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According to The Previous Slashdot story:

"The suborbital vehicle will attain an altitude of 100 km or 62 statute miles--high enough to be considered 'space'--linger there for a couple of minutes then arc back to Earth some 26 miles down range."

So, they didn't actually launch an Amateur Satellite into orbit (darn!).

But it looks like these guys are trying just that.

Jesus H. Christ, every time Hams do something nifty, dozens of /. weirdoes start complaining "why are HAMS doing this?"

Haven't you all figured out by now that Ham radio ops, by their very nature, are experimenters? As opposed to the average IRC-babbling, first-post posting, videogame-tapping MTV slashdroid?

I don't know of any noncommercial organization that has as many communications satellites in space (see AMSAT).

I also heard a talk last summer which was looking at just this problem -- modelling the probability of failure of launch vehicles. The conclusion was (basically) that the learning curve is very steep -- a company that has had 3 launches (successful or not, as it happens -- the unsuccessful ones go out of buisiness quicker than that) has almost the same reliability as a company that's been launching for many years. There's a pdf linked from the conference page. The main data points are that after the first two launches, new companies have a success rate of 0.88, and established companies, a success rate of 0.89.

Incidentally, that launch pad is about 3 miles from where I'm sitting. I can see it if I climb up on the antenna tower on the roof, but management got mad last time I did that to watch a launch.

I'd just like to put a Direct Connect Hub in space...yeah!

Join AMSAT, and help us open up space to the people!

The big man with an even bigger heart stepped up to the plate for the cause. My bid was $70, but I bet against myself raising it to $80. After that I spent lunch talking to him about his satellite interests, which are pretty cool.

For actually encoding the data into an audio stream, I would suggest googling for Amateur radio data protocols using modulation schemes like MFSK, QAM, Raised Cosine, etc. Hams have been battling the narrow bandwidth problem for a long time, and have come up with many encoding schemes to protect the data against fading, multipath, etc (many of which are also present on cassette recordings). this site gives examples of digital modulation schemes, as well as a link to cool audio samples!

You might also google for "Phil Karn" or "KA9Q" - he's done a ton of work in this field. Also, the AMSAT or ARRL folk may have some info.

As a ham who works satellites I would not just casually give away the 1.2 Ghz band. Rather, I would like to see WiFi move up to the 5 Ghz band rather than 1.2 Ghz. While I sort of agree that 1.2 Ghz is underutilized, 2.4 Ghz is where the primary downlink for AO-40 is located, and used worldwide. The 2.4 Ghz downlink suffers from interference by microwave ovens, and increasingly WiFi appliances, as well as other services near the band. 1.2 Ghz is a good frequency to uplink to the bird, if you have the equipment, though I agree with you that that 1.2 Ghz stations are hard to find and not easy or cheap to set up properly, due to high feedline losses, and lack of commercial equipment easily modifiable to work in the band.

On the other hand, the technology to clean up signals on microwave ovens could be a bonanza for those hams crazy enough to bounce signals off of the moon in the form of a cheap 500 watt transmitter on 2.4 Ghz. Finally moonbouncers will be able to get armchair copy of EME signals without having to visit Areceibo. I don't want to be in the line of fire of that signal though.

It's a sad day for the Amateur Radio Satellite Service. Our birds are shitting the bed left and right. AO-40 is only quasi-operational on whacky bands, UO-14 and AO-27 are gone. RS-12/13 is gone. AO-10 finally died for good.

Actually, can we confirm that AO-27 is dead? According to the latest AMSAT Weekly Satellite Report, it's still operational.

The Saudi-Sats are both working, I made QSOs on both SO-41 and SO-50 over the summer.
AO-7 is still back from the dead, which is really quite amazing. And at least AO-40 is semi-operational. I really need to get some 1.2 and 2.4 ghz equipment.

Although I agree with what you're saying, I think ham radio has advantages over the internet, thus it could have a new life if ham operators would start advertising as such.

For just gabbing, although others can listen to your conversation, at least noone is saving or tracking what you're clicking or typing.

More importantly, because radio can send data, it can be used where the internet won't go (far at least). Two things that come to mind are video links for remote controlled planes or do it yourself space exploration and many other projects I haven't thought of at this moment.

Yes.

For those that think that Amateur radio uses
acient technology, look into the great space
stuff hams are doing..

Two way satellite contacts, contacts with the
space station, hand-held data transmission
via satellite.. pretty neat stuff..

check out AMSAT and the ISS radio page.

Here ya go

www.amsat.org

It could happen. The AO-7 Satellite, launched in 1974 was "dead" for over 20 years when someone heard it by chance one day. And that satellite was built by amateurs.
More info here.
Of course, even if Pioneer "comes back", it's still travelling away from us and the signal might be far too weak to detect. It's also possible that it's operating fine, we just can't hear it anymore.. Isn't it the fastest moving object man has ever created? I admittedly not an expert on the matter.

Not sure if this is what you meant but try http://www.amsat.org/ .

The technology to develop satellites and launchers comes from and is heavily subsidized by the "defense" industry. Everyone who pays taxes in the USA is paying for those satellites.

Unless you count these guys, and microsatellites are old hat to them.

Bruce

Now I am just waiting for the HOW-TO on a Linux-run micro-satellite!

Amateur satellites are nothing new. Hams and AMSAT have been putting satellites up since the early 60's. Right now they have about 20 operational satellites in orbit. Linux based software is quite popular in the Ham community, and plays a big role in AMSAT operations. Satellite Software

The HOW-TO's :

Davidoff, Martin, The Satellite Experimenter's
Handbook Newington, CT: The American
Radio Relay League, 1984.

Jansson, Richard, Spacecraft Technology Trends
in the Amateur Satellite Service, Ogden, UT:
Proceedings of the 1st Annual USU Conference
on Small Satellites, 1987.

If NASA's budget is hurting so badly, why not swallow a bit of pride and recruit help from fans of the space program who may also happen to be hardware and software engineers?

Perhaps the crew at, say, ham radio organizations like AMSAT, or other groups that already combine volunteer engineering effort with an interest in space exploration, would be happy to help out with modernizing the systems. I wonder if anyone's asked them?

NASA would, of course, keep enough engineering staff around to check the improvements out, but why limit themselves to paid labor if the resource to pay is drying up?

The article says Despite Air Force hopes that the Atlas 5 would slash space travel costs, its debut takes place during a prolonged slump in commercial satellite launches. A glut of other new-generation rockets completed or in the works, along with a weak satellite launch market in the coming years, could mean fewer Atlases are built to recoup development costs, according to commercial aerospace officials.

There are also other national AMSAT organizations in countries around the world.

Ian Kluft KO6YQ
San Jose, California

There are also other national AMSAT organizations in countries around the world.

Ian Kluft KO6YQ
San Jose, California

There are also other national AMSAT organizations in countries around the world.

Ian Kluft KO6YQ
San Jose, California

There are also other national AMSAT organizations in countries around the world.

Ian Kluft KO6YQ
San Jose, California

There are a series of amateur radio satellites in orbit sponsored by members of The Radio Amateur Satellite Corporation and other organizations worldwide. They are free to use worldwide by anyone holding an amateur radio license. Most of these satellites are in low earth orbit, which means that they may make several passes a day. It does not take much to get started. You can communicate with other radio amateurs through these satellites with nothing more than a handheld antenna pointed at the sky and a handheld radio clipped to your belt. I use this antenna.

Yes, I know that I can whip out my cellphone and talk to anyone with much less effort. But I am a geek and this is much cooler (and fun!)

If you are in the U.S. check out the American Radio Relay League's web site for more information on getting licensed. If you are outside the U.S., check the above web site for information on getting licensed in your country. It's easy!

Beacons:

• 29.502 MHz (200 mw) Used in conjunction with Mode A

• 145.972 MHz (200 mw) Used in conjunction with Mode B and C [low power Mode B]

• 435.100 MHz (intermittent problem -- switches between 400 mw and 10 mw)

• 2304.1 MHz (40 mw) Must be commanded on. Auto off after 15 minutes. Requires STA to operate.

• Transponder I: Mode A

  • Type: linear, non-inverting

  • Uplink: 145.850 - 145.950 MHz

  • Downlink: 29.400 - 29.500 MHz

  • Translation Equation:
    Downlink (MHz) = Uplink (MHz) - 116.450 MHz +/- Doppler

  • Output Power: 1.3 watts PEP (start of life)
    

• Transponder II: Mode B and Mode C (low power)

  • Type: linear, inverting

  • Uplink: 432.125 - 432.175 MHz *See Note

  • Downlink: 145.975 - 145.925 MHz

  • Translation Equation:
    Downlink (MHz) = 578.100 - uplink (MHz) +/- Doppler

  • Output Power: 8 watts PEP Mode B (start of life), 2.5 watts PEP Mode C

*Note: Due to changes in Amateur Service and Amateur Satellite Service there are questions as to legality of Amateurs transmitting to AO-7. The uplink frequency predates the WARC '79 allocation of 435-438 MHz by the ITU for the Amateur Satellite Service and places the uplink in 70cm weak signal segment.

Potential users should realize that when they are uplinking to a satellite, they are no longer operating in the Amateur Service but instead operating in the Amateur Satellite Service. Thus they are subject to Amateur Satellite Service rules. Therefore uplinking to AO-7 is possibly illegal since the Amateur Satellite Service is not permitted at 432.1 MHz. Also, since the IARU bandplan has the 432.1 MHz range earmarked as "weak signal" in all three Regions, it would appear that all users trying to access the uplink are also outside the Amateur Satellite Service rules and regulations.

• Satellite-to-satellite relay communication via AO-6.
• Early demonstrations of low-budget medical data relay and Doppler location of ground transmitters for search-and-rescue operations were done using this satellite.
• The Mode-B transponder was the first using "HELAPS" (High Efficient Linear Amplification by Parametric Synthesis) technology was developed by Dr. Karl Meinzer as part of his Ph.D.
• First to fly a Battery Charge Regulator (BCR).

• The latest information is available from:
  • AMSAT News Service (ANS) Weekly Satellite Report (WSR)
• Jan King, W3GEY reports AO-7 is almost certainly running only off the solar panels. It is very likely to be on only when in the sun and off in eclipse. Therefore, AO-7 will reset each orbit and may not turn on each time.

Telemetry:

• AMSAT-OSCAR 7 Telemetry web page
• Thanks to Jim White, WD0E, and Jan King, W3GEY, a spreadsheet for interpreting telemetry from AO-7 has been made available in the AMSAT-NA software collection:
  • http://www.amsat.org/amsat/ftp/software/spreadshee t/AO7tlmSS.zip
  • ftp://ftp.amsat.org/amsat/software/spreadsheet
• Please forward AO-7 Telemetry to Jim White, WD0E.

Similar to AO-6. Built by a multi-national (German, Canadian, United States, and Australian) team of radio amateurs under the direction of AMSAT-NA. It carried Mode A (145.850-950 MHz uplink and 29.400-500 MHz downlink) and Mode B (432.180-120 MHz uplink and 145.920-980 MHz downlink (inverted)) linear transponders and 29.500 and 145.700 MHz beacons. The 2304.1 MHz was never turned on because of international treaty constraints.

