Noise noise noise, radio noise, interference that is. My house is haunted
by some kind of interference. I can't tell if it is 60 or 120 Hertz. I
tried to find a simple online (preferably Active X) sound analyzer or
oscilloscope to measure the noise, using the audio output from the Icom
R-75 to the sound card, but no luck finding a suitable program yet.

One of the sources of noise is my Son's cellphone charger, probably a
cheap switching type, it weighs nothing at all. Anyway, this throws out
interference from about 2.5 MHz to at least 12 MHz, very strong. Unplug
it, viola, the noise level drops. Yet not enough. Another takes it place,
at least in the 3.2 MHz and below, no doubt even in much higher ranges.
In an attempt to locate this rascal I selectively unplugged what I
considered likely offenders. No luck. Then I turned off all the household
power, except the circuit for the receiver, and the sound continued
unabated. I tried substitution for the transformer for the affected
radio, no difference. I awoke this morning and noticed that the noise
level was way down. Good, yet later in the day it was back. Usually it
can still be heard just as loud at midnight as it can be hear at noon.
Why the attenuation this morning is beyond me.

I have an Icom R-75 and a Yaesu FRG-100, in different rooms, with
different antennas, they are both similarly affected by the noise. One is
in the front of the house, the other the rear. Just yesterday, I
installed an outdoor antenna on the Yaesu, a yet ungrounded antenna,
stretching within 45 feet of the house. My Yaesu was the recipient of a
lightning strike that came down the tree in the rear of the yard, jumped
to the antenna wire essentially fastened to the tree, and was mostly
shunted to ground. The balance came in through the radio and did
extensive damage to some electronics in the house, yet the Yaesu survived
with a simple obliterated circuit board track.

The Icom has an indoor antenna, a simple wire that goes around the
ceiling, tucked into the ceiling/wall junction, offering around 30 feet
of wire.

The Yaesu has this antenna, coax fed,
http://www.universal-radio.com/catalog/sw_ant/2205.html 45 feet in length
for the antenna wire itself, traveling from the window to a nearby fence
post, on the opposite side of the house from the Icom receiver. The Yaesu
also has an indoor antenna, similar to that used by the Icom, except that
the room is larger therefore the indoor antenna is longer. Regardless of
the antenna, the interference is always there on either set. The
interference is also to be heard on my Sony 7600GR when battery operated.

So where does the interference come from? Neighbor? Radio signal versus
power line? Since the radio maintains an S9 noise level almost
continuously on many frequencies, how is one to listen to distant
stations?

What's my next step? I have found 2 offenders, my Son's cellphone charger
and the stupid Hughes Direct TV Receiver, sheesh, it's SO BAD it kills
the cordless phone (900 MHz digital) if you get too near it. This
afternoon, while in the backyard with the Sony, and the Direct TV
Receiver being in the front of the house, I noticed that 9115 KHz was
obliterated with noise. I went into the house, unplugged the Direct TV
receiver, and viola, the noise went away. Yet even with these unplugged,
far too much of similar noise is to be heard. I have whole house surge
protection, mounted at the electric meter, can this be a source?

Any suggestions on an effective way to track and reduce this type of
interference? If it is in the power system, what can be utilized to block
the interference, or at least attenuate it? Since I can hear it on the
battery powered Sony, most likely it is radio interference, but my house
is likely NOT the origin of the noise, where do I go next?

Thanks,


Dr. Artaud