a...@googlegroups.com>,
    Chris K-Man <thekma...@gmail.com> wrote:

    Should an electrical service mast like the one I linked to cause that level of EMI?
    By itself, no. It ought to be a fairly passive pass-through for AC
    current, with no mechanism for generating RFI. If there's a loose wire
    or other bad connection, it could be making noise (and possibly overheating and creating a safety hazard).

    Seems to me there are two possible sources of the RFI you are suffering:

    (1) Industrial equipment on that line (welders, big brush motors,
    switching power supplies) which are generating RFI internally and
    feeding it back into the mains. Here in the US, "Class A" equipment
    (for use in business environments) is allowed a lot more RFI leakage
    than "Class B" (residential), and industrial equipment is even worse.

    (2) A physical fault in the mains wiring, which is causing arcing and sparking, corona discharge, and so forth. Two fairly common problems
    on power distribution poles are bad insulators (with electricity
    arcing over them) and loose or defective ground connections. Arcing
    in a circuit-breaker panel (e.g. a breaker going bad) could have
    a similar effect.

    In both cases the noise can travel quite a long distance along power
    wiring to the point where it troubles you.

    There are a few ways that can be used to track the location of a noise
    source or fault of this type. Corona discharges and arcs often
    generate a lot of ultrasonic noise, and there are ultrasound receivers
    with directional microphones which shift this noise down into the
    audible band. Arcing and corona can also generate noise up into the
    VHF band which can be tracked using a receiver and a directional
    antenna (e.g. a small hand-held Yagi). A spectrum analyzer hooked to
    a directional antenna can be a useful tool as you may be able to see
    specific noise lines bouncing up and down.
    ____________________
    But close to that mast, in this apartment's bathroom, is where the interference is strongest, out to perhaps a ten foot radius, which covers most of this bathroom. Beyond that, the interference is, at worst, negligible.

    And I understand that the head of the service mast - the part visible above and to the left of the bathroom window, is only part of the package. I will take outside
    a small portable radio, and walk around within 8 feet of the meters at the base of
    the service mast, and see what happens at the frequency of the AM station I listen
    to.

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Jeff Liebermann@21:1/5 to thekmanrocks@gmail.com on Tue Jul 19 21:55:03 2022
    On Tue, 19 Jul 2022 16:12:18 -0700 (PDT), Chris K-Man
    <thekmanrocks@gmail.com> wrote:

    And I understand that the head of the service mast - the part visible above and
    to the left of the bathroom window, is only part of the package. I will take outside
    a small portable radio, and walk around within 8 feet of the meters at the base of
    the service mast, and see what happens at the frequency of the AM station I listen
    to.

    Nice job deducing the likely point of entry. If your apartment
    building has the usual array of smartmeters, see if the noise is also
    coming from one particular smartmeter. You may need to REDUCE the
    sensitivity of the AM radio by partially covering it with aluminum
    foil.

    Some questions and comments:

    1. Is the noise present all the time or does it go on and off? If it
    does one and off, try to correlate the timing with something in the
    area the goes on and off at the same rate.

    2. Does the noise appear (in the bathroom) at every frequency on your
    radio? If you have an HF/SW radio, try different bands. If you have
    a directional BCB antenna, such as a loop or ferrite rod antenna, you
    might be able to find the source by direction finding.

    3. If you have an oscilloscope, or a laptop with a sound card running
    a software oscilloscope, try to get a screen print of the AM noise.
    This will tell me something about what might be producing the noise.
    Extra credit if you an SDR dongle and can produce a spectrum analyzer
    output. If this is too much work (which it probably is), make an
    audio recording of what you're hearing on the AM receiver and post the
    MP3 file somewhere so we can analyze it. Try to make the recording
    listening to a normally blank spot on the AM dial so that you're
    hearing only the noise and not an AM station mixed with the noise.

    4. Jumping ahead, if the noise is there 24x7 and never goes away,
    then you're dealing with some kind of noisy device built into the
    local infrastructure. Such a source is going to be difficult to find
    and even more difficult to get the city to fix.

    5. If the noise goes away at night, my guess(tm) is you're hearing
    noise produced by a PV (photovoltaic) solar inverter. Most vendors
    have EMI/RFI reduction kits available. If you have solar panels on
    your roof or nearby, it might be a possible source. Something like
    these. Make sure there's plenty of attenuation at BCB (broadcast
    band) frequencies:
    <https://www.schaffner.com/product/emc-emi-products>

    6. Check if your favored AM station is streaming on the internet or
    does simulcast on an FM frequency. The interference might be less and
    the filters more effective at 100MHz.

    Good luck.
    --
    Jeff Liebermann jeffl@cruzio.com
    PO Box 272 http://www.LearnByDestroying.com
    Ben Lomond CA 95005-0272
    Skype: JeffLiebermann AE6KS 831-336-2558

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Hobbs@21:1/5 to Chris K-Man on Wed Jul 20 18:45:16 2022
    Chris K-Man wrote:
    On Tuesday, July 19, 2022 at 5:28:18 PM UTC-4, Phil Hobbs wrote:
    Chris K-Man wrote:
    On Tuesday, July 19, 2022 at 4:08:33 PM UTC-4, Phil Hobbs wrote:
    Chris K-Man wrote:
    Hi!

    I just moved to an apartment and wanted to keep my radio in the bathroom, same as I did in the last place I lived.

    Only problem with this place is that the main electrical drop to the building is right outside my bathroom wall, interfering with FM/AM reception.

    Is there anything I can do to alleviate this - putting a noise filter on the radio power cord, etc??

    Right at the frequency of an AM I've been listening to for years, is a loud combination buzz/screeching sound.

