HINTS AND KINKS FOR A FUN AND EASY HAM SPACE PROGRAM
By Bill Meara - N2CQR/HI8
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(This article was written in 1994. Some of the satellites mentioned might not be active now.)
Here are some ideas on how your average ham, armed only with fairly standard equipment, can get involved with space communications without going over the technological deep end or spending NASA-like megabucks. For the last year or so I've been dabbling in satellite operations. Using ridiculously low-tech gear, I've been surprised by the amount of educational fun that I've had with my little space program - my involvement in amateur space communication has rekindled some of the excitement that I felt as a ten year old kid watching the Apollo moon shots on TV.
A sensible first step in a ham space program is the acquisition of some simple satellite tracking software. Without an easy, sure-fire method of locating satellites and predicting when they will be within range, trying to work the satellites can be a frustrating experience involving much static and few signals!
The satellite tracking software is essentially a mathematical program that will display on a map of the earth the positions of objects in orbit. The characteristics of the particular orbits are described by what is known as their "Keplerian elements" or "Keps" for short. After you get the satellite tracking software installed in your computer, you input the Keps for the satellite you are interested in (available from a variety of sources) and suddenly you have in your shack a screen showing the precise locations of satellites of interest. Just tracking the satellites is a lot of fun. I thought it was neat to be able to look at my screen and know that at that moment a satellite was zooming through the night sky over Tokyo!
AMSAT is a great source of satellite tracking software and by joining this organization you will be supporting the Amateur Satellite program. For those readers who are not computer experts or who have relatively unsophisticated machines (I use a 286 machine with CGA graphics) something simple like ORBITS II will do the trick. You can get the KEPS right out of the AMSAT journal, via the packet bulletin boards or through the online Computer networks (I use COMPUSERVE). One tip: consult the Amateur Satellite Experimenter's Handbook from ARRL and learn what the various numbers in the Keps mean. You'll learn a little bit about orbital mechanics and it will make your satellite ops more meaningful. One other hint: make sure you have your computer or software clock on the correct UTC date and time. Incorrect settings are a frequent cause for "I can't hear the satellite" complaints. You may be on Eastern Daylight Time, but the bird is on Universal Coordinated Time!
All the old ham literature advises newcomers to spend some time listening before they first try to get on the air or before they first experiment with a new mode. This is a good idea even in the space age. Before you try to have some QSO's, spend some time trying to listen for the satellites. You'll have a lot of fun picking up signals from space, you'll get more comfortable with the software and you'll be preparing yourself for that first big satellite contact.
Here are some good candidates for satellite "easy listening":
RS-10, RS-12 and RS-15. These Russian made ham satellites put out very strong downlink signals on the 10 meter band. (See the August 1993 and February 1994 editions of QST for details on RS-10 and RS-12; see March 1995 73 for information on RS-15.) You really can't miss these satellites even if you are using simple wire antennas. When your software shows the bird approaching your horizon, start tuning around the beacon frequencies (29.357 for RS 10, 29.408 for RS-12 and 29.352 for RS-15). You'll hear the CW beacons first. When the beacon is strong, tune through the downlink passband (they extend about about 45 khz above the beacons) and you'll hear SSB and CW QSO's. Listening tip: Copy the CW telemetry and later consult the Satellite Experimenter's Handbook to decode the data (by hand). You'll be able to learn about the satellite's temperature, battery status, power output and other "fun facts!"
DOVE. Here is another good target for "easy listening." Sponsored by Brazilian hams, Dove is a nine inch cube that circles the globe sending out telemetry and messages of international good-will. At times, DOVE's voice synthesizer is activated and on your two meter FM receiver you can hear it say (in English) "Hi! This is Dove in Space!" ( "Hi" represents a bit of ham satellite tradition - the first OSCAR transmitted a continuous stream of CW HI's.) Unlike other Hamsats, Dove's digital messages are easily copied on an ordinary two meter packet station. Here's a trick for capturing signals from DOVE (without losing sleep!): leave your packet station on over night with the receiver tuned to 145.825. Leave the computer's storage buffer on. In the morning you're likely to find messages from DOVE on your screen.
