[amsat-bb] Re: AO-73 QSOs on the beacon?

[n0jy]

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, g0mrf at 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 <n0jy at n0jy.org>
> To: AMSAT-BB <amsat-bb at 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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>   
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