[amsat-bb] Re: UO-11 mode S beacon

Clive Wallis list1 at g3cwv.co.uk
Wed Jan 20 04:49:44 PST 2010

Auke de Jong, VE6PWN wrote:

> Just a quick query regarding UO-11's Mode-S beacon at 2401.5.
> In a couple of places I have read that the Mode-S beacon is said to
> "transmit continuously", while others list that beacon as
> "non-operational". I have also noticed that it is listed a few times
> as having been heard(telemetry only) on the "oscar.dcarr.org" site
> inside their database, using Mode-S.
> I am wondering if it is worthwhile to listen for this beacon (using
> my newly installed BBQ-grid antenna), or is it definitely not making
> any noise?

The mode-S beacon is OFF, and has not been heard for many years. The 
status telemetry indicates that only the VHF beacon is ON.

When the mode-S beacon was active, it did transmit continuously, a 
steady carrier, very weak, with lots of Doppler. A trace of telemetry 
modulation has been detected, although this may have been due to 
accidental coupling within the satellite.

If you look on my website, www.g3cwv.co.uk there is an audio clip of 
what it sounded like and a spectro-gram of the signal.  The news archive 
gives details of when it was transmitting mode-S.


               73   Clive   G3CWV

                    Hitchin, North Hertfordshire, UK

More information about the AMSAT-BB mailing list