AO-40 FAQ
AO-40 FAQ
This FAQ arose out of discussions on the amsat-bb mailing list during 2002. It became apparent that there was a need for a concise, self contained set of answers to commonly asked questions by people new to satellites or new to microwaves, who wished to make use of AO-40. This document attempts to answer those questions. However, it does not necessarily represent official AMSAT opinion.
This is version 0.9a, dated 25 Aug 2002.
Feedback is always welcome, including contributions and ideas for further questions.
This FAQ is maintained by Steve VK5ASF (sfraser @ (AT) sierra.apana.org.au).
Other contributors are:
David Bowman G0MRF
Greg Dolkas KO6TH
Richard Limebear G3RWL
Stacey Mills W4SM
Reinhard Richter DJ1KM
Hasan Schiers N0AN
Mike Seguin N1JEZ
Jim White WD0E and the RUDAK Team
Charles Suckling G3WDG
Information was also obtained from:
AMSAT-DL Web site
AMSAT NA Web site
Bdale Garbee's 2002 AMSAT-UK Colloquium presentation.
This FAQ may be freely used and distributed, provided that credits and contributor details are retained. However, it is preferable that any updates to the FAQ be coordinated through the maintainer of the FAQ.
AO-40 is the post launch designator given to the long awaited Phase 3D satellite. It is the largest, most complex and most powerful satellite ever launched for the Amateur Satellite Service. It took over ten years to build and launch, and employs a number of new and advanced facilities never before attempted in an amateur satellite.
AO-40 is not just a single channel "repeater in the sky". It is a linear transponder, which means that it has a band of frequencies in which it will receive signals, and retransmit those signals unchanged. Thus a variety of modes are possible, including SB, CW, digital modes, etc. However FM is not acceptable, for efficiency reasons.
AO-40 was launched November 16, 2000 aboard an Ariane 5 launcher from Kourou, French Guiana. It was intended to achieve a Molniya orbit, but after the December 2000 incident its remaining fuel for the arcjet motor (ATOS) was used to insert it in a highly stable elliptical orbit with low inclination. This means that it has very long periods of visibility, at substantial distances (up to 60,000 km), and short periods at only a few thousand kilometres.
No, definitely not. AO-40 has more functioning transponder bandwidth than all other amateur satellites combined. It has a quarter of a megahertz! Yes, a lot of its facilities were destroyed in the December 2000 "incident", but is still retains a very high level of functionality. It is used every day by amateurs all over the world.
Shortly after launch, AO-40 was oriented for its first burn of the 400 N motor to primarily raise the apogee and also slightly raise perigee. The pressurization valve to the fuel tanks was successfully opened although gas flow through the valve was not as high as it should have been. The first burn occurred on the following orbit and lasted slightly longer than expected. A few minutes following this burn, the closed burn valves were noted to "pop" open in the telemetry. The pressurization valve was closed at this time and the tanks were not pressurized. The burn valves were cycled shut without incident. After considerable discussion the following day, it was decided to cycle the pressurization valve to see if it would function nominally after multiple cycles. Proper functioning of this valve was critical for subsequent burns. During this cycling (which should have been safe since the burn valves were indicated in the telemetry as closed) the spacecraft suddenly went silent.
It was subsequently determined that a plugged valve vent on the 400 N motor had prevented proper functioning of the burn valves and had probably allowed build-up of fuel pressure in the cooling coils around the motor bell housing. These coils apparently ruptured and in the process damaged one or (less likely) both of the burn valves. During cycling of the pressurization valve the following day, one component of the fuel apparently escaped from the damaged burn valve at the motor housing and mixed with residual second fuel component in the motor, creating a localised explosion. This pressure wave seems to have vented primarily through the centre section of the spacecraft, damaging the omni antennas on the opposite end and perhaps removing part of the covering from the omni end of the spacecraft. When the spacecraft was recovered several weeks later, its increase in spin rate indicated that a considerable amount of fuel had been lost from the spacecraft. It seems likely that only one component of the fuel escaped and after it had explosively mixed with residual second component in the motor area, the remainder of this fuel component escaped without incident through the motor region. If sizeable amounts of both fuel components had escaped at the same time, it is unlikely we would have any remaining spacecraft.
