On 23 Mar 2014 at 13:45, Ed K0iL wrote:
> Ken,
>
> Based on your latest description, are you looking for narrow-banded noise
> spikes?
No.
> Or is it really very broad-banded--only being stronger at the resonant
> frequencies of the antenna you're using?
Yes. Exactly, in fact.
> Power line noise is always very broad-banded getting weaker as you tune
> higher in frequency
That is exactly what I am experiencing here
>--this is more obvious when using a broad-banded
> log-periodic antenna like I have at work. Whereas the really strong,
> narrow-banded, spiked noises are usually generated by various in-home
> devices like TV sets and computers.
I have eliminated those from consideration: I connected the FT-890 to a
battery, and killed the house main breaker which turns off EVERYTHING in
the house.
There was absolutely no change whatever in the noise. None. Zero. Nada.
Conclusion: it ain't in my home. :-)
> Also keep in mind when tracking power line noises, you will find RFI sources
> everywhere,
Boy! Ain't that the truth!
> but not all of them, and probably only a few of them will cause RFI
> noise to your ham antenna because of standing waves (peaks and nulls) along
> the
> power lines. The best way to determine if the noise you tracked down is the
> same noise you are hearing at your ham shack is to get a visual waveform
> reading
> on a scope.
Although I do have a portable 20 MHz dual-trace scope, I don't have it in the
shack at the moment. It is in storage. I am hoping I won't have to dig it out.
In
the meantime, I am using Spectran and a laptop.
> This waveforms method is recommended by Mike Martin, K3RFI, of RFI
> Services, and is described in the book "AC Power Interference Handbook" by
> Marv
> Loftness, KB7KK. I'll attach a QST article that describes this method.
Thank you. I'll read it immediately.
> Your power company should be using this waveforms method to track power line
> noise and reduce the amount of RFI repairs they need to make to meet the FCC's
> Part 15 requirements. Why fix noises that do not cause RFI to any licensed
> services? (or at least have not generated and complaints!) This makes both
> the
> power company and the ham happy.
Yes. I am in contact with a power company employee who also happens to
be a ham, and is also in charge ot taking care of RFI complaints. If things go
well, I may see him next week.
> Good hunting and GL!
Thank you, Ed.
vy 73,
Ken W7EKB
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