    Maybe a variable-frequency drive for an induction motor in some HVAC
    blower. Those things are super bad news. Or it might just be a whole
    building full of SMPSes.

    It happens only to radios brought into this bathroom. Lots of static on FM, intermittent
    multiplex(stereo for the young uns!) and loud static and that buzzy-shriek right below
    80 on the standard dial(AM).

    Once the boombox is moved somewhere else in the apt, it performs like a normal set.

    This is (an example of) what I can see in the upper LH corner of my bathroom window:

    https://i.pinimg.com/originals/2e/3c/ce/2e3cceb1c024f799276a55ab05b44240.png

    A big honkin one, twice the size of a residential service! And the closer a radio set gets
    to that thing, the worse it buzzes

    Well, there's more loop area there to spray magnetic fields around than
    there is in the cables in the wall. The nasty high-frequency currents
    are probably coming from VFDs, switching supplies, and so on.

    I build a lot of sensitive front end amps in instruments, so I feel your
    pain. You still hear people advocating for star grounds, split ground
    planes, and so on. Those were great in 1950, but in 2022 there's so
    much RF and miscellaneous hash running round that a split ground plane
    is as good as an antenna.(*)

    (*) There are fairly popular antenna designs based on slots and patches
    in planar conductors.
    ______________

    The point is, it's an issue, especially at certain parts of the AM dial, when a radio
    is within 10 feet of the service mast outside my bathroom corner window. Outside
    of the bathroom corner of the apt, the interference drops off exponentially.

    "Doctor, doctor! It hurts when I go like this!"

    "So don't go like that." ;)

    Cheers

    Phil Hobbs

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From legg@21:1/5 to thekmanrocks@gmail.com on Thu Jul 21 15:09:29 2022
    On Tue, 19 Jul 2022 14:00:58 -0700 (PDT), Chris K-Man
    <thekmanrocks@gmail.com> wrote:

    On Tuesday, July 19, 2022 at 4:08:33 PM UTC-4, Phil Hobbs wrote:
    Chris K-Man wrote:
    Hi!

    I just moved to an apartment and wanted to keep my radio in the bathroom, same as I did in the last place I lived.

    Only problem with this place is that the main electrical drop to the building is right outside my bathroom wall, interfering with FM/AM reception.

    Is there anything I can do to alleviate this - putting a noise filter on the radio power cord, etc??

    Right at the frequency of an AM I've been listening to for years, is a loud combination buzz/screeching sound.

    Maybe a variable-frequency drive for an induction motor in some HVAC
    blower. Those things are super bad news. Or it might just be a whole
    building full of SMPSes.

    Cheers

    Phil Hobbs

    --
    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
    _______

    It happens only to radios brought into this bathroom. Lots of static on FM, intermittent
    multiplex(stereo for the young uns!) and loud static and that buzzy-shriek right below
    80 on the standard dial(AM).

    Once the boombox is moved somewhere else in the apt, it performs like a normal set.

    This is (an example of) what I can see in the upper LH corner of my bathroom window:

    https://i.pinimg.com/originals/2e/3c/ce/2e3cceb1c024f799276a55ab05b44240.png

    A big honkin one, twice the size of a residential service! And the closer a radio set gets
    to that thing, the worse it buzzes

    You should check the ground connection of the power conduit, where it
    meets the service entrance.

    Your boom box possibly has a screw connection marked 'antenna' for
    a straight wire, or a telescoping antenna - both are usefull for FM
    directional preferential reception. You may have to engage a switch
    somewhere to select either.

    You can forget about AM. In the region of any concentration of
    commercial, residential or tranport activity, reception will be
    noisy at best.

    RL

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  • From whit3rd@21:1/5 to Chris K-Man on Fri Jul 22 00:38:08 2022
    On Tuesday, July 19, 2022 at 12:58:55 PM UTC-7, Chris K-Man wrote:
    Hi!

    I just moved to an apartment and wanted to keep my radio in the bathroom, same as I did in the last place I lived.

    Only problem with this place is that the main electrical drop to the building is right outside my bathroom wall, interfering with FM/AM reception.

    It's possible that the bathroom has a big mirror (which is a conductor, so shields/reflects RF) and that's part of why
    reception is poor. Move the radio to different spots, and if you find a place that DOES have
    reception, consider mounting a shelf there...

    A fluorescent ballast can be a major noisemaker; have you tried switching things off in the vicinity?

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  • From ohger1s@gmail.com@21:1/5 to Chris K-Man on Fri Jul 22 10:03:38 2022
    On Tuesday, July 19, 2022 at 3:58:55 PM UTC-4, Chris K-Man wrote:
    Hi!

    I just moved to an apartment and wanted to keep my radio in the bathroom, same as I did in the last place I lived.

    Only problem with this place is that the main electrical drop to the building is right outside my bathroom wall, interfering with FM/AM reception.

    Is there anything I can do to alleviate this - putting a noise filter on the radio power cord, etc??

    Right at the frequency of an AM I've been listening to for years, is a loud combination buzz/screeching sound.

    Most AM noise I've found is worse between 700KHZ - 1MHZ. At my house, the AM is almost unlistenable, and I'm in the middle of a 5 acre lot. What I found by shutting off all breakers and turning them on one by one was several items contributing to the
    din. I found my outdoor motion sensing light fixtures were causing noise (took them apart and hard wired them then added Honeywell wall dusk to dawn switches), my alarm system (added low value capacitors across all keyboard lines at the panel), but the
    biggest offender was my wifi router. I took it apart and found the PFC cap bulged and changed it. It cut the noise down but it still generates a racket.

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