[amsat-bb] INTERMITTANT DOWNLINK HEARD - CAS-4A transponder freq

Scott scott23192 at gmail.com
Thu Jul 27 21:40:39 UTC 2017

Had hopes of monitoring some voice transponder activity on a high pass of
CAS-4A this evening, but nothing heard.

The telemetry data stream and CW beacon were strong as ever, but nothing
around the transponder downlink.

Image of SDR waterfall:


Question:  in a case like this where the status of a transponder is unknown
and no activity is heard, absent any SSB gear would it be bad to transmit
an FM signal on the uplink just to see if the transponder is in fact
active?  I would never use FM if there was activity, but could an FM
transmission cause any harm just to possibly determine the status of a


-Scott,  K4KDR


On Wed, Jul 26, 2017 at 9:31 PM, christy hunter <cchunter3 at mindspring.com>

> to All, this is to confirm my status report on the website, (in case you
> think it was a mistake)
> on July 27 2017, at about 0047UTC I could hear my downlink, although
> intermittently, during a pass of CAS-4A (using the published frequencies).
> The downlink had good audio (loud and clear), and I could only hear a few
> words of my transmission at a time. I was able to sustain for only a
> portion of the pass. Using 5Watts into a M2 16 el cross element circular
> beam. (436CP16). This pass did NOT coincide with any of the XW sats.
> 73, Christy KB6LTY, DM14

More information about the AMSAT-BB mailing list