[TowerTalk] Power Line Interference

[John T. Nogatch]

In Mar-96 I got back on HF for the first time in many years.
Over the next few months it became obvious that my noise level
was much higher than it was for other hams in my area. I had also
noticed that there was strong noise on the AM broadcast radio
as I got close to home, and it had been this way for 9 years.

I watched the pole transformer in front of my house very closely,
often checking on dark quiet nights for any sight or sound of
arcing; I never observed any. The noise was very bad on 40m,
not a problem on 30m, and bad on 20m (fone difficult, but
CW with 500hz filter OK). Sometimes it seemed heavy rain would
change the noise, but other times not.

17-Oct-96 I reported the situation to Pacific Gas & Electric.

26-Jan-97 the power was out due to a windy winter storm.
I don't usually operate during the Superbowl, but since the
power was out, and my rig runs on a storage battery, I went
ahead and thought I worked VK0IR. However, I never did show
up in the online log.

20-Mar-97 I re-reported the situation to Pacific Gas & Electric.
They still had my previous complaint on file, and said, "They'll
get to you by summer."

2-Apr-97 Another wind caused power outage revealed that the
high noise level was power line related. I was about to answer
an HL0 on 40m CW when the power came back on, and the noise level
climbed from S2 to S9. Turning off the main breaker to my house
did not affect the noise level.

17-Apr-97 PG&E left a message on my home answering machine asking,
"This report's kinda old. Are you still getting interference?"
He gave me a phone number to call.

18-Apr-97 I left a message describing the continuing noise and
asked that they call me at my office number to discuss it.

25-Apr-97 I left an additional message because they had not called.

30-Apr-97 He called me at my office and said, "The transformer
in front of your house has a broken skirt. Repair crew should
fix it within the next day or 2."

29-May-97 I left a message asking if anything had been done,
because I have seen no change at all.

28-Jun-97 While packing the car for Field Day, PG&E arrives with
a big snorkel truck and replaces the pole transformer. The noise
was greatly reduced. The crew was all smiles and said, "Sometimes
we change it out, and the noise is still there." I asked them
whether these old transformers contain PCBs and the smiles
disappeared. They said there may still be a few in service, but
they almost all have been replaced by transformers filled with
mineral oil. I noticed that the new transformer has large
insulators on top in parallel with some things that look like
large power resistors (wirewound on ceramic forms).

30-Jun-97 I left a "thank you" message.

I have since worked several DX stations on 40m CW, including
South Africa, which would have been way below the noise before.

Lessons learned:
   1. Interference can be tricky to isolate.

   2. Running off battery power is very useful.

   3. Much patience is needed when dealing with the power company.

   4. 40m is a great DX band, but
      "If you can't hear 'em, you can't work 'em."


+------------------------------+
| John AC6SL   jtn@te-cats.com |
+------------------------------+

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