@radiofreqs How is AO-7 these days? What is the proper current etiquette / method of working this grand old bird? I’ve read about this, but most such primers are years old. I’d not like to over draw hims old linear transponder if I give it a go. Thanks!

@Shufei I haven't had the pleasure of working AO-7. I checked with a friend who regularly works birds, and he hasn't worked AO-7 either.

Any fedi-hams have information on working AO-7?

#hamradio #amateurradio #satellite

@Shufei Just today there was some information sent out by AMSAT regarding AO-7.

"AO-7 to Enter Full Illumination Period October 9, 2019

"On or about October 9th, AO-7 will enter a period of full illumination that will last until approximately December 2nd. During this time, the satellite’s onboard timer should switch it between Mode A (145 MHz uplink / 29 MHz downlink) and Mode B (432 MHz uplink / 145 MHz downlink) every 24 hours. To check or report the satellite’s current mode, please see the AMSAT Live OSCAR Satellite Status Page at

"Reporting observations during the first few days of the full illumination period will be helpful for determining the approximate time of the daily mode change.

"Historical information on AO-7’s systems, including the functioning of the 24 hour timer, and operational plans can be found in the AMSAT-OSCAR 7 Technical Operations Plan And Experimenter’s Guide, available at

For others that might be interested:

"AO-7 became non-operational in mid 1981 due to battery failure . In 2002 one of the shorted batteries became an open circuilt and now the spacecraft is able to run off solar panels. For this reason it is not usable in eclipse and may not be able to supply enough power to the transmitter to keep from frequency modulating the signal. When continuously illuminated, the mode will alternate between A and B every 24 hours.

In a few days the satellite will be entering and prolonged period of continuous illumination, from about 9-Oct to 2-Dec.


#hamradio #amateurradio #satellite #AO-7

@radiofreqs Time to meet the granddaddy of all amsats. I figured he would be in sunlight soon. Thanks heaps!

@radiofreqs Yay, we get to play with Oscar 7 again, yay. I shall give him a whirl if I can figure out a good setup for whichever mode he is using this time. He has such a funky band split.

Thank you for remembering my inquiry! It’s amazing this lil robot is still working!

@Shufei it is a funky band split. And it changes every 24 hours. I will have to use an SDR for downlink when it is on 10m.

Which makes me realize with the websdr sites, anybody can listen in on the fun. No license required. And, the downlink can be monitored whenever a websdr receiver is in the footprint.

@Shufei what we need is a bot that will post a link to websdr receivers as AO-7 becomes visible.

@radiofreqs That’s heaps of posts, though, as there are so many! But it is a jolly good idea. AO7bot? Like, just him announcing which area he will be in soon? It can’t be too hard, as it’s only one TLE to process against coordinates. Hmm.

I use the usual satellite softwares to track him.

@radiofreqs Oh, yay, you are right! Yes, thanks heaps! I shall use the sdr network to chase him and talk to him too.

I MARS mod my radios on general principle for just these eventualities, but would fancy a tx/rx sdr at some point. HackRF One/Blue was nice when I last looked. Any suggestions?

I think... my 10m whip might talk to him. But maybe cutting a dipole and setting up as inverted v is better. Funtimes.

@Shufei HackRF is good. LimeSDR is another. I have an Analog Devices PLUTO which doesn’t cover HF, but is useable for VHF and UHF. But needs an external PA. RedPitya is another option as well.

@Shufei the SatNogs observation reports are useful in that some contain waterfalls plots (where the Doppler shift is quite apparent) and audio.

@radiofreqs Oh, that’s a new site for me, ta! I like they included the Doppler edges for freqs.

Do you know of any way to decode the telem? I think I wrote one of the AO-7 devs back in the day for a primer but never heard back from him.

@Shufei @radiofreqs I don’t know anything about the telem decode. But if I get a chance I will look into it.

@nonlinear @radiofreqs Ta. The flight controller uploaded some telemetry sheets with his listserv reports back in 200X when they refund AO7 again. It was interesting and his surprise was palpable. I’ll try to refind...

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