Satellite communications

I know that lots of people have made successful QSOs using an array of HT's, mobile units, and any number of home made antennas. I started similarly small, but had a couple of different design goals for satellite communications.

First, I am somewhat limited by my pool of equipment - I don't have old radios around or an HT that can be brought into service. I want to get as much use of what I have, but I also will need to make investments as they make sense.

Second, I want to be able to work satellites from my current base which includes a 75' feedline to the antennas on my roof. While mobile/portable operation is a goal, I'd like to start with more and pare down for portable work rather than the other direction.

Lastly, and perhaps most importantly, I want to engineer a solution that will produce reliable, repeatable results. As exciting as the first few contacts are, if I am to use satellites as a reliable means of DX work, I'd like to remove as much of the luck from the equation as possible.

Don't take my example as any sort of assertion that I think this is the best way, or even how anyone else should follow my lead! I just wanted to share what I got to work and the results.

The antenna is a Cushcraft 2m/440cm 3 element yagi mounted about 50' above ground and 15' above the roof of my apartment. It is mounted to a simple light-duty TV rotator. The bands have different feed points and elements but share a boom.

Each antenna is connected to an SSB preamp through 3 feet of 9913. The 2m is using 75' of RG-8X and the 70cm feedline is 75' of RG-213. The 2m antenna is driven by an IC-V8000 and the 70cm with the IC-7000.

I am currently limited by the antenna in a couple of ways. First is that I have no elevation control and the antenna to mast mount is fixed at 90 degrees. This means that I can work satellites as low as 7 degrees, but seem to lose them around 20 degrees elevation. Unfortunately, this also means that I am unable to take advantage of higher elevation passes which would have a lower path loss. I had also intended to run full-duplex mode and used the two different transceivers. Unfortunately, since the two bands share a boom, they interact heavily and the 2m transmission completely overloads the front-end of the IC-7000.

In keeping with my goals of making reliable communications, I'm going to make a few more attempts making only a couple of tweaks to the setup above. Ultimately, though, I will move to some antennas like the Gulf Alpha 70CM-8ELSat and 2M-5ELSat at about a 20 degree elevation on an 8' cross boom. I will replace the 6m beam for now since it will most likely be a while before that band sees any propagation more than the hour or so a month that I catch.

Many thanks to the AMSAT-BB list, Gary WA2AQH, and the SatComm Net hosted by the MBARC . If you're in the area and want to join in, it's every other Thursday at 20h00 on the KC2DAA repeater (144.225 pl 100.0)