August 2011 - AMSAT-BB - mailman.amsat.org

Decoding wideband recordings
by Phil Karn 19 Aug '11

19 Aug '11

It's been suggested that I modify my ARISSat-1 BPSK-1000 telemetry demodulator/decoder to accept wideband quadrature (I & Q) recordings like those produced by most of the software defined radios out there. This is fundamentally not that hard, but first I need some information. How many people could actually use this? What is the format of the recorded files? Is there a standard, or does each make of SDR produce its own? If I could get a good sample wideband quadrature recording of the ARISSat-1 downlink that includes the BPSK beacon, I could use it for testing. Ideally there would be no need for any manual tuning because the wideband recording would always contain the beacon regardless of Doppler. All tuning would be in the demodulator software. This might be a little compute-intensive so I can't guarantee that it'll run in real time on older computers. I already make pretty heavy use of the Intel SSE (vector arithmetic) instructions for FIR filtering and Viterbi decoding. The SSE2 set introduced with the Pentium 4 has been especially useful, so I would consider the P4 (or the AMD equivalent) a minimum requirement. Of course, the newer and faster the CPU, the better. I also make use of multiple CPU cores, particularly during the acquisition phase, so the newer CPUs with lots of CPU cores would also be preferred. 73, Phil

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Cubesat workshop with Bob Twiggs Nov 11-12
by charlie Cantrill 19 Aug '11

19 Aug '11

Thought some might be interested in this. Kentucky Space announces the first annual hackerSPACE Workshop...focused on CubeSat class satellites: http://www.kentuckyspace.com/pollydoc/hackerSPACE-2.pdf Charlie KI4RDT

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ARRISsat1 pass
by Jim Cameron "KC9PXZ" 19 Aug '11

19 Aug '11

Hi, just had a pass no SSTV this time. bumer! Did get the voice TLM. Speacking of TLM. when you say send TLM to the servier, thats where? I also used scanner recorder to record the pass. It was wierd all I heard in the play back was loud beeps. any thought. I hate not to record the audio, maybe next time i wont record it and see if its better. I have already sent for all three cerf. So I dont need more than one cerf. for each of the three. I dont understand the secret word. Is it just a way to confirm or do we send them in for a drawning or somthing? So If they want Voice TLM I will be glad to send it when I recieve it just not sure were to send it. Also I have the bug, so I am doing to start monitoring TLM on the birds I work when they pass. just not sure were to send it once I have it. 73 KC9PXZ Jimmy

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QRZ and email address
by wa4hfn＠comcast.net 19 Aug '11

19 Aug '11

If you don't already have your email address on QRZ.com callsign lookup, PLEASE go there and add it (if you have one) This is very helpful in making skeds for satellite contacts and sharing info with new ops. Thanks WA4HFN Damon EM55

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Frustrated--not hearing ARRISat
by Burns Fisher 19 Aug '11

19 Aug '11

Hi everyone, Ok, I'm getting very frustrated and I think I need some Elmering. I have not heard ANYTHING from ARRISat-1, at least nothing intelligible. I'm a pretty new ham, so I'm getting into it one piece of equipment at a time. Figured I'd play a bit with a handheld, and then figure out what I needed next step by step. It's been several steps so far with nothing to show for it except some pretty hardware and a smaller bank account. I know a few more things I can do, but I'd really like to know if I have some major problem here. I'll tell you what I'm trying, and I'd like to know if anyone has had success with anything similar. First, I have an M2 2-meter eggbeater antenna. It is inside the house (my shack is on the 2nd floor, sadly). It has an SSB 2-meter pre-amp, followed immediately by a Diamond 2m/70cm duplexer into a 25-foot feed line. At that point it is connected via an adapter to my Kenwood F6A handheld. I also have an FCD, but with its poor 2-meter filtering, I wanted to eliminate one problem. A few minutes ago, there was a nice pass from ARRISat-1 here in FN42 (southern NH ); it was in sunlight and had been for some time, should have been up over 50 degrees elevation. Turned everything on, (oh, yes including a 13.8V power supply for the preamp, fed separately). My radio tunes in .005MHz increments, so I started out at 145.955 and tweaked around up and down, shifting to 145.950 and 145.945 as the sat reached and passed max elevation. I *may* have heard vaguely down in the static a voice. I *may* have heard vaguely down in the static some data that might have been SSTV. I may have imagined it. I *know* I would get better reception outside; I know I would be better off with a directional antenna that had more gain. I can see improving things that way, but is NOTHING a reasonable expectation with this setup? I can receive the NOAA weather station on 162ish MHz (outside the pre-amp's curve but I still get it); I have received the ISS without the preamp (I know that is a lot more power than the sat). So I don't think something is wildly broken. So my question to you is: Have any of you been able to read the sat with anything similar? An eggbeater? I thought I remembered someone receiving on a handheld with a rubber ducky? BTW, someone previous mentioned that I should try listening to some of the other lower-power sats; many of them are 70cm downlink and I have not gotten a 70cm antenna yet. Thanks for any advice or comparisons. Burns W2BFJ

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QSO on Mode A and Invitation
by Luis Quintas 19 Aug '11

19 Aug '11

I Tnx Keith (N4ZQ) for QSO on CW on AO7 Mode A, Orbit 68221 covering 7041 km betewwn our QTHs. I would like to invite other stations from North America willing to attempt a QSO on AO7 on Mode A. My grid locator is FF66TQ. Tnx agn, Best 73 de --luis LU6QI

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Finally success with hearing Arrisat-1
by Patrick E. Farcon 19 Aug '11

19 Aug '11

I used my Arrow II antenna from working the satellites and ran outside with a single HT and my recorder and headphones. I caught a nice pass with 64 degrees at peak and recorded some SSTV and voice telemetry cycles. It was awesome! I know I am late in coming around to this but better late than never since work has me usually all locked up away from home. 73 all! Pat N2VYT FN20un

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What the heck was that?
by N0JY 19 Aug '11

19 Aug '11

ARISSat-1 right now, some very strange sounding telemetry. Started out normal, then a ticking sound not unlike a WWV clock tick, then some CW with an unknown telemetry? signal? I don't have a recorder. Jerry N0JY __________ Information from ESET NOD32 Antivirus, version of virus signature database 6390 (20110818) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com

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ARISSat 23:15UTC
by N0JY 19 Aug '11

19 Aug '11

Well, it appears that the satellite did a reset just as it came in range here (EM12dl). My TLM start at MET 10, which was just after I heard the "strange noises" I hastily put in an email hoping that others might grab a listen. I have not witnessed a reset while monitoring, so perhaps that's what it sounds like. Some ticks, some strange telemetry tones, CW beacon underneath the tones, then the usual telemetry sound and data. So the reset would have been in full sunlight, not a good sign I would suppose. Unfortunately, the telemetry frame I was hearing right before the reset the bird was not in range long enough to have captured it all, or perhaps it quit in the middle of it anyway. Jerry N0JY __________ Information from ESET NOD32 Antivirus, version of virus signature database 6390 (20110818) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com

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AMSAT NE --Southern NY NET
by Dee 19 Aug '11

19 Aug '11

Relayed from Gary WA2AQH--- Please be advised that the Mt Beacon Repeater AMSAT Net will be held at 00:00 hrs UTC and will also be connected via Echo-Link N2EYH-L. Come with all your reports of Arisssat-1 receptions. There is a pass at 23:19 before the Net - Listen on 145.950 +- Doppler It has an elevation of 55degrees and should be easy to listen to. See you on the Net. 73, Dee, NB2F

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