Last Week's Bulletins
These Bulletins in plain text format
Subscribe to bulletins by e-mail
Submit your News for ANS
Volunteers, AO-7 and other matters.
Recently there has been much discussion on the AMSAT-BB concerning the "Role of Volunteers" in AMSAT-NA. Well let me say that AMSAT-NA is consists almost entirely of volunteers. I am a volunteer, all the Board of Directors are volunteers, and almost all of our Officers are volunteers.
However we do keep asking for more volunteers, when we don't always use the ones that reply!
Very simply we need to have a pool of volunteers who are interested and available so that when a "Situation Vacant" occurs we can get it filled quickly. This particularly applies to designers and builders, who are generally very specialized in their areas of expertise.
Currently we have a shortage of Editors for ANS - we need two more - but we have recently filled two positions very quickly. In the next few months we will probably need some satellite builder expertise - but right now we need names and background information so we can put the right people to work at the right jobs when the time arises.
Also I need some people who would like to be considered as future Presidents of AMSAT-NA, do you have a background which would enable you to lead this organization?. If so let me know. The training is good, but the pay is .... well let me say Tax free and doubles every year .. if you know what that means!.
The volunteer survey which was carried out earlier this year has enabled AMSAT to select several "assistants" and other positions, please do not be discouraged if you do not get an immediate answer to your volunteer request. However as a recent AMSAT-BB E-mail said "Keep pushing" and let us know you are there and ready to work!. The Volunteer survey is still available, see the AMSAT.org web page, about half way down on the right hand side click on "Volunteer survey" to get a copy sent to you.
The re-discovery of AO-7 has raised many questions for satellite design, particularly when it was apparent that one of the uplink frequencies is no longer in the "Satellite part of the Spectrum". Of course AMSAT-NA is not a regulatory body and it is not up to us to tell you what to do, or what not to do! that is up to your regulatory body in the country in which you transmit. Please refer to them.
However AO-7 has raised a number of technical problems for future design.
Some of which are,
a) should we be able to remove the batteries from the circuitry at the end of their life and keep the satellite operational on the solar cells only?
b) If so, with a multi-mode satellite how are we able to control the modes?
c) At the end of battery life do we close the satellite down and return it to earth?
All these questions are tied in with future possible regulations which may require that "orbital debris" be returned to earth or burnt up in the atmosphere on re-entry.
Certainly the experimentation of trying to control AO-7 using operational codes will provide us with a great deal of knowledge and data for future designs. There are those who decry the attempts to control AO-7, but let us remember that AMSAT's progress in satellite design and development has come about from experimentation and knowledge, based on previous designs. There is still a lot we can learn from AO-7 and attempts to control it.
On a similar note using the RUDAK on AO-40 has taught us a great deal. It has also provided some of AO-40 sponsors with much valuable information, and may induce them to work with us again in the future. Yes, it is very frustrating when you cannot make a certain contact through the bird, because RUDAK is on at the only possible time. But this will not always be the case, and that valuable contact will eventually be made!
I understand from Martha, that the Ballots for the Board of Directors have now been mailed. Please fill out your ballot and return it promptly. There are five candidates to fill three positions - make your ballot count. May the best candidates win!
In the same mailing is the Registration Form for the Annual Meeting and Space Symposium, to be held in Fort Worth. Of all the attributes that attracted me to AMSAT, when I first Joined, was the Space Symposium. Truly a wealth of knowledge which is made available for so little cost. Other organizations charge several hundred dollars for this type and quality of information. I strongly recommend you to attend, and meet the experts!
Also in your package is a President's Club membership form. Are you a President's club member? do you support the design, building and launching of our satellites?. Remember without satellites that satellite rig you have may eventually become far less useful!.
Join the President's Club and make sure that by your regular contributions, your satellite radio equipment remains useful. If you are already a member paying yearly then now is a good time to renew and I look forward to hearing that you are maintaining your support.
Enjoy your summer and have a great vacation
Robin Haighton VE3FRH
Many APRS operators may see DX stations as far as 2000 miles away pop up on their local APRS RF area maps every now and then. These are received from PCsat.
PCsat is currently relaying most APRS Satellite uplinks back down on both 145.825 AND 144.39. So anyone whose maps are not cluttered by all the Internet feeds, might enjoy watching for PCsat DX a few times a day on their normal terrestrial system.