Four radio masts mounted at 90 degree intervals on the base and two experimental repeater systems provided store-and-forward for morse and teletype messages (Codestore) as it orbited around the world. The Mode-B transponder was designed and build by Karl Meinzer, DJ4ZC and Werner Haas, DJ5KQ. The Mode-B transponder was the first using "HELAPS" (High Efficient Linear Amplification by Parametric Synthesis) technology was developed by Dr. Karl Meinzer as part of his Ph.D.

Additional information about AO-7 was printed in the September 1974 AMSAT Newsletter.

AO-7 was operational for 6.5 years until a battery failure ceased operation in mid 1981. Then on June 21, 2002, Pat Gowen, G3IOR, posted this email message on AMSAT-BB:

From: "pat gowen" <patgowen@btconnect.com>
To: <amsat-bb@AMSAT.Org>
Subject: [amsat-bb] Re: Lazarus?
Date: Fri, 21 Jun 2002 22:30:54 +0100

I have just come across something most remarkable this Friday 21st June evening. Checking out interlopers in our 145.800 - 146.000 MHz space band with a new vertical now atop my 60' tower and working like magic, at 1728 UTC I came across a beacon at S.7 sending slow 8 -10 wpm CW on 145.973.8 MHz. It slowly Dopplered down to 145.970 MHz before going out at 1739 UTC. A full run of TLM went: -

Hi Hi
100 176 164 178
280 262 200 254
375 358 331 354
453 454 461 459
541 501 552 529
600 600 601 651
Hi Hi

It sounded VERY familiar, but, I'm dammned if I can recall which one it was. Obviously an OSCAR, but which had the callsign W3OHI? Oscar-6, 7 or 8? I think it was OSCAR-6. If so, we have a new longevity record, even beating RS-1!

The beacon peaked S9 and there were S7 burbles some 10 - 20 KHz below the beacon, FSK'ing slightly as the beacon keyed. At times the beacon took on a rough quality, wobbling in frequency, then coming back strong and quite stable again. Going by the QSB rate it had about a 1 minute spin.

Could any veteran keen observers (who might look for it) please tell me what it was, as I feel sure that any old time AMSAT OSCAR devotee may have a far better memory than I!

73, Pat, G3IOR

Jan King, W3GEY, the AMSAT-OSCAR-7 Project Manager commented:

[AO-7] has a good set of arrays and the first BCR (battery charge regulator) we ever flew. It's the first spacecraft we ever had that was capable of overcharging the battery. When the battery failed the cells began to fail short. One cell after another failed and the voltage measured on telemetry began to drop. So, the cells were clearly failing SHORT. Now, after all these years, what happens if any one of the cells loses the short and becomes open? Then, the entire power bus becomes unclamped from ground and the spacecraft loads begin to again be powered but, this time only from the arrays. Now you have a daytime only satellite but, each time the sun rises at the spacecraft you have a random generator that either turns on Mode A or Mode B or whatever it wants. So, occasionally that 70cm/2m transponder transmitter and beacon must least work. From what you have told me (and without going back and decoding the old telemetry equations) I can tell you that the following things work in that spacecraft: The arrays, the BCR, the ISR (instrumentation switching regulator), the Mode B transmitter and beacon injection circuitry, the Morse Code telemetry encoder, and the voltage reference circuitry. The latter I know is working because the last telemetry value is 651. The "6" is just the row number of the telemetry value but the 51 means that the 1/2 volt reference is measuring 0.51 volts. I know that telemetry equation by heart since it was used as the calibration value for the rest of the telemetry system. So the telemetry has a fair chance of being decoded and making some sense!!! .

The full text of W3GEY's comments are here.

Initial reports on the health of AO-7 are:

• Telemetry received may be good or bad. You can determine if the telemetry is good by the 6D value. It is the reference voltage for the analog TLM system and it should be around 50. If not, then the remainder of the telemetry will be incorrect.
• Jan King, W3GEY notes that AO-7 had (has?) a very sensitive receiver and a good uplink antenna. 5 watts EIRP should provide a good downlink. Amplifiers are not required for the uplink.
• Excessive uplink power may be cause FMing of the transponder and may be causing the input voltage to the regulator that provides 6D to fluctuate causing all telemetry to be bad.
• AO-7 is almost certainly running only off the solar panels. It is very likely to be on only when in the sun and off in eclipse. Since it is resetting each orbit it may not come on every time. Reports of hearing the beacon just as it comes out of eclipse would be particularly interesting.

References

• Joe Kasser G3ZCZ/W3 and Jan King W3GEY, "OSCAR 7 and Its Capabilities," QST, Feb 1974, p. 56-60.
• "OSCAR News: OSCAR 7", QST, Nov 1974, p. 81.
• David Sumner, K1ZND, "OSCAR News: OSCAR 7 - It Works!," QST, Jan 1975, p. 49.
• "OSCAR News: Reading the OSCAR 7 Telemetry", QST, Feb 1975, p. 63.
• Perry Klein and Ray Soifer, W2RS, "Intersatellite Communication Using the AMSAT-OSCAR 6 and AMSAT-OSCAR 7 Radio Amateur Satellites," Proceedings of the IEEE Letters, Oct 1975, pp 1526-1527.
• D. Brandel, P. Schmidt, and B. Trudell, "Improvements in Search and Rescue Distress Alerting and Location Using Satellites," IEEE WESCON, Sep 1976.
• J. Kleinman, "OSCAR Medical Data," QST, Oct 1976, pp 42-43.
• D. Nelson, "Medical Relay by Satellite," Ham Radio, Apr 1977, pp 67-73.
• Martin Davidoff, "Predicting Close Encounters: OSCAR 7 and OSCAR 8," Ham Radio, Vol. 12, No. 7, Jul 1979, pp 62-67.
• "Technical Correspondence: A Look at OSCAR-7 Telemetry", QST, Jul 1980, p. 38.

• AMSAT News Service (ANS) Weekly Satellite Report (WSR)

Return to Satellite Summary

Credits: Thanks G3IOR, WD0E, W3GEY, DB2OS, W3IWI.

Last update June 23, 2002 - N7HPR

Beacons:

• 29.502 MHz (200 mw) Used in conjunction with Mode A

• 145.972 MHz (200 mw) Used in conjunction with Mode B and C [low power Mode B]

• 435.100 MHz (intermittent problem -- switches between 400 mw and 10 mw)

• 2304.1 MHz (40 mw) Must be commanded on. Auto off after 15 minutes. Requires STA to operate.

• Transponder I: Mode A

  • Type: linear, non-inverting

  • Uplink: 145.850 - 145.950 MHz

  • Downlink: 29.400 - 29.500 MHz

  • Translation Equation:
    Downlink (MHz) = Uplink (MHz) - 116.450 MHz +/- Doppler

  • Output Power: 1.3 watts PEP (start of life)
    

• Transponder II: Mode B and Mode C (low power)

  • Type: linear, inverting

  • Uplink: 432.125 - 432.175 MHz *See Note

  • Downlink: 145.975 - 145.925 MHz

  • Translation Equation:
    Downlink (MHz) = 578.100 - uplink (MHz) +/- Doppler

  • Output Power: 8 watts PEP Mode B (start of life), 2.5 watts PEP Mode C

*Note: Due to changes in Amateur Service and Amateur Satellite Service there are questions as to legality of Amateurs transmitting to AO-7. The uplink frequency predates the WARC '79 allocation of 435-438 MHz by the ITU for the Amateur Satellite Service and places the uplink in 70cm weak signal segment.

Potential users should realize that when they are uplinking to a satellite, they are no longer operating in the Amateur Service but instead operating in the Amateur Satellite Service. Thus they are subject to Amateur Satellite Service rules. Therefore uplinking to AO-7 is possibly illegal since the Amateur Satellite Service is not permitted at 432.1 MHz. Also, since the IARU bandplan has the 432.1 MHz range earmarked as "weak signal" in all three Regions, it would appear that all users trying to access the uplink are also outside the Amateur Satellite Service rules and regulations.

• Satellite-to-satellite relay communication via AO-6.
• Early demonstrations of low-budget medical data relay and Doppler location of ground transmitters for search-and-rescue operations were done using this satellite.
• The Mode-B transponder was the first using "HELAPS" (High Efficient Linear Amplification by Parametric Synthesis) technology was developed by Dr. Karl Meinzer as part of his Ph.D.
• First to fly a Battery Charge Regulator (BCR).

• The latest information is available from:
  • AMSAT News Service (ANS) Weekly Satellite Report (WSR)
• Jan King, W3GEY reports AO-7 is almost certainly running only off the solar panels. It is very likely to be on only when in the sun and off in eclipse. Therefore, AO-7 will reset each orbit and may not turn on each time.

Telemetry:

• AMSAT-OSCAR 7 Telemetry web page
• Thanks to Jim White, WD0E, and Jan King, W3GEY, a spreadsheet for interpreting telemetry from AO-7 has been made available in the AMSAT-NA software collection:
  • http://www.amsat.org/amsat/ftp/software/spreadshee t/AO7tlmSS.zip
  • ftp://ftp.amsat.org/amsat/software/spreadsheet
• Please forward AO-7 Telemetry to Jim White, WD0E.

Similar to AO-6. Built by a multi-national (German, Canadian, United States, and Australian) team of radio amateurs under the direction of AMSAT-NA. It carried Mode A (145.850-950 MHz uplink and 29.400-500 MHz downlink) and Mode B (432.180-120 MHz uplink and 145.920-980 MHz downlink (inverted)) linear transponders and 29.500 and 145.700 MHz beacons. The 2304.1 MHz was never turned on because of international treaty constraints.

Four radio masts mounted at 90 degree intervals on the base and two experimental repeater systems provided store-and-forward for morse and teletype messages (Codestore) as it orbited around the world. The Mode-B transponder was designed and build by Karl Meinzer, DJ4ZC and Werner Haas, DJ5KQ. The Mode-B transponder was the first using "HELAPS" (High Efficient Linear Amplification by Parametric Synthesis) technology was developed by Dr. Karl Meinzer as part of his Ph.D.

Additional information about AO-7 was printed in the September 1974 AMSAT Newsletter.

AO-7 was operational for 6.5 years until a battery failure ceased operation in mid 1981. Then on June 21, 2002, Pat Gowen, G3IOR, posted this email message on AMSAT-BB:

From: "pat gowen" <patgowen@btconnect.com>
To: <amsat-bb@AMSAT.Org>
Subject: [amsat-bb] Re: Lazarus?
Date: Fri, 21 Jun 2002 22:30:54 +0100

I have just come across something most remarkable this Friday 21st June evening. Checking out interlopers in our 145.800 - 146.000 MHz space band with a new vertical now atop my 60' tower and working like magic, at 1728 UTC I came across a beacon at S.7 sending slow 8 -10 wpm CW on 145.973.8 MHz. It slowly Dopplered down to 145.970 MHz before going out at 1739 UTC. A full run of TLM went: -

Hi Hi
100 176 164 178
280 262 200 254
375 358 331 354
453 454 461 459
541 501 552 529
600 600 601 651
Hi Hi

It sounded VERY familiar, but, I'm dammned if I can recall which one it was. Obviously an OSCAR, but which had the callsign W3OHI? Oscar-6, 7 or 8? I think it was OSCAR-6. If so, we have a new longevity record, even beating RS-1!

The beacon peaked S9 and there were S7 burbles some 10 - 20 KHz below the beacon, FSK'ing slightly as the beacon keyed. At times the beacon took on a rough quality, wobbling in frequency, then coming back strong and quite stable again. Going by the QSB rate it had about a 1 minute spin.

