Sorta on the same order as the 432mhz ground station terrestrial stations messing with AO-7 in mode B. There though we are blessed with extra bandwidth on the linear translator vs single channel FM repeater. HO-68 is a PITA to work on FM for me, but great linear bird.
John W6ZKH
________________________________ From: Bob Herrell nk7i@yahoo.com To: amsat-bb@amsat.org Sent: Sun, October 24, 2010 3:02:24 PM Subject: [amsat-bb] Re: AO-51 short experiment
Alan,
I agree with you totally. It is going to be an ongoing problem and unless individual operators take responsibility for their emissions, it is going to continue. Even with coordination the frequency is still not owned by any particular station. It is just common courtesy that we need to show to each other. Are these APRS stations just beaconing in hopes of hitting the ISS or are
they in use for normal APRS? I don't see 145.825MHz being used as a terrestrial frequency. I can understand the problem when HO-68 and the ISS are in the same footprint, but to run a station continuously on 145.825MHz is crazy. I do send packets to the ISS myself, but ONLY when it is in view and turned on. It all boils down to the old idea of "Listen before you talk".
73, Bob AJ5C
________________________________ From: Alan P. Biddle APBIDDLE@UNITED.NET To: Bob Herrell nk7i@yahoo.com; amsat-bb@amsat.org Sent: Sun, October 24, 2010 3:45:18 PM Subject: RE: [amsat-bb] Re: AO-51 short experiment
Bob,
145.825 is the "established" space APRS frequency, and has been/is used by more than just the ISS for years. There are other APRS satellites which are intermittently active on the same frequency, and I expect there will be others in the future. I can't address the formal coordination issue, but anything with an uplink on that frequency is guaranteed to have problems. The only question is whether those problems are tolerable. There is little to no APRS activity on that frequency over most of the world, and then there is the question of both HO-68 and the ISS being in the same footprint. The HO-68 has an inclination of about 102 degrees, the ISS about half that. Finally, the ISS is not active on that frequency 24/7. It operates on other frequencies for voice and SSTV, and is often QRT completely due to other operations. In an imperfect world, it looks like a reasonable tradeoff, though other evaluations are certainly possible.
The problem of unattended APRS beacons does cut both ways. There are some daylight-only APRS satellites. When they enter periods of extended illumination, they can be commanded from their default modes. However, even a single "braaap" can pull the DC busses low enough that the command stations need to start over again. WB4APR has lamented this problem, with specific calls, in other venues. Looking at some of the paths, both in Drew's example and my reception, there are stations whose paths have not been updated for years.
The sort of courtesy/coordination issue is not limited to space operations. A ham relatively local to me fired up a propagation beacon on 30 meters this month. It is/was within 200 HZ of an APRS frequency which has been in use for some time. Quite a fight over who "owns" the frequency. ;)
Alan WA4SCA
_______________________________________________ Sent via AMSAT-BB@amsat.org. 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