I live about 2 miles from San Francisco International airport.
And I get a kind of annoying interference all up and down the SW
bands, although perhaps a little stronger on the higher frequency
end. Kind of a "schwufff... schwufff... schwufff..." that
repeats every second or so. It must be at a pretty low level
since it drops away when I catch a strong station.

Also, I haven't heard that at all on my scanner (FM, tho, I
know.)

First guess that now seems unlikely was the airport radar.
Thought of that because of the periodic nature of the noise. And
yes, I've shut down everything in the house by opening the main
breaker (had to do that for a repair anyway) and still got the
rfi.

Any guesses out there?



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In article ,
Lars Janqqvist wrote:
I live about 2 miles from San Francisco International airport.
And I get a kind of annoying interference all up and down the SW
bands, although perhaps a little stronger on the higher frequency
end. Kind of a "schwufff... schwufff... schwufff..." that
repeats every second or so. It must be at a pretty low level
since it drops away when I catch a strong station.

Also, I haven't heard that at all on my scanner (FM, tho, I
know.)

First guess that now seems unlikely was the airport radar.
Thought of that because of the periodic nature of the noise. And
yes, I've shut down everything in the house by opening the main
breaker (had to do that for a repair anyway) and still got the
rfi.

Any guesses out there?

Yes. My best guess is ultrasonic pest repellers.

I started getting this about a month or two ago, which I blamed on
Over The Horizon surveillance radars. (I even dug up some web pages
at Raytheon on these systems, which they're hawking for the Homeland
Security business and for intercepting drug runners. Interesting stuff).

It shows up above 10 MHz, peaking around 12 and 18 MHz, but it also
shows up on the vacant areas of the FM audio broadcast band, and really
shows up on Channel 4 on the TV. (I'm one of a vanishingly small number
of people who use a rooftop TV antenna in my part of town). It shows
up on the TV screen (in the black areas of the picture) as about a 1
millisecond burst of 60-100 kHz digital pulses every second or so.

SO I took my portable (FR-200) receiver for a walk around the neighborhood
and found that it was heard only within about a half a block of my
neighbors that live above me on the hillside. Confirmed by a peak in
the interference when rotating the TV antenna.

I thought it might be some equipment like computer network gear, but
there was no sign of any intelligent modulation, or perhaps some sort
of smart battery charger.

Then I ran across this a junk mail catalog I had. Home Trends,
www.shophometrends.com (visit at your own risk ;-) ).

Sunbeam brand pest repellers "DRIVES PEST AWAY
This dual technology Pest Repeller uses both Ultrasonic and
Electromagnetic technology to help fight against pest. Use against mice,
rats, ants, and spiders. Built in AC Outlet, night-light and digital
clock are for added convenience. Plugs into any standard 110v outlet.
One unit recommended for large size room. UL listed. Cannot ship to
all states." $34.95, 2/$65

There are other (cheaper) ones that don't mention "Electromagnetic
technology", too.

I wonder if the FCC and FTC know about this CRAP.

Mark Zenier Washington State resident

I know somebody probably just a mile or two from you that complains
about something similar to that and says a lot of it is contributed to
DSL. Sounds odd, but she's convinced of it and is quite clever in the
electronics field.

Lets just hope you don't have that bull**** BPL being tested there.


On Sun, 21 Nov 2004 16:11:07 GMT, Lars Janqqvist
wrote:

I live about 2 miles from San Francisco International airport.
And I get a kind of annoying interference all up and down the SW
bands, although perhaps a little stronger on the higher frequency
end. Kind of a "schwufff... schwufff... schwufff..." that
repeats every second or so. It must be at a pretty low level
since it drops away when I catch a strong station.

Also, I haven't heard that at all on my scanner (FM, tho, I
know.)

First guess that now seems unlikely was the airport radar.
Thought of that because of the periodic nature of the noise. And
yes, I've shut down everything in the house by opening the main
breaker (had to do that for a repair anyway) and still got the
rfi.

Any guesses out there?

Frightening the yaks, JuLiE Dxer just had to say:

I know somebody probably just a mile or two from you that complains
about something similar to that and says a lot of it is contributed to
DSL. Sounds odd, but she's convinced of it and is quite clever in the
electronics field.

Lets just hope you don't have that bull**** BPL being tested there.

We're pretty well saturated with DSL and cable modems around
here. BPL would have a tough existing field to fight against.

