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

[Paul Stoetzer]

An FM signal with no modulation is theoretically just a carrier, no
different from CW. So it wouldn't really be a problem to send a couple of
quick transmissions to test it out.

FM signals won't harm a transponder, but they will cause a lot of problems
for others trying to use the transponder.

73,

Paul, N8HM

On Thu, Jul 27, 2017 at 17:41 Scott <scott23192 at gmail.com> wrote:

> 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:
>
> http://www.qsl.net/k/k4kdr//files/2017-07-27--2124--CAS-4A.png
>
> 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
> transponder?
>
> Thanks!
>
> -Scott,  K4KDR
>
> ==========================
>
> On Wed, Jul 26, 2017 at 9:31 PM, christy hunter <cchunter3 at mindspring.com>
> wrote:
>
> > 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
> _______________________________________________
> Sent via AMSAT-BB at amsat.org. AMSAT-NA makes this open forum available
> to all interested persons worldwide without requiring membership. Opinions
> expressed
> are solely those of the author, and do not reflect the official views of
> AMSAT-NA.
> Not an AMSAT-NA member? Join now to support the amateur satellite program!
> Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb
>