Tracking Local QRN

[dalekretzer]

    I recently uncovered a surprising source of in-house r.f. interference on 40 meters, hindering reception on my beloved K2/100. I had already eliminated such sources as defective touchlamp units, and replaced wall-mounted dimmer switches that are infamous for the static they generate. That left me still contending with a wide, noisy signal about every 10kc across the entire 40 meter band, including 7045 where Kevin conducts the Sunday ECN sessions.
    I grabbed my handy KX1 and a loose coil of wire, clipping it to the antenna input and using it as a direction-finding loop. In no time at all, it led me right to the source of the signal .... our home security system! An oscillator used in the device was radiating strong harmonics throughout the house on all the wires running to the door and window sensors. Talk about a curtain antenna!
    In this case, the cure is expensive because the central monitoring unit is having to be replaced. It was not type-approved by the FCC. The new system is guaranteed not to be a spurious generator on the ham bands.
    I'd never thought of the KX1, or any of the little Elecraft rigs, as an rf interference "sniffer," but they work ideally for that purpose. A properly designed, handheld loop antenna might be required in tougher cases, but give anything handy a try and see what surprises you uncover.
    Happy hunting.
    Dale -K6PJV
    Sacramento, CA.
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[Paul Meier]

Door bell transformers can also be a problem we've found also.

Paul K7PM
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[k6dgw]

Dale Kretzer wrote:
> I'd never thought of the KX1, or any of the little Elecraft
 > rigs, as an rf interference "sniffer," but they work ideally
 > for that purpose. A properly designed, handheld loop antenna
 > might be required in tougher cases, but give anything handy
 > a try and see what surprises you uncover.

I've often used my KX1 to locate noisy electric fences in the area.
I've never bothered with a loop ... just a piece of wire in the antenna
jack.  When I get close, I use a part of a paper clip in the connector,
and if I'm within about 50-60m of the arc, it almost doesn't even take
that.  So far, it's worked every time.

I also inadvertently found some gizmo on a power pole that was radiating
narrow band noise at about 7055 while I was looking for a fence problem.
   I just happened to be listening to the fence on that freq.  I don't
know what it is, but I called the power company, and they must have
replaced the box because it is still there but the noise disappeared a
couple of days later.

KX1's have many uses :-)

Fred K6DGW
Auburn CA CM98lw

PS:  The ARRL 10m contest is on.  SFI=96, Kp=2, and X-ray flux is fairly
low and declining.  Lots of LU's, PY's, HP's, a couple of YV's, PJ2T,
and at least one HC on CW.  Sigs are pretty strong into N. Cal.  Also
worked a ZL on CW.  Not too shabby for the bottom of the cycle.
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[Mark J. Schreiner]

When nobody else is home and I want to find noise in the house (or
eliminate that the noise is coming from my house) I have my K2 connected
to a battery and I go over to the circuit breaker panel and start
flipping breakers off.  I can start with everything off if I want to be
thorough and then gradually add one at a time back on, or I can flip one
at a time off and back on.  My hamshack, luckily, is near the breaker
panel so I can instantly hear if the noise is switched on/off with the
breakers.  If I do find that a particular breaker quiets down the noise
at least I can figure out what is all on that circuit (not so easily
done in a house that was built in the '20s with various "generations" of
wire from knob-n-tube to much nicer modern wiring that was put in by
myself or the previous home owner about 8 years ago.  Oh, of course
there are various things that have battery backups such as security
systems, smoke alarms, UPS for computer (many computers aren't 100% off
unless completely disconnected from a power source), etc.

If your hamshack isn't so close to the breaker panel you could get more
resourceful and use another battery operated transmitter (hmm, maybe
that would be a good use for a baby monitor once your baby is all grown
up, assuming those things are battery operated, I think the Rx is
usually, at least) or if you have somebody else that can work the
breakers while you listen to the radio.  I have 3 different dimmer
switches and haven't noticed a problem with them (yet).  I have some
flourescent lighting in the basement, which I always considered to be a
no-no, but it doesn't seem to raise my noise floor more than other
neighborhood noises.  I was a bit worried about some of those new
efficient outdoor security floodlights but I've got several installed
around the house and up at the garage and all seems okay with them as
well.  The most noise I had and eliminated quite easily was my computer
monitor which was replaced about 1 year ago with an LCD monitor, WOW,
big difference!

Using a portable radio like a KX1, K1, K2, mobile rig, SW broadcast
radio, etc. to go walking around the neighborhood might get you noticed,
unless you do it at night (especially if it is near new moon, oh, unless
your neighborhood is well lit like most modern neighborhoods tend to
be).  You may be able to identify noise that is coming from particular
utility poles and then be able to attempt to contact the utility company
to have them check it out (keep a log of when you hear the noise, what
frequency, weather conditions when you hear it and don't hear it, etc)
if you are nice enough to give them the pole number or some other
identification of location of the pole to help make their job easier.  
Our local power company just sent out with the monthly bill a notice of
an IR camera that they have to help find problem areas, a great tool to
really zero in on the cause and location of the noise after you get them
into the general vicinity.

73,

Mark, NK8Q



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