Could any veteran keen observers (who might look for it) please tell me what it was, as I feel sure that any old time AMSAT OSCAR devotee may have a far better memory than I!

73, Pat, G3IOR

Jan King, W3GEY, the AMSAT-OSCAR-7 Project Manager commented:

[AO-7] has a good set of arrays and the first BCR (battery charge regulator) we ever flew. It's the first spacecraft we ever had that was capable of overcharging the battery. When the battery failed the cells began to fail short. One cell after another failed and the voltage measured on telemetry began to drop. So, the cells were clearly failing SHORT. Now, after all these years, what happens if any one of the cells loses the short and becomes open? Then, the entire power bus becomes unclamped from ground and the spacecraft loads begin to again be powered but, this time only from the arrays. Now you have a daytime only satellite but, each time the sun rises at the spacecraft you have a random generator that either turns on Mode A or Mode B or whatever it wants. So, occasionally that 70cm/2m transponder transmitter and beacon must least work. From what you have told me (and without going back and decoding the old telemetry equations) I can tell you that the following things work in that spacecraft: The arrays, the BCR, the ISR (instrumentation switching regulator), the Mode B transmitter and beacon injection circuitry, the Morse Code telemetry encoder, and the voltage reference circuitry. The latter I know is working because the last telemetry value is 651. The "6" is just the row number of the telemetry value but the 51 means that the 1/2 volt reference is measuring 0.51 volts. I know that telemetry equation by heart since it was used as the calibration value for the rest of the telemetry system. So the telemetry has a fair chance of being decoded and making some sense!!! .

The full text of W3GEY's comments are here.

Initial reports on the health of AO-7 are:

• Telemetry received may be good or bad. You can determine if the telemetry is good by the 6D value. It is the reference voltage for the analog TLM system and it should be around 50. If not, then the remainder of the telemetry will be incorrect.
• Jan King, W3GEY notes that AO-7 had (has?) a very sensitive receiver and a good uplink antenna. 5 watts EIRP should provide a good downlink. Amplifiers are not required for the uplink.
• Excessive uplink power may be cause FMing of the transponder and may be causing the input voltage to the regulator that provides 6D to fluctuate causing all telemetry to be bad.
• AO-7 is almost certainly running only off the solar panels. It is very likely to be on only when in the sun and off in eclipse. Since it is resetting each orbit it may not come on every time. Reports of hearing the beacon just as it comes out of eclipse would be particularly interesting.

References

• Joe Kasser G3ZCZ/W3 and Jan King W3GEY, "OSCAR 7 and Its Capabilities," QST, Feb 1974, p. 56-60.
• "OSCAR News: OSCAR 7", QST, Nov 1974, p. 81.
• David Sumner, K1ZND, "OSCAR News: OSCAR 7 - It Works!," QST, Jan 1975, p. 49.
• "OSCAR News: Reading the OSCAR 7 Telemetry", QST, Feb 1975, p. 63.
• Perry Klein and Ray Soifer, W2RS, "Intersatellite Communication Using the AMSAT-OSCAR 6 and AMSAT-OSCAR 7 Radio Amateur Satellites," Proceedings of the IEEE Letters, Oct 1975, pp 1526-1527.
• D. Brandel, P. Schmidt, and B. Trudell, "Improvements in Search and Rescue Distress Alerting and Location Using Satellites," IEEE WESCON, Sep 1976.
• J. Kleinman, "OSCAR Medical Data," QST, Oct 1976, pp 42-43.
• D. Nelson, "Medical Relay by Satellite," Ham Radio, Apr 1977, pp 67-73.
• Martin Davidoff, "Predicting Close Encounters: OSCAR 7 and OSCAR 8," Ham Radio, Vol. 12, No. 7, Jul 1979, pp 62-67.
• "Technical Correspondence: A Look at OSCAR-7 Telemetry", QST, Jul 1980, p. 38.

• AMSAT News Service (ANS) Weekly Satellite Report (WSR)

Return to Satellite Summary

Credits: Thanks G3IOR, WD0E, W3GEY, DB2OS, W3IWI.

Last update June 23, 2002 - N7HPR

Beacons:

• 29.502 MHz (200 mw) Used in conjunction with Mode A

• 145.972 MHz (200 mw) Used in conjunction with Mode B and C [low power Mode B]

• 435.100 MHz (intermittent problem -- switches between 400 mw and 10 mw)

• 2304.1 MHz (40 mw) Must be commanded on. Auto off after 15 minutes. Requires STA to operate.

• Transponder I: Mode A

  • Type: linear, non-inverting

  • Uplink: 145.850 - 145.950 MHz

  • Downlink: 29.400 - 29.500 MHz

  • Translation Equation:
    Downlink (MHz) = Uplink (MHz) - 116.450 MHz +/- Doppler

  • Output Power: 1.3 watts PEP (start of life)
    

• Transponder II: Mode B and Mode C (low power)

  • Type: linear, inverting

  • Uplink: 432.125 - 432.175 MHz *See Note

  • Downlink: 145.975 - 145.925 MHz

  • Translation Equation:
    Downlink (MHz) = 578.100 - uplink (MHz) +/- Doppler

  • Output Power: 8 watts PEP Mode B (start of life), 2.5 watts PEP Mode C

*Note: Due to changes in Amateur Service and Amateur Satellite Service there are questions as to legality of Amateurs transmitting to AO-7. The uplink frequency predates the WARC '79 allocation of 435-438 MHz by the ITU for the Amateur Satellite Service and places the uplink in 70cm weak signal segment.

Potential users should realize that when they are uplinking to a satellite, they are no longer operating in the Amateur Service but instead operating in the Amateur Satellite Service. Thus they are subject to Amateur Satellite Service rules. Therefore uplinking to AO-7 is possibly illegal since the Amateur Satellite Service is not permitted at 432.1 MHz. Also, since the IARU bandplan has the 432.1 MHz range earmarked as "weak signal" in all three Regions, it would appear that all users trying to access the uplink are also outside the Amateur Satellite Service rules and regulations.

• Satellite-to-satellite relay communication via AO-6.
• Early demonstrations of low-budget medical data relay and Doppler location of ground transmitters for search-and-rescue operations were done using this satellite.
• The Mode-B transponder was the first using "HELAPS" (High Efficient Linear Amplification by Parametric Synthesis) technology was developed by Dr. Karl Meinzer as part of his Ph.D.
• First to fly a Battery Charge Regulator (BCR).

• The latest information is available from:
  • AMSAT News Service (ANS) Weekly Satellite Report (WSR)
• Jan King, W3GEY reports AO-7 is almost certainly running only off the solar panels. It is very likely to be on only when in the sun and off in eclipse. Therefore, AO-7 will reset each orbit and may not turn on each time.

Telemetry:

• AMSAT-OSCAR 7 Telemetry web page
• Thanks to Jim White, WD0E, and Jan King, W3GEY, a spreadsheet for interpreting telemetry from AO-7 has been made available in the AMSAT-NA software collection:
  • http://www.amsat.org/amsat/ftp/software/spreadshee t/AO7tlmSS.zip
  • ftp://ftp.amsat.org/amsat/software/spreadsheet
• Please forward AO-7 Telemetry to Jim White, WD0E.

Similar to AO-6. Built by a multi-national (German, Canadian, United States, and Australian) team of radio amateurs under the direction of AMSAT-NA. It carried Mode A (145.850-950 MHz uplink and 29.400-500 MHz downlink) and Mode B (432.180-120 MHz uplink and 145.920-980 MHz downlink (inverted)) linear transponders and 29.500 and 145.700 MHz beacons. The 2304.1 MHz was never turned on because of international treaty constraints.

Four radio masts mounted at 90 degree intervals on the base and two experimental repeater systems provided store-and-forward for morse and teletype messages (Codestore) as it orbited around the world. The Mode-B transponder was designed and build by Karl Meinzer, DJ4ZC and Werner Haas, DJ5KQ. The Mode-B transponder was the first using "HELAPS" (High Efficient Linear Amplification by Parametric Synthesis) technology was developed by Dr. Karl Meinzer as part of his Ph.D.

Additional information about AO-7 was printed in the September 1974 AMSAT Newsletter.

AO-7 was operational for 6.5 years until a battery failure ceased operation in mid 1981. Then on June 21, 2002, Pat Gowen, G3IOR, posted this email message on AMSAT-BB:

From: "pat gowen" <patgowen@btconnect.com>
To: <amsat-bb@AMSAT.Org>
Subject: [amsat-bb] Re: Lazarus?
Date: Fri, 21 Jun 2002 22:30:54 +0100

I have just come across something most remarkable this Friday 21st June evening. Checking out interlopers in our 145.800 - 146.000 MHz space band with a new vertical now atop my 60' tower and working like magic, at 1728 UTC I came across a beacon at S.7 sending slow 8 -10 wpm CW on 145.973.8 MHz. It slowly Dopplered down to 145.970 MHz before going out at 1739 UTC. A full run of TLM went: -

Hi Hi
100 176 164 178
280 262 200 254
375 358 331 354
453 454 461 459
541 501 552 529
600 600 601 651
Hi Hi

It sounded VERY familiar, but, I'm dammned if I can recall which one it was. Obviously an OSCAR, but which had the callsign W3OHI? Oscar-6, 7 or 8? I think it was OSCAR-6. If so, we have a new longevity record, even beating RS-1!

The beacon peaked S9 and there were S7 burbles some 10 - 20 KHz below the beacon, FSK'ing slightly as the beacon keyed. At times the beacon took on a rough quality, wobbling in frequency, then coming back strong and quite stable again. Going by the QSB rate it had about a 1 minute spin.

Could any veteran keen observers (who might look for it) please tell me what it was, as I feel sure that any old time AMSAT OSCAR devotee may have a far better memory than I!

73, Pat, G3IOR

Jan King, W3GEY, the AMSAT-OSCAR-7 Project Manager commented:

[AO-7] has a good set of arrays and the first BCR (battery charge regulator) we ever flew. It's the first spacecraft we ever had that was capable of overcharging the battery. When the battery failed the cells began to fail short. One cell after another failed and the voltage measured on telemetry began to drop. So, the cells were clearly failing SHORT. Now, after all these years, what happens if any one of the cells loses the short and becomes open? Then, the entire power bus becomes unclamped from ground and the spacecraft loads begin to again be powered but, this time only from the arrays. Now you have a daytime only satellite but, each time the sun rises at the spacecraft you have a random generator that either turns on Mode A or Mode B or whatever it wants. So, occasionally that 70cm/2m transponder transmitter and beacon must least work. From what you have told me (and without going back and decoding the old telemetry equations) I can tell you that the following things work in that spacecraft: The arrays, the BCR, the ISR (instrumentation switching regulator), the Mode B transmitter and beacon injection circuitry, the Morse Code telemetry encoder, and the voltage reference circuitry. The latter I know is working because the last telemetry value is 651. The "6" is just the row number of the telemetry value but the 51 means that the 1/2 volt reference is measuring 0.51 volts. I know that telemetry equation by heart since it was used as the calibration value for the rest of the telemetry system. So the telemetry has a fair chance of being decoded and making some sense!!! .

The full text of W3GEY's comments are here.

