[ARC5] RFI noise sources

[Larry Osborne]

I have a similar, but worse, problem. I retired several years ago and I
finally got my ham license. I have played with HF since I was 12 (although
I stopped transmitting illegally when I was 16 or so), and looked forward
to finally being legal. One night I was aligning a Heathkit Mohican when
suddenly the whole shebang was overrun with noise. I figured I had done
something stupid and went to bed figuring I'd see what I had done wrong the
next day.

But the noise was still there. My Kenwood had always shown noise at about
the S3 or 4 level, which was bad but still usable. Now the noise pinned the
needle. Same thing on my vintage sets and my Sangean portable. When we had
the big ice storm and the power was off the noise went back down to S3.

There doesn't seem to be a source of the noise; I've tried to locate it. No
luck; there's no null anywhere. It happened all of a sudden. It's power
related (but that might mean it's caused by something *being* powered). I
tried turning off the master circuit breaker for the house, hoping I had
something causing it plugged in … no dice. I've tried phasing noise
cancellers, directional antennas, magnetic antennas, all sorts of things.
Very irritating. Everything from AM broadcast to 30 mHz is useless in my
whole neighborhood.


Larry Osborne Ph.D. (Ret.)
   No longer an authority on anything
KI7UFC
+1 808.630.8176
     or via W.A.S.T.E.




On Mon, Aug 26, 2024 at 1:28 PM Tim <timsamm at gmail.com> wrote:

> Didn't want to hijack the Code Wheel  thread...However:  Interesting RFI
> paper Steve - Thanks...
>
> Just for fun I just tuned my HF receiver from 7.0 to 8.0 mc.  Located in
> Suburbia, low halfwave dipole, noise floor at quiet freqs about S2 at 1315
> Local.
> I counted 24 hashy, fairly broad noise sources in that band that showed
> above S4, there were many other weaker ones.  You can even see their
> presence on some remotely located SDR sites that were picked as to be
> "quiet".  You can watch them drift around in the waterfall tuning
> ranges...Probably local to the antenna.
>
> Since I work 40 CW fairly often I find these things drift around and
> invariably land on that weak CW op I am trying to work. They then drift
> away after a minute or so.
> Since our ((not)great) power utility power company fails pretty often
> around here I get a chance to scan the bands while the neighborhood is
> "out" using battery powered receivers - very quiet.  I did find a bad wall
> wart in my own house that way - it powered a USB gizmo.  Replaced, S9 noise
> gone from that one; gave it a new attitude with a ball peen hammer...
>
> Anyway my $ 0.02
> Thanks, Tim
> N6CC
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