In Germany such signals often came from oscillating TV antenna preamps,
long forgotten and out of use on top of a roof, but still
powered.usually the BNetzA (the regulation authority) was very helpful
in finding those.
From: [email protected]lid
[mailto:[email protected]lid] On Behalf Of
Sent: Tuesday, 10 December, 2013 04:26
To: Patrik T.
Cc: gnuradio mailing list
Subject: Re: [Discuss-gnuradio] Need help identifying jammer signal
Thank you for your helpful suggestions. We still haven’t managed to
pinpoint where the signal is coming from, but we have just dispatched a
black SUV with a three letter acronym stencilled on it (our university’s
initials) to hunt for the signal with a spectrum analyzer and a yagi.
Yesterday the interference was a 440.4 MHz and during the night it went
down to 440.0 MHz. Today it has drifted up and down between 440.0 and
440.2 MHz. This is very annoying as our frequency is 440.2 MHz. Based in
the wild fluctuation in center frequency (including > 20 kHz jumps),
However, the signal at close inspection kind of looks like FSK, so maybe
whatever it is, isn’t working properly anymore.
I recorded a 10 second snippet of 50 kHz baseband signal in interleaved
I and Q with 32-bit floating point format. In python, one would read
this with this command:
z = numpy.fromfile(“rfi.bin”,dtype=numpy.complex64)
The file can be downloaded here:
You can probably feed this into gnuradio with the filesource and complex
Patrik, you are doing cool stuff with the POES satellite receiving. I
wish I had time to try that at some point.
On Sun, Dec 8, 2013 at 5:38 AM, Patrik T. [email protected]
Some animal neck collar TX:er are very close to that feq (440 MHz).
It could be on a wolf, reindeer or a hunter that use a home brew
(illegal) collar on his dog. Building a home brew dog collar is
popular today since you can get parts without any questions asked…
I would contact the person who count wolfs near you.
Eagles here (Vaasa, FI) use ARGOS up-link to POES sats 401.65 and
downlink 465.98 MHz (bw 24/80/110 kHz).
On Fri, 2013-12-06 at 13:48 -0500, Juha V. wrote:
I’ve attached a GRC plot of the signal. In the plot, the jammer is at
a +166 kHz offset. The scope plot is centered at this frequency and
has a 40 kHz bandwidth.
Does anyone have any idea what this could be?