[amsat-bb] Re: Can anyone help identify this signal

i8cvs domenico.i8cvs at tin.it
Sun Aug 12 19:27:33 PDT 2012

Hi Tom, W9KE

It was a RADAR signal with a prf (pulse repetition frequency ) of about
400 Hz


It is very common to hear those signals in my QTH close to the see
here in the bay of Naples.

The only cure to eliminate completely this type of interference was to
use a very efficient Noise Blanker like the circuit used into the old
nice receiver DRAKE R-4C with in front of it a VHF or UHF

I tryed many other novadays receivers with their Noise Blankers built
in but the only one capable to cut off completely the interference was
the optional solid state Noise Blanker for the old HF receiver

73" de

i8CVS Domenico

----- Original Message -----
From: "Thomas Doyle" <tomdoyle1948 at gmail.com>
To: <AMSAT-BB at amsat.org>
Sent: Monday, August 13, 2012 12:29 AM
Subject: [amsat-bb] Can anyone help identify this signal

> I was getting ready for a pass today and heard a very disturbing
> signal in the 70 cm satellite band (435.84MHz). The signal was very
> strong. The signal was at least 500KHz wide (max range on spectrum
> scope). The the spectrum looked like FM but the recording was made
> with the receiver set to usb mode. I checked the signal on two
> different receivers (IC-7000 and IC-7600 with a 70cm converter)  to
> make sure it was not a internal birdie of some sort. During the pass
> it wiped out the sat when it was on. Fortunately it went away after
> about an hour. I am fairly sure it was terrestrial as the signal level
> did not change over the hour. Since it was on for only very short
> periods of time it was impossible to point the beam at it.
> Any help identifying the signal type would be appreciated.
> http://www.tomdoyle.org/RX-8-12-2012-435.84MHz%20-%20USB.WAV
> tnx & 73 W9KE Tom Doyle
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