Re: [amsat-bb] Ground base data signal

[John Wright <g4dmf@xxxxxxxxxxx>]

At 12:55 01/08/01 +0000, you wrote:
>Does any one in the Washington, DC or Virginia area know what kind of 
>ground based data link signal is on 145.305 Mhz? It has modulation that 
>sounds just like the AO40 beacon? It seems to be a SSB signal.
>
>I was really confused Monday evening when I came back from dinner, the 
>AO-40 beacon was gone (found out later that they were uploading Rudak) and 
>when I turned off my S Band downconverter I heard what I thought was the 
>beacon - took a few minutes to realize there was no doppler shift.
>
>The modulation looks very similar to the beacon on AO-40Rcv. It is on a 
>bearing of 240 degrees from here in Strasburg, VA which is looking down 
>the Shenandoah Valley towards Harrisonburg, VA
>

I have a signal that also sounds like , and looks very similar to the AO40 
beacon with AO-40Rcv, on 145.860. I think that it is coming from a cordless 
burglar alarm or telephone system on an industrial unit across the road ( 
can't prove that ! ). It is much stronger out of working hours, and appears 
to slowly drift about 50kHz LF when it changes signal level at 08:30, I 
assume that is when the unit starts working. It gets stronger again at 
about 19:30, once again I assume when the unit closes down. This caused me 
great confusion when the 2 metre beacon was running, as at times it was 
actually on top of the beacon.

Perhaps a bit of detective work is required. Here in the UK, the amateur 
service is " unprotected " and so complaints to the Radio Communications 
Agency are like to be fruitless ( Also you have to pay an up-front fee of I 
think 40 UK Pounds,  about 60 Dollars to start an investigation).


____________________________

      G4DMF  QTHR   IO93ha
      Amsat-UK Member 5372
          g4dmf@amsat.org
        g4dmf@g4dmf.co.uk
      http://www.g4dmf.co.uk
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