Initial reports on the health of AO-7 are:

• Telemetry received may be good or bad. You can determine if the telemetry is good by the 6D value. It is the reference voltage for the analog TLM system and it should be around 50. If not, then the remainder of the telemetry will be incorrect.
• Jan King, W3GEY notes that AO-7 had (has?) a very sensitive receiver and a good uplink antenna. 5 watts EIRP should provide a good downlink. Amplifiers are not required for the uplink.
• Excessive uplink power may be cause FMing of the transponder and may be causing the input voltage to the regulator that provides 6D to fluctuate causing all telemetry to be bad.
• AO-7 is almost certainly running only off the solar panels. It is very likely to be on only when in the sun and off in eclipse. Since it is resetting each orbit it may not come on every time. Reports of hearing the beacon just as it comes out of eclipse would be particularly interesting.

References

• Joe Kasser G3ZCZ/W3 and Jan King W3GEY, "OSCAR 7 and Its Capabilities," QST, Feb 1974, p. 56-60.
• "OSCAR News: OSCAR 7", QST, Nov 1974, p. 81.
• David Sumner, K1ZND, "OSCAR News: OSCAR 7 - It Works!," QST, Jan 1975, p. 49.
• "OSCAR News: Reading the OSCAR 7 Telemetry", QST, Feb 1975, p. 63.
• Perry Klein and Ray Soifer, W2RS, "Intersatellite Communication Using the AMSAT-OSCAR 6 and AMSAT-OSCAR 7 Radio Amateur Satellites," Proceedings of the IEEE Letters, Oct 1975, pp 1526-1527.
• D. Brandel, P. Schmidt, and B. Trudell, "Improvements in Search and Rescue Distress Alerting and Location Using Satellites," IEEE WESCON, Sep 1976.
• J. Kleinman, "OSCAR Medical Data," QST, Oct 1976, pp 42-43.
• D. Nelson, "Medical Relay by Satellite," Ham Radio, Apr 1977, pp 67-73.
• Martin Davidoff, "Predicting Close Encounters: OSCAR 7 and OSCAR 8," Ham Radio, Vol. 12, No. 7, Jul 1979, pp 62-67.
• "Technical Correspondence: A Look at OSCAR-7 Telemetry", QST, Jul 1980, p. 38.

• AMSAT News Service (ANS) Weekly Satellite Report (WSR)

Return to Satellite Summary

Credits: Thanks G3IOR, WD0E, W3GEY, DB2OS, W3IWI.

Last update June 23, 2002 - N7HPR

Beacons:

• 29.502 MHz (200 mw) Used in conjunction with Mode A

• 145.972 MHz (200 mw) Used in conjunction with Mode B and C [low power Mode B]

• 435.100 MHz (intermittent problem -- switches between 400 mw and 10 mw)

• 2304.1 MHz (40 mw) Must be commanded on. Auto off after 15 minutes. Requires STA to operate.

• Transponder I: Mode A

  • Type: linear, non-inverting

  • Uplink: 145.850 - 145.950 MHz

  • Downlink: 29.400 - 29.500 MHz

  • Translation Equation:
    Downlink (MHz) = Uplink (MHz) - 116.450 MHz +/- Doppler

  • Output Power: 1.3 watts PEP (start of life)
    

• Transponder II: Mode B and Mode C (low power)

  • Type: linear, inverting

  • Uplink: 432.125 - 432.175 MHz *See Note

  • Downlink: 145.975 - 145.925 MHz

  • Translation Equation:
    Downlink (MHz) = 578.100 - uplink (MHz) +/- Doppler

  • Output Power: 8 watts PEP Mode B (start of life), 2.5 watts PEP Mode C

*Note: Due to changes in Amateur Service and Amateur Satellite Service there are questions as to legality of Amateurs transmitting to AO-7. The uplink frequency predates the WARC '79 allocation of 435-438 MHz by the ITU for the Amateur Satellite Service and places the uplink in 70cm weak signal segment.

Potential users should realize that when they are uplinking to a satellite, they are no longer operating in the Amateur Service but instead operating in the Amateur Satellite Service. Thus they are subject to Amateur Satellite Service rules. Therefore uplinking to AO-7 is possibly illegal since the Amateur Satellite Service is not permitted at 432.1 MHz. Also, since the IARU bandplan has the 432.1 MHz range earmarked as "weak signal" in all three Regions, it would appear that all users trying to access the uplink are also outside the Amateur Satellite Service rules and regulations.

• Satellite-to-satellite relay communication via AO-6.
• Early demonstrations of low-budget medical data relay and Doppler location of ground transmitters for search-and-rescue operations were done using this satellite.
• The Mode-B transponder was the first using "HELAPS" (High Efficient Linear Amplification by Parametric Synthesis) technology was developed by Dr. Karl Meinzer as part of his Ph.D.
• First to fly a Battery Charge Regulator (BCR).

• The latest information is available from:
  • AMSAT News Service (ANS) Weekly Satellite Report (WSR)
• Jan King, W3GEY reports AO-7 is almost certainly running only off the solar panels. It is very likely to be on only when in the sun and off in eclipse. Therefore, AO-7 will reset each orbit and may not turn on each time.

Telemetry:

• AMSAT-OSCAR 7 Telemetry web page
• Thanks to Jim White, WD0E, and Jan King, W3GEY, a spreadsheet for interpreting telemetry from AO-7 has been made available in the AMSAT-NA software collection:
  • http://www.amsat.org/amsat/ftp/software/spreadshee t/AO7tlmSS.zip
  • ftp://ftp.amsat.org/amsat/software/spreadsheet
• Please forward AO-7 Telemetry to Jim White, WD0E.

Similar to AO-6. Built by a multi-national (German, Canadian, United States, and Australian) team of radio amateurs under the direction of AMSAT-NA. It carried Mode A (145.850-950 MHz uplink and 29.400-500 MHz downlink) and Mode B (432.180-120 MHz uplink and 145.920-980 MHz downlink (inverted)) linear transponders and 29.500 and 145.700 MHz beacons. The 2304.1 MHz was never turned on because of international treaty constraints.

Four radio masts mounted at 90 degree intervals on the base and two experimental repeater systems provided store-and-forward for morse and teletype messages (Codestore) as it orbited around the world. The Mode-B transponder was designed and build by Karl Meinzer, DJ4ZC and Werner Haas, DJ5KQ. The Mode-B transponder was the first using "HELAPS" (High Efficient Linear Amplification by Parametric Synthesis) technology was developed by Dr. Karl Meinzer as part of his Ph.D.

Additional information about AO-7 was printed in the September 1974 AMSAT Newsletter.

AO-7 was operational for 6.5 years until a battery failure ceased operation in mid 1981. Then on June 21, 2002, Pat Gowen, G3IOR, posted this email message on AMSAT-BB:

From: "pat gowen" <patgowen@btconnect.com>
To: <amsat-bb@AMSAT.Org>
Subject: [amsat-bb] Re: Lazarus?
Date: Fri, 21 Jun 2002 22:30:54 +0100

I have just come across something most remarkable this Friday 21st June evening. Checking out interlopers in our 145.800 - 146.000 MHz space band with a new vertical now atop my 60' tower and working like magic, at 1728 UTC I came across a beacon at S.7 sending slow 8 -10 wpm CW on 145.973.8 MHz. It slowly Dopplered down to 145.970 MHz before going out at 1739 UTC. A full run of TLM went: -

Hi Hi
100 176 164 178
280 262 200 254
375 358 331 354
453 454 461 459
541 501 552 529
600 600 601 651
Hi Hi

It sounded VERY familiar, but, I'm dammned if I can recall which one it was. Obviously an OSCAR, but which had the callsign W3OHI? Oscar-6, 7 or 8? I think it was OSCAR-6. If so, we have a new longevity record, even beating RS-1!

The beacon peaked S9 and there were S7 burbles some 10 - 20 KHz below the beacon, FSK'ing slightly as the beacon keyed. At times the beacon took on a rough quality, wobbling in frequency, then coming back strong and quite stable again. Going by the QSB rate it had about a 1 minute spin.

Could any veteran keen observers (who might look for it) please tell me what it was, as I feel sure that any old time AMSAT OSCAR devotee may have a far better memory than I!

73, Pat, G3IOR

Jan King, W3GEY, the AMSAT-OSCAR-7 Project Manager commented:

[AO-7] has a good set of arrays and the first BCR (battery charge regulator) we ever flew. It's the first spacecraft we ever had that was capable of overcharging the battery. When the battery failed the cells began to fail short. One cell after another failed and the voltage measured on telemetry began to drop. So, the cells were clearly failing SHORT. Now, after all these years, what happens if any one of the cells loses the short and becomes open? Then, the entire power bus becomes unclamped from ground and the spacecraft loads begin to again be powered but, this time only from the arrays. Now you have a daytime only satellite but, each time the sun rises at the spacecraft you have a random generator that either turns on Mode A or Mode B or whatever it wants. So, occasionally that 70cm/2m transponder transmitter and beacon must least work. From what you have told me (and without going back and decoding the old telemetry equations) I can tell you that the following things work in that spacecraft: The arrays, the BCR, the ISR (instrumentation switching regulator), the Mode B transmitter and beacon injection circuitry, the Morse Code telemetry encoder, and the voltage reference circuitry. The latter I know is working because the last telemetry value is 651. The "6" is just the row number of the telemetry value but the 51 means that the 1/2 volt reference is measuring 0.51 volts. I know that telemetry equation by heart since it was used as the calibration value for the rest of the telemetry system. So the telemetry has a fair chance of being decoded and making some sense!!! .

The full text of W3GEY's comments are here.

Initial reports on the health of AO-7 are:

• Telemetry received may be good or bad. You can determine if the telemetry is good by the 6D value. It is the reference voltage for the analog TLM system and it should be around 50. If not, then the remainder of the telemetry will be incorrect.
• Jan King, W3GEY notes that AO-7 had (has?) a very sensitive receiver and a good uplink antenna. 5 watts EIRP should provide a good downlink. Amplifiers are not required for the uplink.
• Excessive uplink power may be cause FMing of the transponder and may be causing the input voltage to the regulator that provides 6D to fluctuate causing all telemetry to be bad.
• AO-7 is almost certainly running only off the solar panels. It is very likely to be on only when in the sun and off in eclipse. Since it is resetting each orbit it may not come on every time. Reports of hearing the beacon just as it comes out of eclipse would be particularly interesting.

References

• Joe Kasser G3ZCZ/W3 and Jan King W3GEY, "OSCAR 7 and Its Capabilities," QST, Feb 1974, p. 56-60.
• "OSCAR News: OSCAR 7", QST, Nov 1974, p. 81.
• David Sumner, K1ZND, "OSCAR News: OSCAR 7 - It Works!," QST, Jan 1975, p. 49.
• "OSCAR News: Reading the OSCAR 7 Telemetry", QST, Feb 1975, p. 63.
• Perry Klein and Ray Soifer, W2RS, "Intersatellite Communication Using the AMSAT-OSCAR 6 and AMSAT-OSCAR 7 Radio Amateur Satellites," Proceedings of the IEEE Letters, Oct 1975, pp 1526-1527.
• D. Brandel, P. Schmidt, and B. Trudell, "Improvements in Search and Rescue Distress Alerting and Location Using Satellites," IEEE WESCON, Sep 1976.
• J. Kleinman, "OSCAR Medical Data," QST, Oct 1976, pp 42-43.
• D. Nelson, "Medical Relay by Satellite," Ham Radio, Apr 1977, pp 67-73.
• Martin Davidoff, "Predicting Close Encounters: OSCAR 7 and OSCAR 8," Ham Radio, Vol. 12, No. 7, Jul 1979, pp 62-67.
• "Technical Correspondence: A Look at OSCAR-7 Telemetry", QST, Jul 1980, p. 38.

