I have a very severe interference problem here at my QTH
that has been present for more than a year now. It sounds
to me like "power line noise" and the local electric utility -
ComEd - has been out to my QTH numerous times and has
told me that all of their lines are "within spec;" they cannot
find any problems anywhere close to my house.
The interference is present on ALL HF bands, from 10
thru 160 meters, including all WARC bands. The noise
starts out at somewhere between S6 - S7 on 10 meters
and as the frequency goes down, the noise level goes up,
to S9 on 80 meters and S9 + 10 dB on 160 meters.
The noise is always present. It doesn't matter what the
weather is, whether windy, rainy, snowing or clear. I
have done a little investigating and found out a few things.
The first thing that I did was to turn off every circuit breaker
in my house, except for the one that feeds my radio equip-
ment. With all the other breakers turned off, the noise is
still present, just as loud as always. My rig is not capable
of being operated on 12 VDC so I have to leave the one
circuit breaker on that powers the rig.
The next thing that I found out is that if I rotate any of my
yagis to the direction where the wires cross the road from
my property to the other side of the road, the noise level
peaks when the antennas are pointed at this direction. When
the antennas are pointed away from this location, the noise
level drops to its lowest value.
The third thing I did was to take a battery-powered AM
radio and walked out to the pole in my yard where the
wires cross the road. When I approach the pole in my yard,
the noise level that the radio is picking up begins to get much
louder. When the radio is placed next to the pole, it gets
even louder still.
I then took the radio and walked across the road, under the
wires. The noise was still present but not as loud. When I
placed the radio next to the pole on the other side of the
road, the noise increased to about the same level as it was
when placed next to the pole in my yard.
The pole that is across the road from my property (had) two
guy wires that were used to help support the pole. One of
them had a strain insulator in it and the other didn't. I found
that when I placed the radio next to the guy wire that didn't
have an insulator in it, the noise got to its loudest level ever.
I then placed the radio next to the guy wire that had an
insulator in it and was still able to pick up the noise but it
wasn't nearly as loud as it was when the radio was placed
next to the guy wire that had no insulator in it.
One day after making this "test" with my portable radio, one
of the line crew guys from the utility was in my area, trying
to find the noise. I told him about my findings. He advised
me that the guy wire that didn't have the insulator installed
in it belonged to the cable TV utility, as it was being used
to support their coax cable and that I'd need to check with
them and get them to come out & see if any of their lines
were causing the interference because he could not find any
problems with the power lines.
I then called the cable TV utility and asked them if they
could send a tech out to my area, after informing them
about the interference to my ham radio station. I was told
that they would send a tech out to do a "sweep" of the
area and let me know if they found any problems. A few
days went by and I never heard a thing from them so I
called them back and spoke with someone in their Tech-
I was told that a tech did indeed come out to my area but
was only able to find a very small amount of leakage; it
taking place a couple of miles from my house and that it
was caused by a loose connector which they told me had
got tightened up and in doing so, took care of the problem.
Well, I still had the interference as bad as ever and have
called them back, to see if someone could come out and
check their power supplies that are mounted on poles that
are located on the road adjacent to my house. So I am
now waiting for someone to come out and check these.
I guess what puzzles me most is the fact that when we had
the house built in 1984 and moved into it in 1985, this
area was extremely quiet, insofar as power line noise is
concerned. Once in a while, in years past, a line noise pro-
blem would present itself and someone from ComEd's
Line Crew would come out (usually relatively quickly), find
the problem, make the repair and that would be the end of
At first, ComEd was extremely helpful when it came to
line noise problems. The Line Crew guys were glad to take
care of the problem so that it didn't become a larger pro-
blem. Also, I got to be on a "first name basis" with the
foreman of the Line Crew, who gave me his direct telephone
number and he encouraged me to call whenever a line noise
problem would present itself.
The past few years though, ComEd has cut way back on
the number of personnel on their Line Crew. Also, the Line
Crew foreman retired and one of the Line Crew guys who
used to come out here from time to time has retired, also.
To sum up my situation, I have had this problem for well
over a year now. The last time that ComEd's Power Qual-
ity Engineer came out here, he informed me that ALL of
their lines were "within spec" and that the noise that I am
picking up must be due to some customer's "connected
load." I asked him if he had any idea which customer's
"connected load" might be causing the problem and he told
me that he didn't know!
I used to tune the bands (the CW sub-bands), looking for
DX to work but this noise problem has pretty much taken
care of my desire for doing that. Low-band DX'ing is
pretty much a thing of the past for me, unless the DX sta-
tion has a pretty loud signal.
I guess when it warms up a little, I'll try to find someone
who has either a 2 meter rig with AM capability or a re-
ceiver that can receive the AM aeronautical band and
try to use a 2-element yagi to try to pinpoint the location
of the noise. I don't know what else to do. If anyone has
any tips or suggestions, feel free to pass them along to me.
Thanks in advance!
73 de Brad, N9EN