Satellite Communications my cup of tea

Dusty Rhodes KB7ULT writes...


"Hi folks ……..


I have been a HAM for about eight years now and just have had nothing but fun with the hobby.


When I got my Technicians license, quit a few hams said “You need to up grade to General class, because you will only be able to work stations with UHF & VHF”. That was true, but hams in there nature are creative. With that in mind I dug a little deeper. As a result of my digging I found that I could work DX (long distances communications) via satellite. Oh yes satellite. So I made satellite communications my cup of tea.



I found that the most popular bird (satellite) was AO-13 (AMSAT Oscar 13). To work other stations through that bird I needed to transmit on one band, 440mhz upper sideband, and receive on 2meters, lower sideband. My first radio was the Yaesu FT-736R. In a lot of cases the 736 was the radio of choice, and I was no exception. But if your on a budget you can getaway with two radios. One for the up link and one for the down link, its tricky, but doable.



Now pointing a signal at the satellite will be a chore. Not only will you have to point your antennas left and right (azimuth), but up and down (elevation) as well. With a little ingenuity, some metal angle and two TV antenna rotors, that I picked up at the hardware store, I made my first azimuth and elevation rotor. By mounting one rotor on its side for elevation and the other in its normal configuration, it was an inexpensive way of getting the job done.



But gee, where to point the antenna? Well if we point it up into the sky and hope for the best, we still wouldn’t know when the bird would be there. These days everyone has a computer of some sort and there is lots of tracking programs on the Internet for, and here is that very inviting word ……FREE. Keplerian Elements (a mathematical schedule) for the satellite are available on the AMSAT page as well.



With the help of a few other hams and a lot of reading, I built my first two antennas, one for transmit and one for receive. Because I was excited about the new hobby, I wanted to get on the air ASAP. So the first antenna was on the 2meter side of the boom. Forgiving, quick and dirty was the plan and the three element quad was the answer. It was built in an afternoon, after getting drawings and equations to dial it in to the right frequency. Hearing the bird was fantasic. I cant tell you how much excitement there was in the shack when I heard just the beacon for the first time. Shortly there after I heard a conversation between a hams in Japan and California.



Well now, I can here the satellite. Lets work on the transmit side of things. I needed an antenna that was circularly polarized and I won’t go into depth on why, that will be something you need to read up on. Again, with a little reading in the Amateur Radio Handbook I found a nifty looking and easy to build 13 turn Helix.



With the Helix mounted to the cross boom, the tracking program at the ready, on my old 8088 computer, I waited for the next pass of AO-13 to appear. I started tracking the bird about 20 degrees above the horizon and sure enough I started to hear voices.



I found a spot on the pass band where there was no activity and began transmitting KB7ULT test, KB7ULT Test. Moving my receive frequency up and down the pass band I finely heard my own voice coming back to me. With my transmit and receive frequency lock together, I began to look for another ham to talk to.



At the time my shack was in the basement of my north Portland home and the ceilings where only about 6 foot high. I began with,… CQ Satellite, CQ Satellite, CQ Satellite this is KB7ULT, KB7ULT and standing by. When the ham on the other end came back with my call and then his, I jumped into the air about 6 foot 6 inches and came real close to knocking myself out on the ceiling tiles. After a short pause to get my act together I explained what had happened to the other ham. He laughed and congratulated me on my first DX contact and the new hole in my ceiling.



On 12/09/00 I made the leap to General Class and having a ball with HF."