• AMSAT News Service (ANS) Weekly Satellite Report (WSR)

Return to Satellite Summary

Credits: Thanks G3IOR, WD0E, W3GEY, DB2OS, W3IWI.

Last update June 23, 2002 - N7HPR

Beacons:

• 29.502 MHz (200 mw) Used in conjunction with Mode A

• 145.972 MHz (200 mw) Used in conjunction with Mode B and C [low power Mode B]

• 435.100 MHz (intermittent problem -- switches between 400 mw and 10 mw)

• 2304.1 MHz (40 mw) Must be commanded on. Auto off after 15 minutes. Requires STA to operate.

• Transponder I: Mode A

  • Type: linear, non-inverting

  • Uplink: 145.850 - 145.950 MHz

  • Downlink: 29.400 - 29.500 MHz

  • Translation Equation:
    Downlink (MHz) = Uplink (MHz) - 116.450 MHz +/- Doppler

  • Output Power: 1.3 watts PEP (start of life)
    

• Transponder II: Mode B and Mode C (low power)

  • Type: linear, inverting

  • Uplink: 432.125 - 432.175 MHz *See Note

  • Downlink: 145.975 - 145.925 MHz

  • Translation Equation:
    Downlink (MHz) = 578.100 - uplink (MHz) +/- Doppler

  • Output Power: 8 watts PEP Mode B (start of life), 2.5 watts PEP Mode C

*Note: Due to changes in Amateur Service and Amateur Satellite Service there are questions as to legality of Amateurs transmitting to AO-7. The uplink frequency predates the WARC '79 allocation of 435-438 MHz by the ITU for the Amateur Satellite Service and places the uplink in 70cm weak signal segment.

Potential users should realize that when they are uplinking to a satellite, they are no longer operating in the Amateur Service but instead operating in the Amateur Satellite Service. Thus they are subject to Amateur Satellite Service rules. Therefore uplinking to AO-7 is possibly illegal since the Amateur Satellite Service is not permitted at 432.1 MHz. Also, since the IARU bandplan has the 432.1 MHz range earmarked as "weak signal" in all three Regions, it would appear that all users trying to access the uplink are also outside the Amateur Satellite Service rules and regulations.

• Satellite-to-satellite relay communication via AO-6.
• Early demonstrations of low-budget medical data relay and Doppler location of ground transmitters for search-and-rescue operations were done using this satellite.
• The Mode-B transponder was the first using "HELAPS" (High Efficient Linear Amplification by Parametric Synthesis) technology was developed by Dr. Karl Meinzer as part of his Ph.D.
• First to fly a Battery Charge Regulator (BCR).

• The latest information is available from:
  • AMSAT News Service (ANS) Weekly Satellite Report (WSR)
• Jan King, W3GEY reports AO-7 is almost certainly running only off the solar panels. It is very likely to be on only when in the sun and off in eclipse. Therefore, AO-7 will reset each orbit and may not turn on each time.

Telemetry:

• AMSAT-OSCAR 7 Telemetry web page
• Thanks to Jim White, WD0E, and Jan King, W3GEY, a spreadsheet for interpreting telemetry from AO-7 has been made available in the AMSAT-NA software collection:
  • http://www.amsat.org/amsat/ftp/software/spreadshee t/AO7tlmSS.zip
  • ftp://ftp.amsat.org/amsat/software/spreadsheet
• Please forward AO-7 Telemetry to Jim White, WD0E.

Similar to AO-6. Built by a multi-national (German, Canadian, United States, and Australian) team of radio amateurs under the direction of AMSAT-NA. It carried Mode A (145.850-950 MHz uplink and 29.400-500 MHz downlink) and Mode B (432.180-120 MHz uplink and 145.920-980 MHz downlink (inverted)) linear transponders and 29.500 and 145.700 MHz beacons. The 2304.1 MHz was never turned on because of international treaty constraints.

Four radio masts mounted at 90 degree intervals on the base and two experimental repeater systems provided store-and-forward for morse and teletype messages (Codestore) as it orbited around the world. The Mode-B transponder was designed and build by Karl Meinzer, DJ4ZC and Werner Haas, DJ5KQ. The Mode-B transponder was the first using "HELAPS" (High Efficient Linear Amplification by Parametric Synthesis) technology was developed by Dr. Karl Meinzer as part of his Ph.D.

Additional information about AO-7 was printed in the September 1974 AMSAT Newsletter.

AO-7 was operational for 6.5 years until a battery failure ceased operation in mid 1981. Then on June 21, 2002, Pat Gowen, G3IOR, posted this email message on AMSAT-BB:

From: "pat gowen" <patgowen@btconnect.com>
To: <amsat-bb@AMSAT.Org>
Subject: [amsat-bb] Re: Lazarus?
Date: Fri, 21 Jun 2002 22:30:54 +0100

I have just come across something most remarkable this Friday 21st June evening. Checking out interlopers in our 145.800 - 146.000 MHz space band with a new vertical now atop my 60' tower and working like magic, at 1728 UTC I came across a beacon at S.7 sending slow 8 -10 wpm CW on 145.973.8 MHz. It slowly Dopplered down to 145.970 MHz before going out at 1739 UTC. A full run of TLM went: -

Hi Hi
100 176 164 178
280 262 200 254
375 358 331 354
453 454 461 459
541 501 552 529
600 600 601 651
Hi Hi

It sounded VERY familiar, but, I'm dammned if I can recall which one it was. Obviously an OSCAR, but which had the callsign W3OHI? Oscar-6, 7 or 8? I think it was OSCAR-6. If so, we have a new longevity record, even beating RS-1!

The beacon peaked S9 and there were S7 burbles some 10 - 20 KHz below the beacon, FSK'ing slightly as the beacon keyed. At times the beacon took on a rough quality, wobbling in frequency, then coming back strong and quite stable again. Going by the QSB rate it had about a 1 minute spin.

Could any veteran keen observers (who might look for it) please tell me what it was, as I feel sure that any old time AMSAT OSCAR devotee may have a far better memory than I!

73, Pat, G3IOR

Jan King, W3GEY, the AMSAT-OSCAR-7 Project Manager commented:

[AO-7] has a good set of arrays and the first BCR (battery charge regulator) we ever flew. It's the first spacecraft we ever had that was capable of overcharging the battery. When the battery failed the cells began to fail short. One cell after another failed and the voltage measured on telemetry began to drop. So, the cells were clearly failing SHORT. Now, after all these years, what happens if any one of the cells loses the short and becomes open? Then, the entire power bus becomes unclamped from ground and the spacecraft loads begin to again be powered but, this time only from the arrays. Now you have a daytime only satellite but, each time the sun rises at the spacecraft you have a random generator that either turns on Mode A or Mode B or whatever it wants. So, occasionally that 70cm/2m transponder transmitter and beacon must least work. From what you have told me (and without going back and decoding the old telemetry equations) I can tell you that the following things work in that spacecraft: The arrays, the BCR, the ISR (instrumentation switching regulator), the Mode B transmitter and beacon injection circuitry, the Morse Code telemetry encoder, and the voltage reference circuitry. The latter I know is working because the last telemetry value is 651. The "6" is just the row number of the telemetry value but the 51 means that the 1/2 volt reference is measuring 0.51 volts. I know that telemetry equation by heart since it was used as the calibration value for the rest of the telemetry system. So the telemetry has a fair chance of being decoded and making some sense!!! .

The full text of W3GEY's comments are here.

Initial reports on the health of AO-7 are:

• Telemetry received may be good or bad. You can determine if the telemetry is good by the 6D value. It is the reference voltage for the analog TLM system and it should be around 50. If not, then the remainder of the telemetry will be incorrect.
• Jan King, W3GEY notes that AO-7 had (has?) a very sensitive receiver and a good uplink antenna. 5 watts EIRP should provide a good downlink. Amplifiers are not required for the uplink.
• Excessive uplink power may be cause FMing of the transponder and may be causing the input voltage to the regulator that provides 6D to fluctuate causing all telemetry to be bad.
• AO-7 is almost certainly running only off the solar panels. It is very likely to be on only when in the sun and off in eclipse. Since it is resetting each orbit it may not come on every time. Reports of hearing the beacon just as it comes out of eclipse would be particularly interesting.

References

• Joe Kasser G3ZCZ/W3 and Jan King W3GEY, "OSCAR 7 and Its Capabilities," QST, Feb 1974, p. 56-60.
• "OSCAR News: OSCAR 7", QST, Nov 1974, p. 81.
• David Sumner, K1ZND, "OSCAR News: OSCAR 7 - It Works!," QST, Jan 1975, p. 49.
• "OSCAR News: Reading the OSCAR 7 Telemetry", QST, Feb 1975, p. 63.
• Perry Klein and Ray Soifer, W2RS, "Intersatellite Communication Using the AMSAT-OSCAR 6 and AMSAT-OSCAR 7 Radio Amateur Satellites," Proceedings of the IEEE Letters, Oct 1975, pp 1526-1527.
• D. Brandel, P. Schmidt, and B. Trudell, "Improvements in Search and Rescue Distress Alerting and Location Using Satellites," IEEE WESCON, Sep 1976.
• J. Kleinman, "OSCAR Medical Data," QST, Oct 1976, pp 42-43.
• D. Nelson, "Medical Relay by Satellite," Ham Radio, Apr 1977, pp 67-73.
• Martin Davidoff, "Predicting Close Encounters: OSCAR 7 and OSCAR 8," Ham Radio, Vol. 12, No. 7, Jul 1979, pp 62-67.
• "Technical Correspondence: A Look at OSCAR-7 Telemetry", QST, Jul 1980, p. 38.

• AMSAT News Service (ANS) Weekly Satellite Report (WSR)

Return to Satellite Summary

Credits: Thanks G3IOR, WD0E, W3GEY, DB2OS, W3IWI.

Last update June 23, 2002 - N7HPR

Beacons:

• 29.502 MHz (200 mw) Used in conjunction with Mode A

• 145.972 MHz (200 mw) Used in conjunction with Mode B and C [low power Mode B]

• 435.100 MHz (intermittent problem -- switches between 400 mw and 10 mw)

• 2304.1 MHz (40 mw) Must be commanded on. Auto off after 15 minutes. Requires STA to operate.

• Transponder I: Mode A

  • Type: linear, non-inverting

  • Uplink: 145.850 - 145.950 MHz

  • Downlink: 29.400 - 29.500 MHz

  • Translation Equation:
    Downlink (MHz) = Uplink (MHz) - 116.450 MHz +/- Doppler

  • Output Power: 1.3 watts PEP (start of life)
    

• Transponder II: Mode B and Mode C (low power)

  • Type: linear, inverting

  • Uplink: 432.125 - 432.175 MHz *See Note

  • Downlink: 145.975 - 145.925 MHz

  • Translation Equation:
    Downlink (MHz) = 578.100 - uplink (MHz) +/- Doppler

  • Output Power: 8 watts PEP Mode B (start of life), 2.5 watts PEP Mode C

*Note: Due to changes in Amateur Service and Amateur Satellite Service there are questions as to legality of Amateurs transmitting to AO-7. The uplink frequency predates the WARC '79 allocation of 435-438 MHz by the ITU for the Amateur Satellite Service and places the uplink in 70cm weak signal segment.