Which is not to say that PG&E *isn't* testing something. Might
as well do the work where the engineers are.

I have a neighbor who works for PG&E and can usually dig up the
real deal about stuff they're up to. I'll check with him and see
what he has to say about it.



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To reply, DO NOT remove spam from the return address!

***************************
This calls for a careful blend of
clever psychology and extreme violence.
***************************

Frightening the yaks, Mark Zenier just had to say:

Yes. My best guess is ultrasonic pest repellers.
[SNIP]
Sunbeam brand pest repellers "DRIVES PEST AWAY
This dual technology Pest Repeller uses both Ultrasonic and
Electromagnetic technology to help fight against pest. Use against mice,
rats, ants, and spiders. Built in AC Outlet, night-light and digital
clock are for added convenience. Plugs into any standard 110v outlet.
One unit recommended for large size room. UL listed. Cannot ship to
all states." $34.95, 2/$65

There are other (cheaper) ones that don't mention "Electromagnetic
technology", too.

I wonder if the FCC and FTC know about this CRAP.

That's something I never would have guessed.

How much circuitry does a device have to have before Part 15
applies? It'd be interesting to get one to play with, and see
just how noisy the little suckers really are.


Oh, I noticed something else with the RFI I'm getting... I was
trying to zero in on a SSB signal, and from the pitch sweep it
sounded like the RFI "carrier" was sweeping up or down the
bands...

Just FYI, I have a 7600GR with an AN-LP1.

Always something odd... keeps it interesting.




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clever psychology and extreme violence.
***************************

Oh, I noticed something else with the RFI I'm getting... I was
trying to zero in on a SSB signal, and from the pitch sweep it
sounded like the RFI "carrier" was sweeping up or down the
bands...

Just FYI, I have a 7600GR with an AN-LP1.


Sounds like your 7600gr is in Sync mode and your tuning a SSB signal.
While the Sync tries to Lock onto a non-existent AM carrier you will here
a sweeping sound as the Sync "seeks" the non-existent AM carrier.

Frightening the yaks, 0ff_r/-\/\\p just had to say:


Oh, I noticed something else with the RFI I'm getting... I was
trying to zero in on a SSB signal, and from the pitch sweep it
sounded like the RFI "carrier" was sweeping up or down the
bands...

Just FYI, I have a 7600GR with an AN-LP1.


Sounds like your 7600gr is in Sync mode and your tuning a SSB signal.
While the Sync tries to Lock onto a non-existent AM carrier you will here
a sweeping sound as the Sync "seeks" the non-existent AM carrier.


Hmmm... the frequency sweep was at (I'd say almost exactly) the
base period of the RFI as heard on straight AM.

Any chance that there's a problem with the radio itself? It'd be
one of those obnoxious intermittant problems then.



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Any chance that there's a problem with the radio itself? It'd be
one of those obnoxious intermittant problems then.


There is always a chance. Be sure to read the manual about SSB and Sync
mode.
I suspect the problem is Operator Error ;-)

Turn the mode switch to the Normal position while tuning.
Switch to Sync mode only when you wish to Lock in an AM station and listen
to the program.
Sync mode can not function when trying to hear a LSB or USB SSB signal such
as Ham or utility stations.
Sync mode requires an AM carrier to lock which SSB (LSB/USB) does not
provide.

In article ,
Lars Janqqvist wrote:
Frightening the yaks, Mark Zenier just had to say:

Yes. My best guess is ultrasonic pest repellers.
....
Oh, I noticed something else with the RFI I'm getting... I was
trying to zero in on a SSB signal, and from the pitch sweep it
sounded like the RFI "carrier" was sweeping up or down the
bands...

Yea, that sounds just like the stuff I'm getting, too. As I understand
it, the pest repellers sweep the frequency up and down to maximize the
irritation. It gets real bad at 12095 kHz where the sweep turns around.

Just FYI, I have a 7600GR with an AN-LP1.

It's a portable, go on a walkabout. If it't the same thing as I'm
hearing, it only goes for a half a block or so, and you'll roughly
able to find where it's strongest. One trick I found using my
FR-200, which doesn't have any sort of signal strenght indicator,
is to tune to relativly stable broadcast signal to set the AGC in
the receiver, and then you can see when the interference gets louder
or softer.

Mark Zenier Washington State resident