Greetings,
Is the ARRISat-1 CW signal on 145.919 MHz an "A1" mode or an audio tone on an FM signal?
73, Carl Zelich, AA4MI, _aa4mi@arrl.net_ (mailto:aa4mi@arrl.net) AMSAT Member 36366, _AMSAT_ (http://www.amsat.org/) - The Radio Amateur Satellite Corporation
_QRZ AA4MI_ (http://www.qrz.com/db/aa4mi)
Hi Carl,
It's "A1" mode.
73, Tony AA2TX ---
At 08:48 PM 4/9/2011, Aa4mi@aol.com wrote:
Greetings,
Is the ARRISat-1 CW signal on 145.919 MHz an "A1" mode or an audio tone on an FM signal?
73, Carl Zelich, AA4MI, _aa4mi@arrl.net_ (mailto:aa4mi@arrl.net) AMSAT Member 36366, _AMSAT_ (http://www.amsat.org/) - The Radio Amateur Satellite Corporation
_QRZ AA4MI_ (http://www.qrz.com/db/aa4mi) _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Right, it's conventional CW, mode A1, with the carrier switching on and off. A2 would be considerably less power-efficient.
ARISSat-1 also uses the CW beacon as a tuning reference for the BPSK-1000 digital beacon. The BPSK beacon is centered 1 kHz above the CW beacon so that the CW beacon sits in the lower spectral null of the BPSK signal, i.e., in a narrow spot where there's no BPSK signal power.
If you put your receiver in USB mode and tune the CW beacon so it comes out at an audio frequency of 500 Hz, this will automatically center the BPSK signal in a conventional SSB filter extending from 300-2700 Hz.
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