October 2007 - AMSAT-BB - mailman.amsat.org

AO-7 Events.
by John Hackett 11 Oct '07

11 Oct '07

Here are the events for the 50576 pass. 08:37 ... AOS but nothing heard from the transponder. 08:38 ... Normally, I would have a strong downlink now but still nothing heard. 08:38:26 Very faint downlink signal. 08:39 ... S3 08:40 ... S3 for the entire pass. This time we can "assume" the satellite is in mode-C. Interestingly, once again, the solar array was (theoretically) in full sunlight but the footprint was 90% in darkness at AOS when the transponder is supposedly OFF. I have no logical excplanation for this. 73 John. <la2qaa(a)amsat.org>

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The laws of physics.
by John Hackett 11 Oct '07

11 Oct '07

Due to it's somewhat erratic behaviour this past week I have been monitoring AO-7 even more closely than usual. There has been some controversy as to which mode ... B, C or OFF ... AO-7 is in at certain periods in the same orbit. Here are a few points to ponder. This is a good opportunity to test your receiving system. Some stations report the satellite as being OFF when they can't hear their own downlink ... whereas others, at the same time/same orbit report it as being ON but in mode-C ... (low power) ... this is *NOT* a comment on SV1BSX's report of the satellite being OFF ... because I experienced exactly the same thing myself this morning at 11-10-07 at AOS. AOS ... nothing heard ... (and I gave *GOOD* antennas) ... but soon after the "footprint" crossed the grey line, in both IT and NOVA ... (I was monitoring both) ... my own downlink was audible AND INCREASED PROGRESSIVELY AS THE SATELLITE APPROACHED THE HORIZON (LOS)... that is to say ... the range increased and the signal became stronger. For obvious reasons, THIS DOES *NOT* SUGGEST MODE-C. The laws of physics *DON'T* change ... however, propagation and other parameters do. Mode-C. It is possible that the 30+ year old solar panels are producing enough power to run the transponder at 2 watts since they've been producing adequate power to run the transponder in mode-B ... whatever that power is these days ... (unknown) ... but it's still hyperthetical as to which mode the satellite is actually in at AOS. If anyone has any coherent explanations please share them with us because once again AO-7 is continuing to dish out surprises and the old girl can teach us all something valuable for future satellites. NB. It's interesting to note that when the *footprint* crosses the grey line ... (a phenomenon I've monitored for several days now) ... the solar panels are in full illumination ... (theoretically !!!) ... but the transponder appears to be OFF and switches ON just as the footprint crosses the line. A coincidence? ... I think not, but I don't have a "sensible" explanation. Explanations are invited to EU-Amsat. 73 John. <la2qaa(a)amsat.org>

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Re: Foxhunting via satellite - additional
by Trevor 10 Oct '07

10 Oct '07

Also see Transmitter Hunting: Radio Direction Finding Simplified By Joseph D. Modell http://books.google.com/books?id=RfzF2-fHJ6MC&pg=PA308&lpg=PA308&dq=%22osca… 73 Trevor M5AKA --- Trevor <m5aka(a)yahoo.co.uk> wrote: > First demonstrated on OSCAR-6 see > > (WO/1999/041723) APPARATUS AND METHOD FOR LOCATING MISSING PERSONS, ANIMALS, > AND OBJECTS > http://www.wipo.int/pctdb/en/wo.jsp?IA=WO1999041723&DISPLAY=DESC > > "Animal tracking tags using Ultra High Frequency (UHF) Transmitters provide > long-range tracking through orbiting satellite receivers by using very low > data > rates. The low data rates allow the use of very narrow bandwidths to > communicate the animal's identification and to determine the animal's > position > by measuring the Doppler shift of the transmitter's carrier. This technique > was > first demonstrated using the OSCAR 6 amateur radio satellite and has been > used > to locate Emergency Locator Transmitters (ELT) from downed aircraft and > hikers. > Unfortunately, narrow band systems can only service a limited number of > tags." > > 73 Trevor M5AKA > > > > > > > ___________________________________________________________ > Want ideas for reducing your carbon footprint? Visit Yahoo! For Good > http://uk.promotions.yahoo.com/forgood/environment.html > ___________________________________________________________ Want ideas for reducing your carbon footprint? Visit Yahoo! For Good http://uk.promotions.yahoo.com/forgood/environment.html

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Foxhunting via satellite
by Gould Smith 10 Oct '07