There are a number of facilities that still have not been fully tested. However the facilities that currently work include the following:
For the 2.4GHz downlink, most people use a down converter. These include modified ex-TV units such as Drake 2800 and CalAmp 31732 units (these types of devices tend to have noise figure that is inadequate, requiring a pre-amp, although some more extensive modifications address this), commercial units, or even home brew kits. On the antenna side, a two to three foot dish with a helix or patch feed seems to be the most effective. (Larger dishes can be used, but become difficult to aim). Helixes alone, even long ones, do not appear to be adequate for many passband signals, although can be used to receive the beacon and possibly the stronger passband signals.
The down converter typically feeds into a 2m or 70cm transceiver or a general purpose receiver. Warning! Transmitting into a down converter will normally destroy it, so if using a transceiver make sure it can't accidentally transmit. Some vendors are now selling devices protection devices to prevent this.
Most people use either the 70cm or the 23cm uplinks. On 70cm, when squint is at optimum (say less than ten degrees) then an Effective Radiated Power (ERP) of a few hundred watts is adequate. If squint is worse, more power is required. At squints of twenty five degrees or so it may be impossible to operate. It has been suggested that the L band (23cm) antenna is more directional than the 70cm antenna, so squint is more of an issue. At low squints, L band needs perhaps 1000 watts of ERP.
Note: ERP is determined by the transmitter power, the antenna gain, and losses such as feedline and connector loss. For example, a ten watt transmitter into a 17dB antenna, with 3dB of losses, will have around 250 watts ERP. If you have TOO MUCH power on your 70cm uplink, then LEILA may be invoked!
Note: RHCP (right hand circular polarisation) is used on all frequencies. If you're using a helical into a dish, the dish reverses it, so you must have a LHCP feed.
No! This was a commonly held view a while back. In fact the AO-40 problems have "forced" many amateurs to try 2.4 GHz, and they have been pleasantly surprised how unfounded their fears were. A 2.4GHz antenna is physically far smaller than one having the same gain for lower bands, and is quite easy to home-brew, or to buy and have shipped. For people without much exterior space, this is a great advantage. You can buy ready-made down-converters, so don't even need to see the very small components (such as surface mount) and tracks used at 2.4 GHz. But, if you wish to, you can home brew or modify commercial equipment, very successfully. Other than that, it's like any other band.
This is also called K band. AO-40 operates on K Band with 1 watt into a 23 dBi linear horn antenna. There is 50 kHz of bandwidth and AO-40's 400 baud BPSK telemetry is also transmitted within the K Band transponder. The Beacon frequency is 24,048.035 MHz. The transponder is 24,048.010 - 24,048.060 MHz. AO-40 only transmits on K Band - there is no uplink on this band.
Yes. For a few sources, see URLs at the end of this
document, including
Kuhne, SSB Electronic and Procom)
Based on testing by Mike N1JEZ, 36 dBd linear and < 2 dB NF will work. There will be QSB. Circular polarity is desirable. An example of the reception can be heard at: http://members.aol.com/mike73 - listen to the audio and decide for yourself.
Yes. Check:
http://www.g3wdg.free-online.co.uk/kband.htm
http://personal.eunet.fi/pp/oh2aue/24048.htm
http://personal.eunet.fi/pp/oh2aue/ja1ati.htm
http://members.aol.com/mike73
There are several reasons for this perception. Firstly, it is believed that the antenna may have been damaged. But there are other reasons too: the 2m uplink is not always on - it is used quite often for command functions by the team controlling the spacecraft. Also, The V-Rx and the U-Rx cannot be active at the same time - they are both controlled by a single bit, telemetry byte #1CA.
