Hi Mike,
See comments below.
On Mon,10/10/2016 9:00 AM, Mike Wetzel wrote:
I have been experiencing a noise on 160 and 80 for the past couple of months
that peaks N/NE from my qth. It has peaks every 32.5/65 KHz across 80
meters. I have subdivisions with underground cabling on 2 sides of my
property (N and NE). Last week, W5LO (who lives in the subdivision to my
north and also hears the noise) and I took a drive in my car with my K3 and
we seemed to find the noise peaking in or around a specific house in his
subdivision. We contacted the owner who did cut the power to the house and
the noise did not stop.
How far are you driving from your QTH? When set up for a CQP county
expedition last weekend, we had electronic noise on 20M. The closest
possible source had to have been at least a mile away. W8JI has reported
hearing sources at 2-3 miles.
Also -- when cutting power to a house (or to a specific circuit), a UPS
may be keeping computers and associated equipment running. AND -- a UPS
has a DC power supply that keeps the battery charged, probably an SMPS,
and the power it generates when it loses power will be full of RF
harmonics.
A friend of mine, W9KY and I, used his Sony SW receiver and loop antenna to
try and pin point the noise on Saturday. We heard the noise on his radio
with a whip antenna at my house and took off walking the subdivision.
Listening on the loop on 3820 we heard the noise but were not able to pin
down it's location. The subdivision does have AT&T U-verse, Comcast and
many have small DirecTV or DISH satellite dishes/receivers on/in their
houses. W5LO has DirecTV and we noticed that we heard the noise around his
splitter coax cables coming from his dish and distributed through his house.
But even disconnecting power from his unit did not stop the noise. It is as
if the noise is being radiated from some device (most certainly nearby) and
is then being picked up by his coaxes.
Yes, possibly coupled as a common mode signal onto his coaxes by another
piece of equipment that is generating it.
In W5LO's attic, we could barely
receive the noise on W9KY's receiver, but when the loop antenna was put next
to the coax cables, the noise increased significantly again all power off.
Loop antennas couple to other antennas (in this case, the coax). While
chasing 160M noise at my QTH several years ago with a talkie tuned to
160M, I copied N7DD loud and clear when I held the base of the talkie
next to the ground wire on a wooden power pole.
I am at a loss as to how to proceed and pinpoint this noise source. Anyone
with any ideas?
Study the P3 display to learn whether the noise is a "hump of noise"
that drifts slowly or fast (typical of a SMPS or variable-speed drive
motor controller) or a distinct carrier that is stable in frequency
(typical of some sort of digital equipment). This can yield a clue as
to what product might be generating the noise.
73, Jim K9YC
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