Potential users should realize that when they are uplinking to a satellite, they are no longer operating in the Amateur Service but instead operating in the Amateur Satellite Service. Thus they are subject to Amateur Satellite Service rules. Therefore uplinking to AO-7 is possibly illegal since the Amateur Satellite Service is not permitted at 432.1 MHz. Also, since the IARU bandplan has the 432.1 MHz range earmarked as "weak signal" in all three Regions, it would appear that all users trying to access the uplink are also outside the Amateur Satellite Service rules and regulations.

• Satellite-to-satellite relay communication via AO-6.
• Early demonstrations of low-budget medical data relay and Doppler location of ground transmitters for search-and-rescue operations were done using this satellite.
• The Mode-B transponder was the first using "HELAPS" (High Efficient Linear Amplification by Parametric Synthesis) technology was developed by Dr. Karl Meinzer as part of his Ph.D.
• First to fly a Battery Charge Regulator (BCR).

• The latest information is available from:
  • AMSAT News Service (ANS) Weekly Satellite Report (WSR)
• Jan King, W3GEY reports AO-7 is almost certainly running only off the solar panels. It is very likely to be on only when in the sun and off in eclipse. Therefore, AO-7 will reset each orbit and may not turn on each time.

Telemetry:

• AMSAT-OSCAR 7 Telemetry web page
• Thanks to Jim White, WD0E, and Jan King, W3GEY, a spreadsheet for interpreting telemetry from AO-7 has been made available in the AMSAT-NA software collection:
  • http://www.amsat.org/amsat/ftp/software/spreadshee t/AO7tlmSS.zip
  • ftp://ftp.amsat.org/amsat/software/spreadsheet
• Please forward AO-7 Telemetry to Jim White, WD0E.

Similar to AO-6. Built by a multi-national (German, Canadian, United States, and Australian) team of radio amateurs under the direction of AMSAT-NA. It carried Mode A (145.850-950 MHz uplink and 29.400-500 MHz downlink) and Mode B (432.180-120 MHz uplink and 145.920-980 MHz downlink (inverted)) linear transponders and 29.500 and 145.700 MHz beacons. The 2304.1 MHz was never turned on because of international treaty constraints.

Four radio masts mounted at 90 degree intervals on the base and two experimental repeater systems provided store-and-forward for morse and teletype messages (Codestore) as it orbited around the world. The Mode-B transponder was designed and build by Karl Meinzer, DJ4ZC and Werner Haas, DJ5KQ. The Mode-B transponder was the first using "HELAPS" (High Efficient Linear Amplification by Parametric Synthesis) technology was developed by Dr. Karl Meinzer as part of his Ph.D.

Additional information about AO-7 was printed in the September 1974 AMSAT Newsletter.

AO-7 was operational for 6.5 years until a battery failure ceased operation in mid 1981. Then on June 21, 2002, Pat Gowen, G3IOR, posted this email message on AMSAT-BB:

From: "pat gowen" <patgowen@btconnect.com>
To: <amsat-bb@AMSAT.Org>
Subject: [amsat-bb] Re: Lazarus?
Date: Fri, 21 Jun 2002 22:30:54 +0100

I have just come across something most remarkable this Friday 21st June evening. Checking out interlopers in our 145.800 - 146.000 MHz space band with a new vertical now atop my 60' tower and working like magic, at 1728 UTC I came across a beacon at S.7 sending slow 8 -10 wpm CW on 145.973.8 MHz. It slowly Dopplered down to 145.970 MHz before going out at 1739 UTC. A full run of TLM went: -

Hi Hi
100 176 164 178
280 262 200 254
375 358 331 354
453 454 461 459
541 501 552 529
600 600 601 651
Hi Hi

It sounded VERY familiar, but, I'm dammned if I can recall which one it was. Obviously an OSCAR, but which had the callsign W3OHI? Oscar-6, 7 or 8? I think it was OSCAR-6. If so, we have a new longevity record, even beating RS-1!

The beacon peaked S9 and there were S7 burbles some 10 - 20 KHz below the beacon, FSK'ing slightly as the beacon keyed. At times the beacon took on a rough quality, wobbling in frequency, then coming back strong and quite stable again. Going by the QSB rate it had about a 1 minute spin.

Could any veteran keen observers (who might look for it) please tell me what it was, as I feel sure that any old time AMSAT OSCAR devotee may have a far better memory than I!

73, Pat, G3IOR

Jan King, W3GEY, the AMSAT-OSCAR-7 Project Manager commented:

[AO-7] has a good set of arrays and the first BCR (battery charge regulator) we ever flew. It's the first spacecraft we ever had that was capable of overcharging the battery. When the battery failed the cells began to fail short. One cell after another failed and the voltage measured on telemetry began to drop. So, the cells were clearly failing SHORT. Now, after all these years, what happens if any one of the cells loses the short and becomes open? Then, the entire power bus becomes unclamped from ground and the spacecraft loads begin to again be powered but, this time only from the arrays. Now you have a daytime only satellite but, each time the sun rises at the spacecraft you have a random generator that either turns on Mode A or Mode B or whatever it wants. So, occasionally that 70cm/2m transponder transmitter and beacon must least work. From what you have told me (and without going back and decoding the old telemetry equations) I can tell you that the following things work in that spacecraft: The arrays, the BCR, the ISR (instrumentation switching regulator), the Mode B transmitter and beacon injection circuitry, the Morse Code telemetry encoder, and the voltage reference circuitry. The latter I know is working because the last telemetry value is 651. The "6" is just the row number of the telemetry value but the 51 means that the 1/2 volt reference is measuring 0.51 volts. I know that telemetry equation by heart since it was used as the calibration value for the rest of the telemetry system. So the telemetry has a fair chance of being decoded and making some sense!!! .

The full text of W3GEY's comments are here.

Initial reports on the health of AO-7 are:

• Telemetry received may be good or bad. You can determine if the telemetry is good by the 6D value. It is the reference voltage for the analog TLM system and it should be around 50. If not, then the remainder of the telemetry will be incorrect.
• Jan King, W3GEY notes that AO-7 had (has?) a very sensitive receiver and a good uplink antenna. 5 watts EIRP should provide a good downlink. Amplifiers are not required for the uplink.
• Excessive uplink power may be cause FMing of the transponder and may be causing the input voltage to the regulator that provides 6D to fluctuate causing all telemetry to be bad.
• AO-7 is almost certainly running only off the solar panels. It is very likely to be on only when in the sun and off in eclipse. Since it is resetting each orbit it may not come on every time. Reports of hearing the beacon just as it comes out of eclipse would be particularly interesting.

References

• Joe Kasser G3ZCZ/W3 and Jan King W3GEY, "OSCAR 7 and Its Capabilities," QST, Feb 1974, p. 56-60.
• "OSCAR News: OSCAR 7", QST, Nov 1974, p. 81.
• David Sumner, K1ZND, "OSCAR News: OSCAR 7 - It Works!," QST, Jan 1975, p. 49.
• "OSCAR News: Reading the OSCAR 7 Telemetry", QST, Feb 1975, p. 63.
• Perry Klein and Ray Soifer, W2RS, "Intersatellite Communication Using the AMSAT-OSCAR 6 and AMSAT-OSCAR 7 Radio Amateur Satellites," Proceedings of the IEEE Letters, Oct 1975, pp 1526-1527.
• D. Brandel, P. Schmidt, and B. Trudell, "Improvements in Search and Rescue Distress Alerting and Location Using Satellites," IEEE WESCON, Sep 1976.
• J. Kleinman, "OSCAR Medical Data," QST, Oct 1976, pp 42-43.
• D. Nelson, "Medical Relay by Satellite," Ham Radio, Apr 1977, pp 67-73.
• Martin Davidoff, "Predicting Close Encounters: OSCAR 7 and OSCAR 8," Ham Radio, Vol. 12, No. 7, Jul 1979, pp 62-67.
• "Technical Correspondence: A Look at OSCAR-7 Telemetry", QST, Jul 1980, p. 38.

• AMSAT News Service (ANS) Weekly Satellite Report (WSR)

Return to Satellite Summary

Credits: Thanks G3IOR, WD0E, W3GEY, DB2OS, W3IWI.

Last update June 23, 2002 - N7HPR

Beacons:

• 29.502 MHz (200 mw) Used in conjunction with Mode A

• 145.972 MHz (200 mw) Used in conjunction with Mode B and C [low power Mode B]

• 435.100 MHz (intermittent problem -- switches between 400 mw and 10 mw)

• 2304.1 MHz (40 mw) Must be commanded on. Auto off after 15 minutes. Requires STA to operate.

• Transponder I: Mode A

  • Type: linear, non-inverting

  • Uplink: 145.850 - 145.950 MHz

  • Downlink: 29.400 - 29.500 MHz

  • Translation Equation:
    Downlink (MHz) = Uplink (MHz) - 116.450 MHz +/- Doppler

  • Output Power: 1.3 watts PEP (start of life)
    

• Transponder II: Mode B and Mode C (low power)

  • Type: linear, inverting

  • Uplink: 432.125 - 432.175 MHz *See Note

  • Downlink: 145.975 - 145.925 MHz

  • Translation Equation:
    Downlink (MHz) = 578.100 - uplink (MHz) +/- Doppler

  • Output Power: 8 watts PEP Mode B (start of life), 2.5 watts PEP Mode C

*Note: Due to changes in Amateur Service and Amateur Satellite Service there are questions as to legality of Amateurs transmitting to AO-7. The uplink frequency predates the WARC '79 allocation of 435-438 MHz by the ITU for the Amateur Satellite Service and places the uplink in 70cm weak signal segment.

Potential users should realize that when they are uplinking to a satellite, they are no longer operating in the Amateur Service but instead operating in the Amateur Satellite Service. Thus they are subject to Amateur Satellite Service rules. Therefore uplinking to AO-7 is possibly illegal since the Amateur Satellite Service is not permitted at 432.1 MHz. Also, since the IARU bandplan has the 432.1 MHz range earmarked as "weak signal" in all three Regions, it would appear that all users trying to access the uplink are also outside the Amateur Satellite Service rules and regulations.

• Satellite-to-satellite relay communication via AO-6.
• Early demonstrations of low-budget medical data relay and Doppler location of ground transmitters for search-and-rescue operations were done using this satellite.
• The Mode-B transponder was the first using "HELAPS" (High Efficient Linear Amplification by Parametric Synthesis) technology was developed by Dr. Karl Meinzer as part of his Ph.D.
• First to fly a Battery Charge Regulator (BCR).

• The latest information is available from:
  • AMSAT News Service (ANS) Weekly Satellite Report (WSR)
• Jan King, W3GEY reports AO-7 is almost certainly running only off the solar panels. It is very likely to be on only when in the sun and off in eclipse. Therefore, AO-7 will reset each orbit and may not turn on each time.

Telemetry:

• AMSAT-OSCAR 7 Telemetry web page
• Thanks to Jim White, WD0E, and Jan King, W3GEY, a spreadsheet for interpreting telemetry from AO-7 has been made available in the AMSAT-NA software collection:
  • http://www.amsat.org/amsat/ftp/software/spreadshee t/AO7tlmSS.zip
  • ftp://ftp.amsat.org/amsat/software/spreadsheet
• Please forward AO-7 Telemetry to Jim White, WD0E.