Whenever PCsat resets (it does every 1.6 hours now when it goes into dark), it cross connects the transmitters. Thus anyone uplinking on the normal PCsat uplink of 145.825 will come down on BOTH unless a SYSOP commands PCsat to isolate the transmitters.
Anyone with special needs can ask for access to the unpublished uplink (contact email@example.com) to always come down on 144.39. Currently we have one user, on a railroad car that uplinks so that he comes down on 144.39. Look for N3IYI.
More information is on the PCsat WEB page, http://www.ew.usna.edu/~bruninga/pcsat.html
[ANS thanks Bob Bruninga, WB4APR, for the above information.]
Bob Bruninga WB4APR announced that PCSat has turned DIGI OFF and all 1200 baud TLM off.
Although PCsat has been perfectly usable in the afternoons into early evenings, the satellite is still running the batteries down on every eclipse. So today I thought of one last low power mode I can try so we turned DIGI and TELEMETRY OFF to see if we can make it through just ONE eclipse. That's all we would need to recover PCsat back into a positive power budget.
I will try this for the daytime passes over the USA this week (which will affect the evening passes over Europe).
The lowest power mode of PCsat has been with all BULLETINS and all DIGIpeating turned off. Also we disable 9600 baud 1 minute telemetry as well. Thus the only thing remaining was the once per minute single 1200 baud telemetry packet which is required to keep the heart-beat fail-safe reset timer tickled. What's new, is that we realized that if we switched the 1/min TLM to 9600 baud instead of 1200, we would further reduce the minimum transmit duty cycle in our lowest power mode. Thus halving our transmit current drain.
Unfortunately, our TRANSMIT power is already less than 10% of the overall bus power, so this move will only gain us about 5%, but worth trying... Our minimum transmit average current drain (1 packet per minute) is only about 16 ma out of the nominal 160 ma low power mode. Dropping this in half saves us about 8 ma. Who knows, maybe it is the straw that can give new life to the camel?
Anyway, when PCsat is in this minimum mode, the ONLY thing you will hear will be a once a minute half second noise burst (9600 bd TLM) and nothing else.
Sorry for the inconvenience. If you were planning a PCsat demo this week, let us know and we will turn it back on. (WB4APR@amsat.org)
PCsat WEB page http://www.ew.usna.edu/~bruninga/pcsat.html
ISS-APRS FAQ: http://www.ew.usna.edu/~bruninga/iss-faq.html
CUBESAT Designs http://www.ew.usna.edu/~bruninga/cubesat.html
APRS LIVE pages http://www.ew.usna.edu/~bruninga/aprs.html
APRS SATELLITES http://www.ew.usna.edu/~bruninga/astars.html
[ANS thanks Bob Bruninga, WB4APR, for the above information.]
I guess it's time for me to step forward out of the shadows. The behavior you're observing is being caused by me, N1JEZ. I'm the so called "Covert AO-7 Command Operator".
Before everyone gets all crazy, please let me try and explain a few things.
First, I asked to remain "covert" for a period of time because I did not want to have to deal with the inevitable flood of email that will result from my identity being known. At the time, I was in a critical phase of trying to command the bird and needed to concentrate on that task. There were a number of technical hurdles to overcome, not the least of which is dealing with 30 year old stuff.
I know I'm going to get a lot of email, so I've put together the following FAQ. Please read through it. Hopefully it will answer some of your questions and avoid you sending them to me. <grin>
Q: Tell me how the commands work.
A: Sorry, I _will not_ discuss any of the command details. Don't even ask.
Q: Tell me how the hardware works.
A: Sorry, I _will not_ discuss any of the command details. Don't even ask.
Q: What are the plans for AO-7?
A: I haven't foggiest! My job is to investigate what commands work and what commands don't after 21 years. It's really exciting, but tedious work. Imagine the thrill of seeing this antique accept your first command after all these years! For me, this is similar to the experience I had not long ago hearing the AO-40 24 GHz K Band beacon the first time. I've gone from techno to retro in a short period of time.
Q: I'm doing a satellite demo next Monday night. Can you make sure AO-7 is in Mode B?
A: Sorry, as I stated above, my only job is to test various commands.
Q: When it comes to AO-7. I'm mad as hell and I'm not going to take it anymore! Just leave it alone!
A: OK, take one of your little yellow pills and then send off a note to your favorite AMSAT official. Honestly, if you have concerns, voice them to Robin, VE3FRH or one of the Board of Directors. Everyone here is trying to do the right thing.
