Yep I'm definitely hearing stations again tonight, even with the preamp
off. It may be an image, I can see the same QSO up higher on the
spectrum display at about the same offset from the center frequency
145945 so that would make it about 145957 or so (give or take late night
calculating) and that is in the transponder window. Stations appear much
stronger on the spectrum display than the rest of the bumps.
Jerry
N0JY
On 12/6/2013 10:37 AM, Darren Long wrote:
I also observed something like this the other day. I wondered about its
cause, but as I was actually doing something else at the time, I
completely forgot about it.
There were, as you note, strong SSB signals around the beacon freq
during the AO-73 pass.
Cheers,
Darren, G0HWW
On 06/12/13 15:47, n0jy wrote:
Good thought, David. I do have the settings FCD Centre Frequency set
for 145945. But I also have the auto tune range limited to 34599-44854
kHz which should only let the auto tune catch approximately 145931 to
145941 kHz. So it should not be (nor do I observer it to) tuning any of
the transponder portion. It is always locked on the beacon as
identified by the hump and beep "spikes" as I watch it.
I do not hear FMing on the beacon. It sounds like it should, but it is
covered by a stronger SSB signal, basically. And it appears that the
combined doppler shift of the beacon and the signal make them move
across each other such that the QSO eventually passes by but then
another can come up and do the same.
Overloading the FCD maybe? I do have a preamp on, maybe I'll try it
tonight without the preamp. The reason I use the preamp is that when I
initially set up, I could not get a solid spectrograph (it blinked on
and off) unless I had the preamp on. I believe that was related to the
version of Dashboard I had at that time as observed by a friend who had
seen the same thing when he just got his FCD Pro + the other day, but it
disappeared when he upgraded his Dashboard. Preamp is off now, I will
see what happens this morning and tonight.
73
Jerry
N0JY
On 12/6/2013 2:47 AM, g0...@aol.com wrote:
That's an interesting observation Jerry. Not something we saw during
commissioning the satellite.
A possible cause would be image response of the dongle. Do you have
the 'zero frequency' somewhere between the beacon and the transponder
passband? e.g. 145.945 or off to one side e.g. 145.920?
Other possibility is a large signal in the transponder passband
causing the beacon to FM. Is the modulation 'FM' or does it decode
as SSB?
Thanks
David G0MRF
-----Original Message-----
From: n0jy <n...@n0jy.org>
To: AMSAT-BB <amsat-bb@amsat.org>
Sent: Fri, 6 Dec 2013 4:40
Subject: [amsat-bb] AO-73 QSOs on the beacon?
During the eclipse passes while copying telemetry with my Funcube Dongle
Pro + I am hearing SSB QSOs on the beacon frequency.
They usually "walk" across it but what puzzles me is that the website
info indicates that the transponder passband is well away from the
beacon frequency.
Am I experiencing some weird stuff with my Dongle or is it possible for
stations to work on an uplink that puts their downlink on the beacon
frequency?
Thanks,
Jerry
N0JY
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