10 Oct '07

I am giving a presentation about satellite tracking software to the local club next week. Their theme for the year is fox hunting. I thought I remembered that some time in the past there was talk of or an actual event that took place of doing a foxhunt via amateur satellite. I seem to remember something about transmitting a tone and using the shift to determine the location. Now this may be a couple of cross synapes and I am getting my stories mixed. If anyone knows of any such event or better yet participated in one, please let me know and pass along some of the particulars. Thanks, Gould, WA4SXM

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AO-51 PBBS ON, L/U mode
by Mineo Wakita 10 Oct '07

10 Oct '07

WiSP, Up 1268.700 MHz, Down 435.150 MHz, 9600 bps, KISS http://www.ne.jp/asahi/hamradio/je9pel/ao51pbbs.htm de JE9PEL, Mineo Wakita

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FS - ICOM IC-1271E 23cms multimode - UK Only please.
by Dave Aitch 10 Oct '07

10 Oct '07

All in working order, boxed, manuals, microphone, including service manual. Asking £495:00 Got SKYPE ? See it working ! Cheers, Dave.

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3Z50SPU celebrating the 50th anniversary of SPUTNIK-1
by Trevor 10 Oct '07

10 Oct '07

3Z50SPU celebrating the 50th anniversary of SPUTNIK-1 http://www.southgatearc.org/news/october2007/3z50spu.htm 73 Trevor M5AKA --------------- Daily Amateur Radio RSS News: http://www.southgatearc.org/ Email your news items to: editor at southgatearc.org News On Your Website: http://www.southgatearc.org/rss/index.htm News On Your PC: http://www.southgatearc.org/rss/newsreader.htm Upload Your News: http://www.southgatearc.org/news/your_news.htm --------------- ___________________________________________________________ Want ideas for reducing your carbon footprint? Visit Yahoo! For Good http://uk.promotions.yahoo.com/forgood/environment.html

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Sputnik at the NAtional Archives: Thurs 10/17
by Eric Rosenberg 10 Oct '07

10 Oct '07

For those in the DC area and (still) interested in Sputnik, this event (author talk) will be taking place at the National Archives here in DC. Enjoy! Eric W3DQ ------------- *Wednesday, October 17, at noon Jefferson Room /Red Moon Rising/* To mark the 50th anniversary of Sputnik, Matthew Brzezinski discusses his new book, /Red Moon Rising: Sputnik and the Hidden Rivalries That Ignited the Space Age. /Using original interviews and new documentary sources from both sides of the Cold War, Brzezinski tells how the Soviet Union created Sputnik in response to its inability to shoot down America’s U-2 spy planes that flew regularly over Soviet territory. The launch, on October 4, 1957, of an artificial satellite that would orbit the earth and cross American skies at will stunned the world. This is a story rich in the paranoia of the time, with combatants that include two future Presidents, survivors of the gulag, corporate chieftains, rehabilitated Nazis, and a general who won the day by refusing to follow orders.

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AO-7 weak signal.
by John Hackett 10 Oct '07

10 Oct '07

Quoting Mika OH8MBN ... a 6dB difference between mode-B and mode-C wouldn't show the difference between a S7/S9 and a barely audible signal. Quite right! Mika. I don't think the satellite was in mode-C at all, I believe it was in mode-B ... but creeping along the "grey line" and therefore *NOT* getting enough sunlight to power the transponder properly. Taking into account the age of the solar panels ... (31 years) ... it's a safe bet that they are *NOT* producing anywhere near what they did in 1974. It's anybody's guess exactly how many watts the mode-B transponder is producing these days. I'd estimate that mode-C would be totally inaudible these days unless you were using an EME class receiving system, however, I am open to debate on this particular point. I have been using QRP for 40 years now and am fully aware of what can be done with decent aerials but it should be remembered that AO-7 is *NOT* equipped with a large array when considering my comment re: power. 73 John. <la2qaa(a)amsat.org>

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AO-51 certificates for Sputnik
by wa6fwf 10 Oct '07

10 Oct '07

Hi All, I have started to receive the requests for certificates and I am working on getting them out as fast as possible. The response has been great so far but I would like to mention a couple reminders... 1)this is not a small QSL card, it is a certificate that is 8.5" x 11", so if you send a small envelope I will be forced to fold it... 2)make sure you have enough postage... 3)if you want to make sure it does not get bent, include a card board backer or use a heavier envelope 4)do not include money or stamps, I appreciate the gesture but it is not necessary, donations can be sent to Martha directly... based on the fact that my mailbox was full and the postman had to leave more at the front door I might need the couple weeks we said it might take! Glad you ALL enjoyed the Sputnik rebroadcast. 73 Kevin WA6FWF

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