Q: How can I help?
A: Of most interest to me is how AO-7 "wakes up" as it enters sunlight. Also, any observations of simultaneous multiple modes would be most valuable. Yoshi Imaishi, JF6BCC is compiling an excellent list of observations. Please send him whatever you have. firstname.lastname@example.org. You can view the list at http://plaza16.mbn.or.jp/~palau/temp/AO7-mode-report.xls
Q: Can you tell us _anything_ about this satellite?
A: I can tell you that command attempts are successful. I've only tested a very limited number of functions, but it's very encouraging. I hope to be able to do a write up on all the fun I've been having. Maybe it will be in the AMSAT Journal or perhaps a presentation at the AMSAT Symposium later this year. (get your tickets now <grin>)
I still have a ton of work to do. So please try and keep the email to a minimum. I'll try and answer what I can.
[ANS thanks Mike Seguin, N1JEZ, for the above information.]
The K-Tx sessions have been discontinued due to increasing solar angle. We will post more detailed plans for the upcoming bad solar alignment shortly. The proposal currently under study is to move ALON forward ahead of the sun in several increments to approximately ALON=45. When the sun approaches 45 degs at this position, we will "duck" ALAT to provide adequate power, slow spin to maximize mystery effect (ME) and let the ME drift us around to approximately ALON=315 where we should re-acquire sensors and be able to return ALAT to 0. We can then follow the sun back towards 0/0 over the following ~45 days. This approach should minimize transponder "down" time to a few weeks, when the ALAT is not optimal and we are drifting in ALON due to the mystery effect. Timing of transponder and RUDAK windows, as before, will have to be shortened and moved to provide optimum squint.
N QST AO-40 S2 Downlink #=Wednesday only 2002-07-16 MA 036 120# 128 160 200 240 036 ---------1-----4-----3-----5-----7-----0-----1 MB | * | * | | * | * | * | RUDAK | | | * | | | | V-Rx | | * | * | | | * | U-Rx | * | | | * | * | | Passband | UL | VL | | UL2 | | | M QST AMSAT OSCAR-40 2002 July 16 ALON/ALAT ~ 6/2 Shortly we will further increase ALON to move ahead of the sun. *** See N-block for schedule.*** *** Middle Beacon OFF during RUDAK *** The AO-40 team would like your telemetry files! Please "zip" compress your daily telemetry files and e-mail to: email@example.com
[ANS thanks Stacey Mills, W4SM, for the above information.]
16 July 2002
After the problems reported last month, the satellite has returned to normal operation. During the period 14 June to 15 July 2002 reception of the 145.826 MHz beacon has varied between good and poor. At times there has been packet QRM and splatter from other users on the channel, and I have also experienced some local QRN. These problems have masked any possible effects of the low battery voltages.
The internal temperatures decreased by one degree C at the start of the period. For the last three weeks they have been very stable and are now -0.8C and -1.8C for battery and telemetry electronics respectively. Some increase in temperatures is expected in the next few months, but this increase always tends to be later than expected, from the eclipse predictions.
The battery voltage observed during daylight passes has decreased slightly. The average value observed was 12.8 with a range of 12.2 to 13.6 volts.
The spin period has varied between -349 and -527 seconds, with no particular trend observed. The value of 363 has occurred an unexpected number of times. There have been 316 Z axis, three plus spin, and 316 negative spin magnetorquer firings during this reporting period.
The SEU count rate has continued to remain stable at 1150 counts per day. Decoding the SEU binary telemetry shows six memory locations 39C0, 21C0 3EC0, 37B1, 180 and F96 have failed. These permanent memory failures tend to mask out the display of the less frequent failures, owing to the limited storage for this data in the satellite. A program for decoding the SEU packets (U2PKT.ZIP) may be downloaded from my website. URL details below.
The WOD survey of channels 1, 2, 3, 61 (X, Z, Y magnetometers and status) dated 22 May 2002 has been transmitted. This survey shows an unusually long spin period of 1800 seconds. This WOD may now be downloaded from my web site, details below.
The mode-S beacon on 2401.5 MHz. has been heard by Christian F1AFZ, and Roy VE7BPB. Christian reported strong signals, and has sent a spectrogram which clearly shows two carriers separated by 1200 Hz, ie. the modulation frequency. Roy reports signals S2 above noise, and has also heard a second carrier. He is using an 86 cm dish, with a K3TZ patch feed, and an AIDC 3731 converter. Many thanks for those reports.
