I had a similar situation several years ago. My situation included the CATV
shield
radiation issue as well. Turned out to be a neighbors PC was causing the
problem.
The PC had no AC line filtering and the switching supply garbage was using the
AC power
line and grounds of the CATV as antennas.
A W3NQN AC line filter at the computer fixed the problem.
I would check your own PCs first and then those of your neighbors if possible.
I had
the power company RFI guy with me when we went to the neighbors house and that
helped
me gain entrance and allowed the install of the filter as well.
73,
Tim K3LR
W1gfh@aol.com wrote:
> Gentlemen,
>
> After a year of living with it, and a few weeks (all too brief) respite, my
> neighborhood RFI FROM HELL is back.
>
> This RFI is S9 +40db. It is "on" 24/7. It has "spurs" every 10 or 20 kHz on
> 75 meters, widening to every few Mhz aboove that. The harmonics gradually
> weaken and disappear above 30 mhz. I can't find any on VHF, even with a very
> sensitive receiver.
>
> (I am pretty sure it is not an arcing pwr line insulator. Listen to the
> quicktime movie file [below]. It's too steady and rythmic)
>
> A few months ago, the local cable TV company came by and measured with a
> leakage detector (UHF) and found nothing unusual. They replaced my cable drop
> anyway. The local power company gave their system a clean bill of heath. I
> still
> had the RFI.
>
> What bugs me most is that it oscillates/wavers across 30 or 40 kc. It also
> more slowly moves up or down the band according to temperature/time of day, so
> there is no possibility of phasing it out.
>
> The outdoor TV cable drop radiates this signal VERY strongly. By using a
> portable SW receiver and touching the antenna to shield of the TV cable, I
> can get
> spurs up to 60 mHz. But nothing above that.
>
> It also appears to radiate from cold water pipes, as well as house wiring.
>
> To review:
>
> -RFI is 24/7, fundamental frequency on 3-4 Mhz.
> -Only abated (temporarily) by HEAVY RAIN
> -Cable TV company disavows any culpability.
> -Utility Co. disavows any culpability.
> -Did a "full power down" on my dwelling. No change.
>
> Any insights are appreciated.
>
> Sincerely,
> Joe, W1GFH/6
>
> *Why do I call it "RFI from Hell?". Take a listen. Here's a brief
> quicktime/Mpeg/AVI showing the noise pattern on my Icom 756 spectral display.
> Truly
> horrifying.
>
> http://www.members.aol.com/jtyburczy/DSCF0001.MOV
>
> Also see thread at:
>
> http://amfone.net/phpBB2/viewtopic.php?t=1231&postdays=0&postorder=asc&start=0
>
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> http://lists.contesting.com/mailman/listinfo/rfi
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