That makes sense Hector. I've seen the FM activity kind of all over the transponder. More so than I would expect if it was the same transmitter each time on the same frequency and the different pass geometries causing a bit of swing due to doppler.
-Zach, KJ4QLP
On 11/08/2015 06:34 PM, Hector W5CBF/CO6CBF wrote:
Hi Zach and group
I think, the main problem is they are not always the same stations. I have heard several different stations in terrestrial QSOs QRMing FO-29; majority of them speaking Spanish and without any kind of ID. I have not heard them recently, though.
73!
Hector, CO6CBF/W5CBF
-----Mensaje original----- De: AMSAT-BB [mailto:amsat-bb-bounces@amsat.org] En nombre de Zach Leffke Enviado el: Sunday, November 08, 2015 4:54 PM Para: amsat-bb@amsat.org Asunto: Re: [amsat-bb] FM signal on FO-29?
well.. when I say students, I meant graduate students at VT that happened to be in the lab when I was doing the experiment. They work with me and Bob, so a few crude words here and there aren't uncommon to them.
But good point, probably not the best thing for a public demo if your audience is a bit younger.
Actually, I've seen so much FM activity (basically every time I've monitored FO-29 since we first came online in late september) that I've been toying with the idea of trying to locate where the source emitters actually are located based on doppler shift data. We know the doppler between the receiving ground station and FO-29, so we can back that out. We know the transponder mapping, so we can work through that to determine what the center frequency is as the signal enters the transponder uplink receiver. What we don't know is the uplink doppler, because we don't know where the emitter is and we don't know what exact center frequency they are on (but I bet you its in 5kHz steps, maybe 2.5kHz). So we have two unknowns. I'm betting there's a way to work through it though, and with enough observations and by watching the rate of change of the doppler, I bet there's a way to make an educated guess on what their center freq and location are.
Or if someone listening knows Spanish and/or Portugese, maybe we could get lucky and hear what cross streets the taxi is going to (if it is in fact a taxi).
-Zach, KJ4QLP
On 11/08/2015 05:30 PM, Clayton W5PFG wrote:
I wouldn't recommend playing the FM audio heard via FO-29 to a group of children. Normally it's not English. It's most likely NOT a religious broadcast based on their choice of crude words.
73 Clayton W5PFG
On 11/8/2015 16:13, Zach Leffke wrote:
So yes, in the last couple weeks I've seen a LOT of FM activity on FO-29. And based on my experience with Friday's pass, which was ascending, I'm leading towards the Central/South America QRM theory. Lots of strong FM activity as the pass started and the satellite was over the lower latitudes, but as FO-29 ascended over higher latitudes towards the north pole, the FM activity died down.
-Zach, KJ4QLP
Sent via AMSAT-BB@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
Sent via AMSAT-BB@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