I have also managed to hear the mode-S beacon, using a 60Cm offset dish with 5-turn helix feed, AIDC 3731 converter, and FT726 receiver. Signals were weak, just moving the S-meter above the noise. I positioned the dish in the garden for 20 degree elevation during the first part of the pass, and then repositioned in azimuth for the end of the pass, at the same elevation. I managed to hear signals from both directions. Beginners luck, I guess, as it was my first attempt to hear this beacon!
The operating schedule is unchanged.
ASCII status (210 seconds)
ASCII bulletin (60 seconds)
BINARY SEU (30 seconds)
ASCII TLM (90 seconds)
ASCII WOD (120 seconds)
ASCII bulletin (60 seconds)
BINARY ENG (30 seconds)
The ASCII bulletin (number 115) is currently a static message, detailing modes and frequencies of some of the older amateur radio satellites.
There are additional status blocks after each bulletin is transmitted, and between ASCII TLM and WOD.
The mode-S beacon is ON, nominally transmitting an unmodulated carrier on 2401.5 MHz. There is however a VERY low level of AFSK modulation which has been detected on strong signals. Telemetry indicates that the beacon has partially failed, and is delivering half power. This beacon is a useful test source for those testing mode-S converters, as an alternative to OSCAR-40. However the signals are very weak, and there is a lot of Doppler. Users should also note that the polarization of OSCAR-11 is LHC. Even if you can't hear OSCAR-11, your equipment may still be OK for OSCAR-40. Any reports of reception on 2401.5 MHz would be most welcome. Please e-mail firstname.lastname@example.org.
The 435.025 MHz beacon is normally OFF. However it can sometimes be heard when the satellite is being commanded by ground control, i.e., within range of Guildford, UK. When the 435 beacon is transmitting, the 145 beacon is normally OFF. The data transmitted is mainly binary.
Listeners to OSCAR-11 may be interested in visiting my web site. The web site contains details of hardware required and some software for capturing data, and decoding ASCII telemetry and WOD. There is an archive of raw data (mainly WOD) for analysis, which is continually being expanded, as new data is captured. Also included are some audio files, examples of each type of data transmitted by OSCAR-11, each one plays for about ten seconds. There are also examples of mode-S reception. All the audio files are zipped, so that they can be played off-line. These should help listeners identify the various types of data, and give an indication of the signal quality required for successful decoding.
The URL is http://www.users.zetnet.co.uk/clivew/
If you place this bulletin on a terrestrial packet network, please use the bulletin identifier $BID:U2RPT74.CWV, to prevent duplication.
73 Clive G3CWV email@example.com
[ANS thanks Clive Wallis, G3CWV, for the above information]
Neil W6FOG has announced a new net for satellite beginners. The first session of the net was held on Wednesday, July 17, 2002 starting at 1900 hours PDT (0200 UTC). The net will continue to meet on following Wednesdays at this same time.
The first half hour from 7 PM PDT (0200 UTC) TO 730 PM PDT (0230 UTC) will be for the first time users to get people's feet wet on working FM satellites.
The 7:30 to 8:00 time slot will focus on training for working all the satellites, what it takes, antennas, radios, tracking programs, and do it your self construction.
8:00 to 8:30 PM is the Question and Answer session.
All of the net details, including the check-in procedure are on-line at http://www.w6fog.net [Now http://www.w6fog.com as of September 29, 2002.]
[ANS thanks Neil, W6FOG, for the above information.]
ANS is still looking for additional Editors, if you are interested in joining the team please contact Robin Haighton VE3FRH@amsat.org
Link to the weekly report on satellite ...
ISS . RS-12 . RS-13 . RS-15 . AO-7 . AO-10 . UO-11 . UO-14 . AO-16 . LO-19 . FO-20 . UO-22 . KO-23 . KO-25 . IO-26 . AO-27 . FO-29 . TO-31 . GO-32 . SO-33 . PO-34 . UO-36 . AO-40 . SO-41 . SO-42 . NO-44 . NO-45 . MO-46
Please send any amateur satellite news or reports to the ANS Editors at firstname.lastname@example.org
Return to top
This week's AMSAT News Service bulletins were edited by AMSAT News Service Editor Lee McLamb, email@example.com