There have been reports of interference to the 2m uplink from various terrestrial sources, including pirates and atmospheric noise.
Finally, 2m beams giving the same gain as 70cm beams are physically much larger, and so less common. Thus many people are attempting 2m up-links at much lower signal levels than on 70cm. In addition, many people use 2m as their down-converter IF, so de-sensing of their receiver can be a problem when up-linking on 2m.
Now that AO-40 is operational, many commercial vendors have off-the-shelf gear available. Some URLs are provided at the end of this document.
There are a variety of ex-TV down-converters capable of being modified, these often appear at flea markets, online auctions and on the amsat mailing list. You can also buy home brew kits.
LEILA stands for "LEIstungs Limit Anzeige". Translated, it means "Power Limit Indicator". It is an uplink power limiting program that ensures that you are not putting a signal into the bird on using U/S (70cm up and 2.4 gig down) that would result in you being any louder than 8 dB BELOW the Middle Beacon (2401.323 approximately). If you try to transmit at a power level that would result in you exceeding this threshold, Leila will warn you briefly with an audible "Siren" on your frequency. If you do not IMMEDIATELY reduce uplink (transmit) power on 70cm, Leila will "notch" you out. At that time, you have to stop talking/transmitting, reduce power and start again.
Caveats:
Leila is not used on L band for the moment because the L band receiver AGC's have not shown a problem with excess power. The number of L band users is small. Those with excess power is even smaller. This leaves one Leila channel free for other uses. If L band becomes a problem, it will no doubt have Leila added.
RUDAK stands for Regenerativer Umsetzer fur Digitale Amateur-Kommunikation. (in English: Regenerating Transponder for Digital Amateur Communications). But as implemented in AO-40 it is much more than a regenerating repeater. It is a pair of fully programmable computers each of which has its own error corrected memory and associated hardware modems and DSP modems. It also controls many of the experiments on AO-40 including the GPS, the SCOPE cameras, two sets of temperature telemetry nodes, the MONITOR HF passive sounding experiment, and the CEDEX radiation experiment. There are other connections as well including to the CAN bus, the IHU, and a direct link between the two RUDAK processors.
The hardware consists of two mostly independent units, each with: V53 CPU running SCOS, 16 megabytes ECC RAM, 10 SCC channels, (8 with DMA support), two 9k6 hardwired G3RUH modems, one 153k6 hardwired BPSK modem, 4 DSP modulators, 4 DSP demodulators, CAN bus interface, and a FIFO buffer between the CPUs. This is all mounted on 4 double-sided, surface-mount PCBs in one box with 27,822 solder joints and 285 screws holding it together!
Its mission objectives are:
Through mid 2002 the 9k6 hardware modems have been in use. The following list shows the downlink channels that have been on at times. Because software and hardware testing is ongoing some of these may be on at times and not at others, and downlinks may change several times during a RUDAK window. Additionally, as DSP work progresses signals from those modulators may be in any part of the digital pass band.
| 9K6 0 | 9K6 1 | |
| RUDAK A | 2401.747 | 2401.720 |
| RUDAK B | 2401.867 | 2401.847 |
You can watch the digital downlink using WiSP. Setup two new satellites with call signs RUDAKA-11 and 12 and RUDAKB-11 and 12. Edit a text file of elements for AO-40 and make two copies, one called RUDAKA and the other RUDAKB. When RUDAK is on and you have a signal WiSP will attempt to run a pass for both A and B, select the one you are listening to. The old PB program will work as well if you set up the same callsigns as above in its PB.CFG file.
Reminder: the RUDAK channels (frequencies, transmission modes, operation times) are quite separate and different from those of the Middle Beacon!