Similar to AO-6. Built by a multi-national (German, Canadian, United States, and Australian) team of radio amateurs under the direction of AMSAT-NA. It carried Mode A (145.850-950 MHz uplink and 29.400-500 MHz downlink) and Mode B (432.180-120 MHz uplink and 145.920-980 MHz downlink (inverted)) linear transponders and 29.500 and 145.700 MHz beacons. The 2304.1 MHz was never turned on because of international treaty constraints.

Four radio masts mounted at 90 degree intervals on the base and two experimental repeater systems provided store-and-forward for morse and teletype messages (Codestore) as it orbited around the world. The Mode-B transponder was designed and build by Karl Meinzer, DJ4ZC and Werner Haas, DJ5KQ. The Mode-B transponder was the first using "HELAPS" (High Efficient Linear Amplification by Parametric Synthesis) technology was developed by Dr. Karl Meinzer as part of his Ph.D.

Additional information about AO-7 was printed in the September 1974 AMSAT Newsletter.

AO-7 was operational for 6.5 years until a battery failure ceased operation in mid 1981. Then on June 21, 2002, Pat Gowen, G3IOR, posted this email message on AMSAT-BB:

From: "pat gowen" <patgowen@btconnect.com>
To: <amsat-bb@AMSAT.Org>
Subject: [amsat-bb] Re: Lazarus?
Date: Fri, 21 Jun 2002 22:30:54 +0100

I have just come across something most remarkable this Friday 21st June evening. Checking out interlopers in our 145.800 - 146.000 MHz space band with a new vertical now atop my 60' tower and working like magic, at 1728 UTC I came across a beacon at S.7 sending slow 8 -10 wpm CW on 145.973.8 MHz. It slowly Dopplered down to 145.970 MHz before going out at 1739 UTC. A full run of TLM went: -

Hi Hi
100 176 164 178
280 262 200 254
375 358 331 354
453 454 461 459
541 501 552 529
600 600 601 651
Hi Hi

It sounded VERY familiar, but, I'm dammned if I can recall which one it was. Obviously an OSCAR, but which had the callsign W3OHI? Oscar-6, 7 or 8? I think it was OSCAR-6. If so, we have a new longevity record, even beating RS-1!

The beacon peaked S9 and there were S7 burbles some 10 - 20 KHz below the beacon, FSK'ing slightly as the beacon keyed. At times the beacon took on a rough quality, wobbling in frequency, then coming back strong and quite stable again. Going by the QSB rate it had about a 1 minute spin.

Could any veteran keen observers (who might look for it) please tell me what it was, as I feel sure that any old time AMSAT OSCAR devotee may have a far better memory than I!

73, Pat, G3IOR

Jan King, W3GEY, the AMSAT-OSCAR-7 Project Manager commented:

[AO-7] has a good set of arrays and the first BCR (battery charge regulator) we ever flew. It's the first spacecraft we ever had that was capable of overcharging the battery. When the battery failed the cells began to fail short. One cell after another failed and the voltage measured on telemetry began to drop. So, the cells were clearly failing SHORT. Now, after all these years, what happens if any one of the cells loses the short and becomes open? Then, the entire power bus becomes unclamped from ground and the spacecraft loads begin to again be powered but, this time only from the arrays. Now you have a daytime only satellite but, each time the sun rises at the spacecraft you have a random generator that either turns on Mode A or Mode B or whatever it wants. So, occasionally that 70cm/2m transponder transmitter and beacon must least work. From what you have told me (and without going back and decoding the old telemetry equations) I can tell you that the following things work in that spacecraft: The arrays, the BCR, the ISR (instrumentation switching regulator), the Mode B transmitter and beacon injection circuitry, the Morse Code telemetry encoder, and the voltage reference circuitry. The latter I know is working because the last telemetry value is 651. The "6" is just the row number of the telemetry value but the 51 means that the 1/2 volt reference is measuring 0.51 volts. I know that telemetry equation by heart since it was used as the calibration value for the rest of the telemetry system. So the telemetry has a fair chance of being decoded and making some sense!!! .

The full text of W3GEY's comments are here.

Initial reports on the health of AO-7 are:

• Telemetry received may be good or bad. You can determine if the telemetry is good by the 6D value. It is the reference voltage for the analog TLM system and it should be around 50. If not, then the remainder of the telemetry will be incorrect.
• Jan King, W3GEY notes that AO-7 had (has?) a very sensitive receiver and a good uplink antenna. 5 watts EIRP should provide a good downlink. Amplifiers are not required for the uplink.
• Excessive uplink power may be cause FMing of the transponder and may be causing the input voltage to the regulator that provides 6D to fluctuate causing all telemetry to be bad.
• AO-7 is almost certainly running only off the solar panels. It is very likely to be on only when in the sun and off in eclipse. Since it is resetting each orbit it may not come on every time. Reports of hearing the beacon just as it comes out of eclipse would be particularly interesting.

References

• Joe Kasser G3ZCZ/W3 and Jan King W3GEY, "OSCAR 7 and Its Capabilities," QST, Feb 1974, p. 56-60.
• "OSCAR News: OSCAR 7", QST, Nov 1974, p. 81.
• David Sumner, K1ZND, "OSCAR News: OSCAR 7 - It Works!," QST, Jan 1975, p. 49.
• "OSCAR News: Reading the OSCAR 7 Telemetry", QST, Feb 1975, p. 63.
• Perry Klein and Ray Soifer, W2RS, "Intersatellite Communication Using the AMSAT-OSCAR 6 and AMSAT-OSCAR 7 Radio Amateur Satellites," Proceedings of the IEEE Letters, Oct 1975, pp 1526-1527.
• D. Brandel, P. Schmidt, and B. Trudell, "Improvements in Search and Rescue Distress Alerting and Location Using Satellites," IEEE WESCON, Sep 1976.
• J. Kleinman, "OSCAR Medical Data," QST, Oct 1976, pp 42-43.
• D. Nelson, "Medical Relay by Satellite," Ham Radio, Apr 1977, pp 67-73.
• Martin Davidoff, "Predicting Close Encounters: OSCAR 7 and OSCAR 8," Ham Radio, Vol. 12, No. 7, Jul 1979, pp 62-67.
• "Technical Correspondence: A Look at OSCAR-7 Telemetry", QST, Jul 1980, p. 38.

• AMSAT News Service (ANS) Weekly Satellite Report (WSR)

Return to Satellite Summary

Credits: Thanks G3IOR, WD0E, W3GEY, DB2OS, W3IWI.

Last update June 23, 2002 - N7HPR

Beacons:

• 29.502 MHz (200 mw) Used in conjunction with Mode A

• 145.972 MHz (200 mw) Used in conjunction with Mode B and C [low power Mode B]

• 435.100 MHz (intermittent problem -- switches between 400 mw and 10 mw)

• 2304.1 MHz (40 mw) Must be commanded on. Auto off after 15 minutes. Requires STA to operate.

• Transponder I: Mode A

  • Type: linear, non-inverting

  • Uplink: 145.850 - 145.950 MHz

  • Downlink: 29.400 - 29.500 MHz

  • Translation Equation:
    Downlink (MHz) = Uplink (MHz) - 116.450 MHz +/- Doppler

  • Output Power: 1.3 watts PEP (start of life)
    

• Transponder II: Mode B and Mode C (low power)

  • Type: linear, inverting

  • Uplink: 432.125 - 432.175 MHz *See Note

  • Downlink: 145.975 - 145.925 MHz

  • Translation Equation:
    Downlink (MHz) = 578.100 - uplink (MHz) +/- Doppler

  • Output Power: 8 watts PEP Mode B (start of life), 2.5 watts PEP Mode C

*Note: Due to changes in Amateur Service and Amateur Satellite Service there are questions as to legality of Amateurs transmitting to AO-7. The uplink frequency predates the WARC '79 allocation of 435-438 MHz by the ITU for the Amateur Satellite Service and places the uplink in 70cm weak signal segment.

Potential users should realize that when they are uplinking to a satellite, they are no longer operating in the Amateur Service but instead operating in the Amateur Satellite Service. Thus they are subject to Amateur Satellite Service rules. Therefore uplinking to AO-7 is possibly illegal since the Amateur Satellite Service is not permitted at 432.1 MHz. Also, since the IARU bandplan has the 432.1 MHz range earmarked as "weak signal" in all three Regions, it would appear that all users trying to access the uplink are also outside the Amateur Satellite Service rules and regulations.

• Satellite-to-satellite relay communication via AO-6.
• Early demonstrations of low-budget medical data relay and Doppler location of ground transmitters for search-and-rescue operations were done using this satellite.
• The Mode-B transponder was the first using "HELAPS" (High Efficient Linear Amplification by Parametric Synthesis) technology was developed by Dr. Karl Meinzer as part of his Ph.D.
• First to fly a Battery Charge Regulator (BCR).

• The latest information is available from:
  • AMSAT News Service (ANS) Weekly Satellite Report (WSR)
• Jan King, W3GEY reports AO-7 is almost certainly running only off the solar panels. It is very likely to be on only when in the sun and off in eclipse. Therefore, AO-7 will reset each orbit and may not turn on each time.

Telemetry:

• AMSAT-OSCAR 7 Telemetry web page
• Thanks to Jim White, WD0E, and Jan King, W3GEY, a spreadsheet for interpreting telemetry from AO-7 has been made available in the AMSAT-NA software collection:
  • http://www.amsat.org/amsat/ftp/software/spreadshee t/AO7tlmSS.zip
  • ftp://ftp.amsat.org/amsat/software/spreadsheet
• Please forward AO-7 Telemetry to Jim White, WD0E.

Similar to AO-6. Built by a multi-national (German, Canadian, United States, and Australian) team of radio amateurs under the direction of AMSAT-NA. It carried Mode A (145.850-950 MHz uplink and 29.400-500 MHz downlink) and Mode B (432.180-120 MHz uplink and 145.920-980 MHz downlink (inverted)) linear transponders and 29.500 and 145.700 MHz beacons. The 2304.1 MHz was never turned on because of international treaty constraints.

Four radio masts mounted at 90 degree intervals on the base and two experimental repeater systems provided store-and-forward for morse and teletype messages (Codestore) as it orbited around the world. The Mode-B transponder was designed and build by Karl Meinzer, DJ4ZC and Werner Haas, DJ5KQ. The Mode-B transponder was the first using "HELAPS" (High Efficient Linear Amplification by Parametric Synthesis) technology was developed by Dr. Karl Meinzer as part of his Ph.D.

Additional information about AO-7 was printed in the September 1974 AMSAT Newsletter.

AO-7 was operational for 6.5 years until a battery failure ceased operation in mid 1981. Then on June 21, 2002, Pat Gowen, G3IOR, posted this email message on AMSAT-BB:

From: "pat gowen" <patgowen@btconnect.com>
To: <amsat-bb@AMSAT.Org>
Subject: [amsat-bb] Re: Lazarus?
Date: Fri, 21 Jun 2002 22:30:54 +0100

I have just come across something most remarkable this Friday 21st June evening. Checking out interlopers in our 145.800 - 146.000 MHz space band with a new vertical now atop my 60' tower and working like magic, at 1728 UTC I came across a beacon at S.7 sending slow 8 -10 wpm CW on 145.973.8 MHz. It slowly Dopplered down to 145.970 MHz before going out at 1739 UTC. A full run of TLM went: -

Hi Hi
100 176 164 178
280 262 200 254
375 358 331 354
453 454 461 459
541 501 552 529
600 600 601 651
Hi Hi

It sounded VERY familiar, but, I'm dammned if I can recall which one it was. Obviously an OSCAR, but which had the callsign W3OHI? Oscar-6, 7 or 8? I think it was OSCAR-6. If so, we have a new longevity record, even beating RS-1!

