"DougSlug" wrote in message
...

----- Original Message -----
From: "DougSlug"
Newsgroups: rec.radio.scanner,alt.radio.scanner,alt.ham-radio.hf
Sent: Saturday, March 10, 2007 7:08 PM
Subject: Carrier tones every 15 kHz in 10m band


What about harmonics from wireless routers? Could that explain this
interference pattern? - Doug

It seems very unlikely to me. That stuff is up in the GHz.
They don't tend to make subharmonics.

The carrier frequency is around 2.4 GHz, sure, but the data bursts are
quite a bit slower. What I don't know about is whether wireless routers
broadcast data bursts at regular intervals that somehow may be getting
demodulated in my receiver.

They don't transmit at regular intervals.
They transmit only when there is
data to transfer.



It is the wireless router, a NetGear WGR614. I don't know why the hell I
didn't try that earlier. It does the exact same thing to my Icom IC-R20.
Maybe the power supply in the router? Or is it a wireless signal
phenomenon? - Doug

Congrats on finding the problem.

I've got a NetGear WGR614. It worked for
a year then developed a heat problem. It will
only run for about an hour. I openned it up.
(Pry open the rubber feet and there are four
little torx screws.)
The Broadcom chip gets hot enough to burn
your finger. Other people have reported the
same thing. I bought a Linksys a few weeks
ago to replace it.

And I see the little transformer for the switcher
in the NetGear. There is virtually no doubt that the
problem is the switcher and not the wireless part.
1. The wireless is bursty and not regular. (Certainly
not 15 kHz regular.)
2. Problems are almost always with harmonics and almost
never with subharmonics. (How are you with Fourier
transforms and convolution?)
3. TV broadcasts would be giving you fits too
if your radio were sensitive to 15 kHz components
of VHF/UHF signals.
4. Probably no other 802.11 device you have
causes the same problem.

There is a way you can test it. On the router's
control page there is an option to turn off its radio
while still being able to use the router with
wired connections. You might try that.

Another thing. It is almost always long wires that
do the actual radiating. The switcher can generate noise but it
won't go anywhere unless it gets coupled into the
cables that attach to the router. Try unplugging
the eithernet cables too to see if the noise goes away.
That will leave the power cable. You could then try
putting ferrites on the power cable, or wrap it up in a
tight ball to keep it short.


cheers,
rb