Work with RUDAK through mid 2002 has focused on obtaining data form the GPS receivers, the CEDEX experiment, and testing the hardware to assure things work. The GPS data was a priority because the GPS receivers were expected to suffer radiation damage after about a year on orbit. The CEDEX data was the next priority because of the opportunity to collect unique data during the period of maximum solar activity in 2001. The SCOPE hardware has been tested and some striking pictures downloaded that show the hardware works and the promise of some cool pictures in the future. The DSP hardware has been loaded with some experimental code to test its functionality and the interaction between that hardware and the RUDAK processors.
A variable signal level (ZRO) test has also been implemented, which transmits a series of reducing strength signals, allowing you to judge your receiving sensitivity.
At present all uplinking is being done by RUDAK control stations on a small number of fixed frequencies. If they were published the level of interference would go up and it would take longer to do the work necessary to make RUDAK fully operational. When and if the point is reached where one of the processors can be opened for general use it's likely a DSP uplink frequency will be published. This will preserve the hardware uplinks for control station use and keep them interference free.
So far everything that has been tested. That includes:
Overall, the RUDAK hardware has worked well, except:
However much work remains. The process of testing the DSP hardware has just begun, the FIFO link between the processors has not been tested, one of the 153k6 modulators has been turned on but data has not yet been sent through it, neither 153k6 receive demod has been tested, the MONITOR experiment has not yet been turned on. The software controlled switches that select which receiver the 153k6 and DSP hardware listens to have not been tested. And general use FEC ground-station software needs to be developed.
First, it is not clear it ever will be. It is presently so difficult to establish links with RUDAK that it may never be practical to open one of the processor for general use; only a few hams would have the ability to talk to it reliably. That's why work is presently focused on testing the DSP hardware and software. The RUDAK team needs to find out if the DSPs will provide better links than the hardware modems.
It remains an objective of the RUDAK team that one of the processors be opened for general use as a BBS or perhaps for downloading SCOPE pictures. However links that can be closed with reasonable equipment and antennas will have to be developed first. Even then there will probably be constraints such as sharing downlink time.
There are several reasons:
It takes about an hour to upload the core software into one of the RUDAK processors. At times both are being used. Because testing and software development is ongoing software uploads occur often.
When GPS data is being collected it takes about one hour to download the data collected during one orbit. RUDAK control stations see only two orbits out of 5 so it takes hours of continuous downloading during each RUDAK window to keep up. An additional control station has been added which sees other orbits. But not all control stations are available all the time (and some windows are at really ugly times of the night)
Testing other hardware like the DSPs is an interactive process involving people at locations distant from the control stations. The Internet has made it possible to do things that way but not always quickly.
The control stations need some time while RUDAK is on to adjust and test their own ground equipment
Before launch it was expected that RUDAK could be on all the time, perhaps on a separate transmitter from the analog transponders and the PSK beacon, perhaps sharing. Neither of those is possible.
No. Not all windows are in view of a control station. But when the satellite is in view it's being used 90% of the time. The other 10% is because control stations occasionally suffer equipment failures and do have families and other obligations.
Scheduling the various modes AO-40 is always an interesting set of trade-offs. Feedback from people who use the P3 satellites has strongly indicated they want a fixed schedule that doesn't change very often so they can plan their operating. It's unfortunate the satellite can't be all things to all people all the time but it is a limited resource that has to be shared. The time and slot given to RUDAK operation is mainly driven by when the links will allow communication with the RUDAK control stations. The amount of time is driven by what needs to be done with RUDAK tempered with the desire to have the analog transponders on as much as possible. The pre-launch operational model for RUDAK anticipated it would be on all the time. Since that's not possible RUDAK and the analog transponders must share and everyone must live with that.
It's worth pointing out the number of stations on the satellite, though considerably increased recently, is still such that any good DX site is going to work them all in a couple of hours, which the schedule typically more than accommodates.
However the possibility of taking RUDAK out of the schedule when not being used by the control stations is being investigated. Note that this requires extra work for the AO-40 command stations, close coordination with the RUDAK controllers, and makes the schedule different for each orbit which causes confusion and consternation for some users.
