John, The December 1974 issue of the AMSAT Newsletter covered AO-7 telemetry fairly in depth. Included was a description on reading the telemetry followed by a telemetry conversion table. You can find the issue in Phil Karn's archive http://www.ka9q.net/AMSAT-Newsletter-1974.pdf The article begins at about page 100 of the PDF
EMike EMike McCardel, KC8YLD VP for Educational Relations AMSAT-NA Sent from my iPhone > On Jul 31, 2014, at 2:26 PM, John Papay <[email protected]> wrote: > > It is very rare to hear clear CW from the AO-7B > telemetry beacon around 145.972. Most of the time > there is no beacon at all. Sometimes there is > jibberish. Usually the signal is very weak. > > With AO-7 going through eclipse on every orbit, the > satellite can come out of eclipse in different modes/ > options. Recently there have been times where the > beacon has transmitted clear CW over North America, > something I have not heard over the years. > > According to the DK3WN website, there was some cw > telemetry back in 2002 when the satellite was discovered > to be working again. And there was some discussion about > what is valid data based on the last 3 digits sent in the > 24 group block of data. If the value is 649, 650, or 651, > the data is likely valid. > > I first heard the image of the cw signal around 958. It was > so loud I thought it was a valid user at first. But since > the cw was all numbers I tuned up to the beacon frequency and > there the signal was louder than anything I have ever heard > on AO-7. It took a while for me to get the recorder running > but I managed to capture some data. After playing it back I > found that there was only one block of data where the last > group was valid, a 649. Other later transmissions were loud > but the data was much different and the last group was not > correct. > > I couldn't locate a telemetry calculator at first so I decided to > build one on Excel using the formulae provided by DK3WN. The > data follows: > > AO-7B Telemetry 24July2014 2318UTC > POS Parameter Range Raw Real > > 1A Total Solar Array Current 0-3000ma 171 2094.5ma > 1B +X Solar Panel Current 0-2000ma 193 110ma > 1C -X Solar Panel Current 0-2000ma 157 830ma > 1D +Y Solar Panel Current 0-2000ma 108 1810ma > 2A -Y Solar Panel Current 0-2000ma 286 250ma > 2B RF Power Out 70/2 0-8watts 204 7.3728W > 2C 24 Hour Clock Time 0-1440min 201 15.16min > 2D Batt Ch/Discharge Current-2000/+2000 207 -1720ma > 3A Batt Voltage 6.5-16.4 361 12.7V > 3B Half Batt Voltage 0-10v 397 9.7V > 3C Batt Charge Reg #1 0-15v 340 6V > 3D Batt Temperature -30 to +50C 300 95.8C > 4A Baseplate Temperature -30 to +50C 446 27.72C > 4B PA Temperature 2/10 -30 to +50C 401 94.32C > 4C +X Face Temperature -30 to +50C 430 51.4C > 4D +Z Face Temperature -30 to +50C 498 -49.24C > 5A PA Temp 70/2 -30 to +50C 545 29.2C > 5B PA Emitter Current 2/10 0-1167ma 502 92.84MA > 5C Module Temp 70/2 -30 to +50C 543 32.16C > 5D Inst. SW Regulator 0-93ma 527 33.14MA > 6A RF Power Out 2/10 0-10,000mw 606 23.076MW > 6B RF Power Out 435 0-1000mw 643 219.9MW > 6C RF Power Out 2304 0-100mw 679 255.881MW > 6D Midrange Telemetry Cal 0-.5v 649 0.49 > > There are some values which are obviously not correct. > Some sensors might not be working properly since some > values are out of range. However, the solar panel numbers > might be somewhat correct. I wouldn't doubt it if the > transmitter was putting out 7 watts at the time. > > Perhaps there are those who are familiar with the AO-7 > telemetry that can make some sense out of the data. > Unfortunately we don't have multiple blocks of good data > to compare readings. Maybe some have recorded recent CW > data and can find some good blocks that can be shared here. > > The data was copied on my Arizona remote and Skype was being > used to listen. But I am fairly confident that the cw copied > is correct. > > 73, > John K8YSE > > > > > > > _______________________________________________ > 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
