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 [email protected] To: AMSAT-BB [email protected] 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 _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Some weeks ago I saw Italian stations running vast amounts of power through a transponder and causing the beacon to modulate heavily, can't remember which satellite it was.
In fact these stations were running so much ERP that they took the entire satellite out.
Simon Brown (G4ELI/HB9DRV) http://v2.sdr-radio.com
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected]
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?
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, [email protected] 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 [email protected] To: AMSAT-BB [email protected] 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 _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
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, [email protected] 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 [email protected] To: AMSAT-BB [email protected] 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 _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
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, [email protected] 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 [email protected] To: AMSAT-BB [email protected] 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 _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
participants (4)
-
Darren Long -
g0mrf＠aol.com -
n0jy -
Simon Brown