The RUDAK 9k6 downlink creates distortion on signals in the analog pass band and on the PSK beacon. The PSK beacon distorts the RUDAK 9k6 downlink. The cause for this is not known. The distortion problem one of the reasons a great deal of time is being spent working with the DSP hardware. It needs to be determined if the same problem exists when the DSPs are used.
The possibilities are nearly limitless. They include:
The short term emphasis will be experimental - there is much work remaining (the TODO list for the RUDAK team is a couple of pages long).
Check that AO-40 is in range and in the correct mode for the equipment you plan to use. e.g. U/S bands
Tune your receiver to the beacon frequency on 2401.323 MHz +/- Doppler shift, and peak this signal by moving your antennas.
Next, tune your transmitter to a frequency that corresponds to a quiet area of the transponder. Make sure you stay clear of the beacon! This is important as you will not be popular if you cause QRM to other users or interrupt the telemetry. A good frequency for U/S usage is 435.700.
Now tune your S band receiver to approximately 35 kHz below the beacon and send a series of CW dots. By tuning the receiver plus and minus 10 kHz you should find your own signal on the downlink. Do not be tempted to swish the transmit signal up and down. Always keep the TX signal fixed and tune the receiver.
When you have found your own signal on the downlink you can lock the VFOs on your satellite radio or if you are using separate radios, make a note of the frequencies. (There is a very good Uplink/Downlink frequency chart on the Down East Microwave web pages that may help as well)
The above method works well if you do not suffer from birdies or de-sensing. If you hear more than one signal in the downlink, which appear to be coming from you while you are uplinking, it can be very difficult to identify the "real you". In this case only the signal which has a time delay is the true signal. If you find more than one of these then you may have a problem with your TX! Stations not coming back to you is another sign that you have not found the correct signal.
A small amount of de-sensing while transmitting is a nuisance, but can be tolerated provided that you do not increase uplink power to compensate or you run the risk of using excessive uplink ERP (and getting attention from LEILA). One easy way of checking for de-sensing is to see if the level of the beacon changes when you transmit (on the clear frequency you used to find yourself initially). Any drop in the level of the beacon is very likely an indication that you are experiencing de-sensing.
AO-40 is an inverting transponder - sideband users transmit on LSB and receive on USB.
With some combinations of radios and close antenna spacings, it is possible for the uplink to interfere with the downlink either in the form of "birdies" or reducing receiver sensitivity ("de-sensing"). Birdies may arise either locally in the shack, for example by using a 144 MHz for both the 2.4GHz receive and the uplink. The solution to this is to change one of the IFs - some stations use a 123MHz IF for the downconverter rather than 144MHz. Such birdies will not respond to increasing the spacing between uplink and downlink antennas. Birdies resulting from signals reaching the input of the downconverter or desensing will generally respond to increasing the spacing between uplink and downlink antennas. If this is not possible, then it will be necessary to insert a filter between the S-Band antenna and the input of the downconverter. Filters can range from simple quarter-wave open circuit stubs which provide a "short circuit" at the uplink frequency to "notch" out the interfering signal, to more complex microstrip designs which can also compensate for the residual VSWR of the stub at 2.4 GHz. See www.g3wdg.free-online.co.uk for examples.
There are a variety of tracking programs available, several of them free. Apart from a reasonably accurate setting of the computer time and your location, the only other thing you need is up to date "keps" (Keplerian elements). These are sets of numbers describing the orbit. The tracking program will use these, plus information about your QTH and the satellite, to predict the range, directions, squint etc of the spacecraft.
The AMSAT-NA web site has both keps and suitable tracking software.
The Middle Beacon transmits text describing the current schedule. This is normally expressed in terms of MA, and will show what bands and facilities will be operating. The AMSAT-DL site also has this information in the "AO-40 Update" section.