The beacon peaked S9 and there were S7 burbles some 10 - 20 KHz below the beacon, FSK'ing slightly as the beacon keyed. At times the beacon took on a rough quality, wobbling in frequency, then coming back strong and quite stable again. Going by the QSB rate it had about a 1 minute spin.

Could any veteran keen observers (who might look for it) please tell me what it was, as I feel sure that any old time AMSAT OSCAR devotee may have a far better memory than I!

73, Pat, G3IOR

Jan King, W3GEY, the AMSAT-OSCAR-7 Project Manager commented:

[AO-7] has a good set of arrays and the first BCR (battery charge regulator) we ever flew. It's the first spacecraft we ever had that was capable of overcharging the battery. When the battery failed the cells began to fail short. One cell after another failed and the voltage measured on telemetry began to drop. So, the cells were clearly failing SHORT. Now, after all these years, what happens if any one of the cells loses the short and becomes open? Then, the entire power bus becomes unclamped from ground and the spacecraft loads begin to again be powered but, this time only from the arrays. Now you have a daytime only satellite but, each time the sun rises at the spacecraft you have a random generator that either turns on Mode A or Mode B or whatever it wants. So, occasionally that 70cm/2m transponder transmitter and beacon must least work. From what you have told me (and without going back and decoding the old telemetry equations) I can tell you that the following things work in that spacecraft: The arrays, the BCR, the ISR (instrumentation switching regulator), the Mode B transmitter and beacon injection circuitry, the Morse Code telemetry encoder, and the voltage reference circuitry. The latter I know is working because the last telemetry value is 651. The "6" is just the row number of the telemetry value but the 51 means that the 1/2 volt reference is measuring 0.51 volts. I know that telemetry equation by heart since it was used as the calibration value for the rest of the telemetry system. So the telemetry has a fair chance of being decoded and making some sense!!! .

The full text of W3GEY's comments are here.

Initial reports on the health of AO-7 are:

• Telemetry received may be good or bad. You can determine if the telemetry is good by the 6D value. It is the reference voltage for the analog TLM system and it should be around 50. If not, then the remainder of the telemetry will be incorrect.
• Jan King, W3GEY notes that AO-7 had (has?) a very sensitive receiver and a good uplink antenna. 5 watts EIRP should provide a good downlink. Amplifiers are not required for the uplink.
• Excessive uplink power may be cause FMing of the transponder and may be causing the input voltage to the regulator that provides 6D to fluctuate causing all telemetry to be bad.
• AO-7 is almost certainly running only off the solar panels. It is very likely to be on only when in the sun and off in eclipse. Since it is resetting each orbit it may not come on every time. Reports of hearing the beacon just as it comes out of eclipse would be particularly interesting.

References

• Joe Kasser G3ZCZ/W3 and Jan King W3GEY, "OSCAR 7 and Its Capabilities," QST, Feb 1974, p. 56-60.
• "OSCAR News: OSCAR 7", QST, Nov 1974, p. 81.
• David Sumner, K1ZND, "OSCAR News: OSCAR 7 - It Works!," QST, Jan 1975, p. 49.
• "OSCAR News: Reading the OSCAR 7 Telemetry", QST, Feb 1975, p. 63.
• Perry Klein and Ray Soifer, W2RS, "Intersatellite Communication Using the AMSAT-OSCAR 6 and AMSAT-OSCAR 7 Radio Amateur Satellites," Proceedings of the IEEE Letters, Oct 1975, pp 1526-1527.
• D. Brandel, P. Schmidt, and B. Trudell, "Improvements in Search and Rescue Distress Alerting and Location Using Satellites," IEEE WESCON, Sep 1976.
• J. Kleinman, "OSCAR Medical Data," QST, Oct 1976, pp 42-43.
• D. Nelson, "Medical Relay by Satellite," Ham Radio, Apr 1977, pp 67-73.
• Martin Davidoff, "Predicting Close Encounters: OSCAR 7 and OSCAR 8," Ham Radio, Vol. 12, No. 7, Jul 1979, pp 62-67.
• "Technical Correspondence: A Look at OSCAR-7 Telemetry", QST, Jul 1980, p. 38.

• AMSAT News Service (ANS) Weekly Satellite Report (WSR)

Return to Satellite Summary

Credits: Thanks G3IOR, WD0E, W3GEY, DB2OS, W3IWI.

Last update June 23, 2002 - N7HPR

AMSAT builds tons of other cool things, check them out...

More AO-7 status info here

Interesting to note that it is expected (and wasn't made clear in the original article) that OSCAR-7 is operating on the solar array only. Meaning that it shuts down when it's not in sunlight and may or may not reboot each sunlight period. I find that believable because I wouldn't expect a NiCd battery pack to last even half that number of years. Especially given the type of charging circuit that was probably used in those days. Nobody used the dV/dT fast/smart charge method way back when.

The newer event which you refer to, AMSAT FD, is world-wide, and lasts longer, satellite contacts only.

ARRL FD is mostly Region II (the americas). In prior years, only US and Canadian stations competed, but this year all Region II (NAM/CAM/SAM) stations may compete. Contacts with I & III count for the Region II station, if the DX gives (or can be prompted to give) a proper Exchange (1D mostly likely, if they're home on commercial power).

Many HF radio contests are worldwide in nature as you suggest. This one is not restricted to HF, but is MW-HF-VHF+, and is specifically termed an Operating Event. It is a mixture of a Contest and a wide-area Drill. It differs from a Simulated Emergency Test in not having a disaster scenario, and in having contest-rules and scoring; everyone is out in the field as if they were the affected area. We're demonstrating that we can restore communications locally and wide area from improvised positions. Other countries' national associations have their own Field Days on other weekends.

A FD station may participate in both. The first AMSAT contact with full ARRL exchange is 100 bonus points on the ARRL, and each additional is another QSO point, and doesn't count against band/transmitter limits.

73 de Bill N1VUX
I'll be operating at W1BOS VHF+ positions, and visiting other Metro-Boston sites for ARES

There is a little more to it than that. check out AMSAT for some info on one other aspect of the hobby.

'73 de
VE6LSH

Yeah - I recomened it because I am an amatuer radio operator where the legal limit is technically 1500 watts - although I think it is much lower on that band (not to mention if you plan on running 1500 watts you'll require a station inspection)

Legal limits are all governed by the bands and licenese (or lack there of) they run on.

Omni-directional antennas are more convienant but they offer less gain. If you were to go around your run of the mill omni-directional antenna with a field strength meter you might notice a nice figure 8 pattern - while with a directional antenna you'll notice a considerable amount of the radiation is reflected down what I like to call parasitic elements (elements of the antenna that direct the signal) - the advantage is just distance - you can get a clearer signal into a system with a directional antenna.

Thing is with more amatuer radio sattelites - they are somewhat hard to use with just omni-directional antennas. Take for instance AO-27 - which is a FM sattelite more info here

With omni directional equipment you'll need a pre-amp - ie something that will amplify the signal coming into your reciever and you'll need at least 25 watts (if not more) going into the uplink. Where with a directional antenna I've actually used this same sattelite with at little as 2.5 watts on the uplink and no pre-amp.

One other thing to consider is that it's not impossible to hack in or take control of satalites. The radio equipment itself is readily avalible and most satalites operate on security by obscurity. Amsat.org has artcles on ham radio satalites and the equipment amatures use to communicate with them is compatable with the comercial ones. I'd be afraid of a smart guy with a grudge against dish network might decide to get rid of everyone's satalite TV!, Or more frightening, Military Sats.

Well this satalite has been planned to come down around the 31st of january since it was launched, according to this link about the project. It doesnt state if they intentionally left the menuvering devices off, or as happens on alot of satalites, somehow malfunctioned during it's life.

To those who are commenting about a self destruct sequence, think about what kind of trouble we would be in if someone hacked all the communication satalites up there... or the military sats. satalite communication equipment is quite easily obtained or built, and current sats employ security by obscurity.

Sending a signal up to a satellite is fairly easy and somthing that ham radio operators have been doing for years. AMSAT is a good place to check out what has already been done as far as getting a signal up to an orbiting target go. Additionally some ham radio operators have opperated at what's called moonbounce or EME (earth-moon-earth) where they send a signal off the moon and back just for a bit of a challenge and the fun of it. There is also information arround on high power transmitters that are used for that. Hams have been able to do that sort of thing for years. Keep in mind though since that information is public others can do the very same thing. Also somone with a malicious intent won't likely be concerned with government communication regulations.
73 de VE6OMJ

Take a look at the history of AMSAT and Amateur Radio satellites. This whole concept (tape measure, off-the shelf components, hitch-hiking on the boosters) was done by amateur radio operators in the 60's. Many of those satellites were operational for years.

I took the exam on the 22th

you took the exam but you don't know what class of license you need for 50MHz and above? WTF?!

frequencies and status of all amateur satellites, updated weekly

a technician class license will give you all the ham bands 50MHz and up.

If all goes well, you should be able to at least hear the downlink packets with a VHF scanner and 1/4 wave vertical antenna (YMMV). You will need a AX.25 TNC and terminal or comparable sound-card software to see the telemetry from the satellite and APRS position reports that get relayed through the satellite. Note that locations in the US will have to wait about 9 orbits before they can hear anything.

More info on the PCSAT web page. You can learn more about amateur radio at the ARRL web page and about amateur satellites at the AMSAT web page.

73, KA1LM

Solar radiation is an extremely serious problem for any computer in space. To be rad-hard, chips need to be made of silicon on sapphire, which means a $1 embedded processor suddenly costs twenty thousand dollars. This is not material cost, it's because the economies of scale in production of terrestrial processors are what drives the cost down. Nobody can afford sapphire RAM banks, and thus memories get a flipped bit per orbit, in general. The only way they keep working is that there is a "washing" process that scans memory and does ECC correction continuously. Shielding is simply too heavy to be practical (send up a lead-clad satellite, and your rocket becomes 10 times as large to boost the weight).

Because it's available in sapphire and is flight-proven, the microprocessor of choice for controlling satellites is the 1802. Remember the RCA Cosmac Elf? Most of you weren't born when that was a popular hobby computer

I was surprised to find that the Phase 3D satellite boots up with no ROM. Hardware loads RAM directly from a radio modem. They couldn't afford a ROM they could trust.

Heat is a problem, too. Heat sinks don't work so well without an atmosphere to carry away heat. You have to pipe heat around with heat-pipes filled with a phase-change gas, and then radiate the heat away.Bruce

Well, I don't know about other slashdotter's, but it's the gushing "gee-whizz, isn't this wonderful" attitude of the submission. It's not like it hasn't been done before, again, again, and again.

Well, I don't know about other slashdotter's, but it's the gushing "gee-whizz, isn't this wonderful" attitude of the submission. It's not like it hasn't been done before, again, again, and again.

Well, I don't know about other slashdotter's, but it's the gushing "gee-whizz, isn't this wonderful" attitude of the submission. It's not like it hasn't been done before, again, again, and again.