Hmmm ...
> also very loud at 78.5kHz and at all multiples of 78.5kHz right
> up into the AM broadcast band.
We can work with this.
Any ham who is tying to track down 'noise' should have
at his disposal a battery-operated AM radio for the utility
of its highly directional ferrite 'loopstick' antenna.
While not a panacea, and you might have to 'watch out'
for coupling to fields as opposed to a 'propagated' signal
at AM broadcast frequencies, but stronger in these cases
still means 'closer to the source'.
I have hiked around in the past checking 'pole' noise by
holding the AM receiver in vicinity of the ground wire
running down the pole, but I digress ... if this signal is
receivable on the AM broadcast band I suggest a little
recon using the AM receiver in the car!
I have also had success using a consumer-class
transistorized portable battery-op AM/SW receiver
that utilized a ferrite rod antenna up through 6 MHz; this
has worked well DFing 80 Meter noise sources, one of
which was 3/4 mile or so distant (a power pole power-
factor correction cap bank complete with timer-controlled
switch on a 3-phase 14 KV line)!. Another ham had gone
out using a 2M rig and a beam and never found it; I
noticed that the amount of energy from this source was
considerably less in the 100 MHz and up bands
compared to that in the SW spectrum.
And FWIW - my hall light, w/an incandescent wired up
to a remote control BSR X10 light dimmer module is
only noisy with the light on and is quiet with the light off.
Jim P // WB5WPA //
----- Original Message -----
From: "Jim Idelson" <k1ir@designet.com>
To: "RFI Reflector" <rfi@contesting.com>
Cc: "CQ-Contest Post" <cq-contest@contesting.com>
Sent: Thursday, February 14, 2008 5:13 PM
Subject: [RFI] RFI Frustration
> Well, it's the night before the contest and the noise is still there.
>
> It's a 24/7 noise and I can DF it in one direction with yagis on 40-10
meters. It's pretty broadband and it has a sputtering sound, somewhat like
this light dimmer noise -
http://www.arrl.org/tis/info/HTML/rfi-noise/noise/noise-files/lightdimmer.mp
3
>
> found at
> http://www.arrl.org/tis/info/HTML/rfi-noise/appliances.html
>
> Is a noisy light dimmer going to be a constant source or does it change
with load and when turned off?
> I had been listening for this at high frequencies, but when I saw that
this is something that has a baseband frequency in the 150kHZ range, I tuned
my big rig in the station down there on a 160m dipole, and there is a very
loud noise at 157kHz. It is also very loud at 78.5kHz and at all multiples
of 78.5kHz right up into the AM broadcast band.
>
>
> Suggestions for better DF'ing techniques? I've been outside around the
neighborhood with my HT, sniffing power meters, wires coming down he power
poles, etc. There are some hot spots, but nothing like a smoking gun.
>
> I have a little time tomorrow to sniff around the neighborhood some more
to see what I can find. I've been in the two closest house with the HT, but
found nothing.
>
> Wouldn't it be cool to find and eliminate this just in tme for the
contest?
>
> 73,
>
> Jim Idelson K1IR
> email k1ir at designet.com
> web http://www.k1ir.com
>
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