Basically, squint is the amount by which the antennae on AO-40 are "mis-aimed" with respect to your QTH. As the spacecraft orbits the earth, this value changes. Operations are only possible when the antennae are moderately well aimed, i.e., when squint is low. Many tracking programs display the squint. Note: with some tracking programs it is necessary to add 180 to ALON and invert the sign of ALAT in order to get proper squint displays (because squint depends on the physical construction of the satellite, and AO-40 is different to other satellites). The ALON and ALAT values may be obtained from within the telemetry or from the AMSAT-DL web site.
Experience shows that the S-band downlink signals falls off by
approximately 1 dB at 10 deg squint, 3.5 dB at 20 deg and 8 dB at 30 deg.
Above 30 deg the level drops quite sharply, and severe fading is also
experienced. A more exact prediction of signal level drop with squint can
be found in the links section of the AMSAT-DL website ("Beacon S/N Calculation").
Squint also has an effect on the uplinks. On U Band the signal drop with
squint is not too severe up to the point where the downlink squint begins
to have a major effect. What is observed is an increase in overall QSB,
particularly for stations uplinking with linear polarisation. Stations
using circular polarisation seem to suffer less from squint-induced QSB. On L Band,
signals fall off much more severely with increasing
squint compared to U Band, and even with a big system is difficult to
use the L-Band uplinks beyond about 30 deg squint. Unlike U Band, however,
signals to not appear to suffer from uplink-induced QSB, even with linear
polarisation.
Three axis stabilisation will mean that squint will be greatly reduced as the spacecraft orbits the Earth. To achieve it, there is still a substantial amount of work to be done by the command team. It's not a matter of uncertainty about the spacecraft. It's a matter of testing a lot of software, making sure all the contingencies like the mystery effect and protracted eclipses are covered, and that they can get back to spin mode if they need to. The original plans for 3-axis mode were based on a much higher inclination. Some of the software routines will need to be loaded in the spacecraft and tested in bits and pieces. Others can be tested in ground simulations. This is all under active development, but they do not want to rush it or back themselves into a corner from which they cannot retreat. They hope to begin testing with the next good solar angle.
ALON and ALAT define the attitude, or the direction in which the centre (the "z-axis") of AO-40 points. The spacecraft spins around this axis. As the 2.4GHz antenna is aligned along the z-axis of the spacecraft, the attitude also indicates the squint. Knowing the ALON/ALAT, the position of the spacecraft, and the location of the receiver, the squint can be calculated for any point in the orbit. Sometimes the terms BLON/BLAT are used - the "B" is short for the German word "Bahn", for path.
Imagine the spacecraft's orbit as lying on a thin flat plate through the centre of the Earth. This is called the orbital plane. Essentially, the z-axis stays in a fixed direction relative to that plate (but not to the Earth), throughout the orbit, in much the same way as a spinning top always points upwards.
ALAT is the number of degrees above or below that plane that the z-axis points (at perigee). (North is positive, usually visualised as "above" the plane). ALAT of zero is always desirable so that the antenna points at Earth (neither above nor below the Earth) regardless of the position in the orbit.
ALON is the number of degrees in the "East-West" direction that the z-axis points away from perigee when the spacecraft is at apogee (that is, how much it points along the thin edge of the plane, with East being positive). So ALON of 0 means that when furthest away, the antenna has the best pointing angle towards perigee, and hence towards Earth, and hence most useful gain. As the spacecraft orbits closer, the z-axis and hence the antenna will progressively point further and further away from the Earth, but to some extent the reducing range outweighs this.
Note: negative ALON/ALAT values are often expressed as numbers in the 180-360 degree range.
From the satellite's perspective, the sun appears to rotate around the satellite once a year. Thus, if the satellite were to remain earth pointing at apogee (ALON/ALAT = 0/0), the sun would, during a full year, alternately illuminate the sides -> back -> sides -> front-> sides of the satellite. Since the solar panels are on the sides, as the sun moves towards the front or back, illumination on the solar panels decreases to unacceptable levels and the satellite must be rotated.
