"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

Actually, it is on a battery--always was. - D

"mikeFNB" wrote in message
...
weird!!!!!

psu then or xlal osc inside for baud rate etc.
try it on a battery

mike

"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.


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

Folks, be awared of that flatscreens (PLASMA) is a highly annoying
"jammer" noicetransmitter on the whole HF-band.
As that is NOT for the LCD.



mikeFNB wrote:
wireless router what at 2.4ghz!!

try killing the power to your house while running the RX'er from a battery
or car.
that should give you agood idea if its you or not

mike

"DougSlug" wrote in message
...

"Ron Baker, Pluralitas!" wrote in message
...

"Edmund H. Ramm" wrote in message
...

In "Ron Baker,
Pluralitas!"
writes:



"DougSlug" wrote in message
...

While tuning through the 28.3 to 28.5 MHz portion of the 10m band in
USB
mode, I get what sound like carrier tones very evenly spaced every 15
kHz
starting at about 28.3 MHz.

I am using an AOR AR8600MkII receiver with an AOR SA7000 antenna
mounted
on a mast outside. I am located in central NJ in the
Princeton/Trenton
area.

What is the source of these tones?

Thanks,
Doug

The horizontal sweep of television sets is 15750 Hz.
Switch mode power supplies operate anywhere from
10 kHz to 100 kHz.
It is not uncommon for either of them to ring and generate
harmonics in HF.

In the case of switch mode power supplies the spikes IMO would be
120Hz apart (100Hz where I live). And most of the rf energy is spilled
from abt. 1 to 7 MHz, with almost nothing left to be found on 28MHz.

73, Eddi ._._.
--
e-mail: dk3uz AT darc DOT de | AMPRNET:
If replying to a Usenet article, please use above e-mail address.
Linux/m68k, the best U**x ever to hit an Atari!

The mains frequency has little to do with the noise
that a switcher can generate. A switcher rectifies and filters
the mains to DC then uses a switching transistor to
drive a transformer at a much higher frequency. Tens of
kHz typically. The higher frequency allows the "magnetics",
i.e. the tranformer, to be much smaller physically than
a 60 (50) Hz transformer. That plus the on-off and not
linear nature of the switch allows switching power supplies
to be smaller and more efficient than linear supplies.
It is the switching, with sharp edges, that generates
high frequency components. I've seen poorly designed
switchers generate harmonics into the hundreds of MHz.


--
rb

I understand about the noise and harmonics a switcher can generate, but
the thing is that my antenna is mounted outside on a mast 25 feet up. All
the wiring in my neighborhood is underground. It's not clear to me how I
could be getting such strong interference in this case. What about
harmonics from wireless routers? Could that explain this interference
pattern? - Doug

Someone in my neighbourhood got a new toy for Christmas, and when they play
with it I get a noise repeating precisely every 200 kHz from about 4 MHz
though to 30 MHz - some places worse than others - i.e. around 8 and 15 MHz
they exceed S9. I have sent audio and spectrum recordings to a specialist in
RFI, who was able to determine that it is a switcing power supply, but just
which one and for what is still unknown.

All wiring in my subdivision, including telephone and cable TV is
underground. Other than satellite TV antennas the only visible antennas or
feedlines within at least half a mile are mine. When spring comes I'll try
to localise it with a portable receiver. It is definitely none of my
immediate, within 200 feet, neighbours. I suspect a plasma TV.

In the meantime I just have to avoid multiples of 200 kHz when whatever it
is is being used.

Dave

"Edmund H. Ramm" wrote in message
...
In "DougSlug"
writes:

I understand about the noise and harmonics a switcher can generate, but
the thing is that my antenna is mounted outside on a mast 25 feet up.
All the wiring in my neighborhood is underground.

The neighbours' tv aerials are also underground? The neighbours'
inhouse mains wiring is underground?

It's not clear to me how I could be getting such strong interference
in this case.

The rf energy creeps up the coax' braid and along the mains wiring and
is radiated from there.

My neighbour once had a switch mode psu which pegged my rx' s-meter
on 80m and was still about S5 1km away (spikes 100Hz apart).

QRM from el cheapo switching psus can possibly be cured on a one by
one basis, as hopefully there aren't too many of them. As all and sundry
have at least one tv set at home, QRM from the line output stages has to
be endured or somehow be reduced at the receiving end (notch filter et
al).
If it's any consolation to you, the latter type of QRM will gradually fade
away as more and more flat-screen tv sets enter homes, and will be
replaced
by a much more horrible QRM when said flat-screen is of the plasma
variety.

73, Eddi ._._.
--
e-mail: dk3uz AT darc DOT de | AMPRNET:
If replying to a Usenet article, please use above e-mail address.
Linux/m68k, the best U**x ever to hit an Atari!