Once you get the hang of the software and have some listening time under your belt, its time for a QSO! I'd heard that a ham's first satellite QSO is as exciting as his very first contact or first DX; I can confirm that - at least in my case - this is true. I was really amazed the first time I heard my own signal coming back from a spacecraft and even more excited when I heard someone calling me "through the bird".
RS-10 and RS-12 are excellent vehicles for a ham looking for his or her first satellite contact. RS-15 is in a higher orbit and thus provides better DX opportunities, but the higher orbit might make it a bit more difficult for a newcomer to use. Don't worry too much about Doppler shift. When I was getting started, the literature sometimes made Doppler shift (the apparent change in frequency caused by the satellite's motion) sound like a formidable obstacle. You will notice the Doppler shift and it is definitely a force to be reckoned with, but don't get wrapped around the axle trying to calculate how far frequencies will be shifting! Satellite operators are a flexible bunch and most will tune around a little to find the signal of a ham whose signal is being shifted by the forces of physics. I've found that dealing with Doppler is very much like dealing with drifting VFO's in the old days (or dealing with my HT-37 when its cold!).
Use RS-10! Because of its easily accessible HF uplink and downlink RS-12/13 is getting a lot of use, but RS-10/11 is relatively neglected, probably because of its VHF (2 meter) uplink. At the risk of encouraging a lot of chirpy CW, let me repeat a suggestion that allowed me to get on RS- 10 with ease: use a 2 meter FM transceiver for a CW uplink to RS-10. I tried this by simply using the Push to Talk as a telegraph key, but my signal was so chirpy that I couldn't stand listening to my own signal! In pursuit of a cleaner tone, I opened up my old Yaesu Memorizer transceiver, found the positive collector voltage line going to the driver and final, and inserted a little telegraph key jack. I closed the Push To Talk circuit at the mike jack with a little alligator clip and - presto - I had a CW signal on 2 Meters that allowed me to make plenty of contacts (using a "coathanger groundplane"). The signal isn't the prettiest CW signal on the bands, but I don't think it causes any interference to other amateurs. I found QSO's using this modified rig particularly satisfying: that 2 meter Yaesu FM rig was never intended to work CW DX! Also, doing that little modification made the rig (for me) less of an "appliance"!
This little modification also gave me the capability of working the new RS-15 satellite (two meters up, ten meters down) but I haven't had as much success with this bird as I had with RS-10. My modified Yaesu just doesn't seem to get enough signal up to the higher orbit RS-15.
One of the neatest features of the Russian "Easysats" RS-10/11 and RS-12/13 are their onboard robots. It took me a bit of trying but I was eventually able to work the robots of both the RS-10/11 and RS-12/13. Some observations: It seems that if more than one station is trying to use the robot at the same time the machine sort of "locks up". You might want to wait for a pass in the wee hours of the morning. (From HI8, I just waited for a pass that would have most of the footprint over the relatively unpopulated eastern Caribbean). Also, the robots are looking for 20 wpm CW. They will sometimes tell you to speed up or slow down if you are not at the right speed. You can do it with a straight key, but this is sort of "pushing the envelope." The RS robots are FB hams. They give you a QSO number, say thank you, wish you 73 and QSL (via DF4XW). Talk about "working a new one"!
After you play with the fast moving low orbit birds for a while, the prospect of finding a satellite that will stay overhead for a long period and will provide the opportunity for real, long-range DX is very appealing. When I added the Keplerian elements for the OSCAR 10 and OSCAR 13 satellites to my ORBITS II program, I was intrigued. Compared to the low orbit birds mentioned above, these elliptical orbit satellites have enormous footprints and linger overhead for hours as they rise to and fall from their very high apogees. In addition to the prospects for working some interesting terrestrial DX, I was attracted to the possibility of receiving signals from a device 24,000 miles out in space.