Satellite orbits have a low point (Perigee) and a high point (Apogee), then
back around to the low point again. Like the dial on a clock is divided into 60 minutes,
a satellite's orbit is divided into 256 units of Mean Anomaly, or MA
for short. That is, Mean Anomaly means the distance (as around a circle) from
perigee. Each MA step has the same length in time. The use of 256 MA units instead of
365 degrees can be traced back to the very early days, where computing power was
very limited, and doing 8-bit math is very much easier than 16 bits. 8 bit gets
you numbers between 0 and 255. An orbit begins at MA zero at perigee, crossing
through MA 128 at apogee, and back through 255 to zero again at perigee. The
particular MA in an orbit is often used as a timer for various events. On AO-40,
it is used to schedule the turning on and off of various radios and other
equipment. The schedule is published on the Amsat DL web site under "AO-40
Update". So, if you want to use a particular satellite mode, you need to wait
for the satellite to be in the right part of its orbit (MA), and also visible to
you. Often you will find that both of these conditions are not met at a time
convenient to you, but be patient. The particular combinations of mode and
location on AO-40 rotate throughout the day, and throughout the
year.
Doppler is the change of frequency that occurs when an object (such as a spacecraft) has motion relative to you. It manifests itself as the frequency of a received signal being HIGHER as the spacecraft approaches you, dropping and going LOWER than the nominal frequency as it recedes from you. The amount of shift increases with both the velocity and the frequency of the signal in question. On AO-40 Doppler can be as high as 30 KHz on S band. Note: the spacecraft receiver experiences Doppler on your signal too. However, as your uplink is lower in frequency than the downlink, this can often be ignored. Also, other stations far from you experience different amounts of Doppler, so you can't just subtract Doppler and make a sked for that frequency!
ONLY the middle beacon is functional on the S2 Tx. We sure would use the EB or GB if we could. In the switching matrix only the MB can be hooked directly to the S2/K Tx. The command team once thought that they had a way around this by going through one of the Leilas in "bent pipe" mode. However, this was tried and does not work. On further study, the reason is that the passband for the S2 has sharp edge filters which greatly attenuate the GB/EB beyond the upper and lower edges of the passband. The reason for the filters is because the K Tx and the S2 Tx share the same IF connection and the edge filters were added to keep the K Tx signal nice and clean.
There are readily available programs that use a sound card connected to your receiver. The AMSAT sites listed at the end of this document have links to allow you to download the software. The P3T program also lets you connect in real time via the Internet and view telemetry. Software is available for Windows, Linux, and Macintosh.
Yes it is - the command stations really appreciate it. If you do capture any telemetry from AO-40 (even if shows as having bad CRC blocks) please zip it and send to: ao40-archive@amsat.org. It should be noted that during command activities or when the IHU-2 is in use, or when images from the YACE camera are being downloaded, there might be periods without telemetry. Note: the AMSAT-NA web site has information on the telemetry format.
These are for command use, they are the line numbers for the command used to
make this change.
AMSAT DL web site http://www.amsat-dl.org
AMSAT NA web site http://www.amsat.org
AMSAT UK web site http://www.uk.amsat.org/phase3d.htm
AMSAT-BB mailing list - to subscribe, send "subscribe amsat-bb" to Majordomo@amsat.org
K5OE's site http://members.aol.com/k5oe/
JE9PEL's site http://www.ne.jp/asahi/hamradio/je9pel
Macintosh software for telemetry and YACE: http://www.goldensquare.net
Kuhne Electronics - DB6NT (http://www.db6nt.com)
SSB Electronic
(http://www.ssbusa.com)
Procom http://www.procom-dk.com/)
Down East
Microwave (http://www.downeastmicrowave.com)
Homebrew high performance kits and filterswww.g3wdg.free-online.co.uk
Parabolic AB (http://www.parabolic.se)
Keps Communication (http://www.keps.it) - L/S Band equipment