Jim -
Is this noise on 160M only, or all ham bands? Is 160M the worst, but all
bands afflicted?
You said your noise blanker works well on the noise, which is one clue.
Another thing you can do: Turn off the noise blanker, go to the part of the
band that has the worst noise, and set your rig for AM reception on the
widest bandwidth you have. Put the resulting audio on a scope or feed into
a computer and make a scope trace using audacity. Zoom in and see if the
noise really is 120Hz spikes. If it is 120Hz spikes, then it is utility
related (not necessarily the utility's hardware, could also be customer
side stuff). If instead you have whiny noises all over 160M, then it is
likely from a switching power supply somewhere in your area or a dog fence,
and not going to be resolved directly by the utility.
If you have 120Hz spikes audible on AM afflicting 160M, then you can just
drive around with your car's AM radio near the top of the AM band and get
some idea of the affected area. When you get close you to an offending pole
you may find that higher frequencies are also afflicted, and may even
affect FM reception. If you have a HT that has AM mode, it will go nuts
when you are right under the bad pole.
I have been afflicted with 120Hz utility impulse noise many times, and
every time the local utility has been able to track down (not so fast) and
then repair the offending pole (surprisingly fast.) Different bands have
been afflicted each time. In several of the worst cases after finding the
offending poleIu can hear the buzz of something arcing overhead with my
ears when standing near the pole.
Tim N3QE
On Sun, Oct 25, 2015 at 6:13 PM, Jim Murray via Topband <
topband@contesting.com> wrote:
> Greetings,Last Fall we moved into a new location. This Summer I spent a
> lot of time and effort putting up an Inverted L and radial system. Now
> after tuning, etc. completed I have what appears to be power line noise,
> source unknown at this time. I threw the main in our home and noise still
> remained. The closer I get to the power lines or the antenna system the
> louder it gets. As I jump in freq., the higher the band the less noise. I
> have a portable receiver that is capable of rx on the ham bands. As it
> sits right now 160 is just about out of the question. Rig is a ft1000mp
> mk5 field and the NB does do a good on the noise but also on the weak
> signals. This is the first location in 35 years that I've run into this.
> I don't have much faith at this point in the power company finding the
> source but will call them this week. Any ideas would be greatly
> appreciated and also wondering about Noise Phasing with MFJ-1025. I read
> w8ji article on it but not sure if it would help on noise of this
> magnitude.Regards,jim/k2hn
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