I bought a little Hamtronics down converter to allow me to listen to the two meter (SSB and CW) downlink signals from OSCARS 10 and 13 on my old Drake receiver. With these satellites so far out in space, the little "coathanger groundplane" that I'd been using on two meters wouldn't provide enough gain. Longtime satellite enthusiast Pericles Perdomo (HI8P) showed me a June 1990 edition of 73 magazine that contains an article on an antenna called "The Ray Gun." Using small copper tubing acquired from a refrigerator maintenance shop and some scrap wood from a local lumber yard, I soon had a five element two meter quad and was listening to OSCAR 10 and OSCAR 13! I kept the antenna at a fixed elevation of about 30 degrees so I didn't have to deal with the additional complication of an elevation rotor. Listening to the DX on these high orbit birds provides plenty of incentive to build a 70 cm transmit system. The five element 2 meter quad also proved very useful as a transmit antenna for RS-10 and RS-15 operations (in lieu of the coathangers!).
The Russian Space Station Mir and the U.S. Space shuttle provide additional challenges for hams who are not satisfied with mere terrestrial contacts. Both the Mir and the Shuttle have been active on 2 meter packet and 2 meter FM voice. As you can imagine, competition for contacts is intense, but receiving signals from these spacecraft is easy and at least half the fun. Here in the Dominican Republic, English doesn't normally come out of my two meter FM rig's speaker, but during a recent Shuttle mission, Ron Parise, WA4SIR, broke squelch in Santo Domingo from the Space Shuttle! In April 1995, I had one of the most exciting contacts of my life when U.S. astronaut Norm Thagard aboard the Russian space station Mir came back to my two meter FM call. Norm is a bit of a "rag chewer" so I was treated to a few minutes of conversation with an Astronaut in space!
Unlike all the satellites mentioned earlier, with the manned spacecraft you have to try to update your Keplerian elements frequently: on both the MIR and the Shuttle, rockets are fired and orbital characteristics change from time to time - out of date Keps could cause your computer to give you false information on the spacecraft location.
During Shuttle missions, the voice communication between the astronauts and the ground controllers is retransmitted on the ham bands by the Goddard Space Center Ham Radio Club (3860, 7185, 14295, 21395 and 28650 khz). When I first started listening for the Shuttle, I wasn't quite sure whether or not I had loaded the correct Keplerians into my computer. As I was working around the shack I had my HF receiver tuned to the retransmission frequency and I had my computer running the satellite tracking program. Just as my computer showed the Shuttle passing over the southern tip of Chile and Argentina, I heard one of the Astronauts comment, "We're now passing over the Southern tip of South America." Eureka! Keplerians confirmed! I felt like I was sitting in mission control!
If you really want to feel that your "in touch" with the Space program - there is yet another use for the tracking software: you can use it to set up an "eyeball contact" with the birds! Both the Shuttle and the MIR are big enough and low enough to be seen with the naked eye. Consult your computer for a pass that will have the spacecraft over your horizon within an hour or so after dusk or before dawn. In this way the spacecraft will be illuminated by sunlight on-high. Armed with your orbital data you'll know exactly when and where it should appear. I've seen the MIR, the Hubble Space Telescope and various Shuttles many times (I've even seen RS-12, but this was bit more difficult.) The big spacecraft are so bright that they are referred to as "flying Venuses" by the satellite tracking community. I don't know if they give out QSL's for signals received in the "visible light" band!
Be careful, because space communication is addictive and is likely to lead you into other closely related and time-consuming pursuits! An astronomical telescope has joined my radio gear in a constant attack on my sleep time! I've also noticed that those enormous Earth-Moon-Earth antennas that once seemed beyond the pale are starting to look interesting and do-able. I'm looking into radio astronomy...
Good luck with your space program. The sky's the limit! May the force be with you. Live long and prosper! 73 de N2CQR/HI8.
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