Hams in space
Posted: 28 September 2008 06:32 PM   [ Ignore ]
Total Posts:  1078
Joined  2008-08-28

Several of the amateur satellites support FM voice operations.  The satellites are, in effect, FM repeaters in the sky.  The advantage is that anyone with an FM transceiver capable of operating on 145 MHz and 435 MHz and a simple directional antenna can access the satellites.  Most amateurs have a hand-held dual-band transceiver or handie-talkie (HT) that can be used since it takes only milliwatts of power on the uplink signal to access the satellite.

I have an HT that puts out 3 watts maximum power and which I’ve used to communicate through the FM satellites.  It’s a challenge compared to my “fixed” satellite station which is computer controlled.  A satellite tracking program controls the antenna rotors in azimuth and elevation and tracks the satellite I’m using from horizon to horizon.  The computer is also interfaced to my radio, so the program automatically selects the proper uplink and downlink frequencies and compensates for Doppler shift.  Once I set the frequency, I can concentrate on operating and not on manually adjusting frequencies as the Doppler shifts it during the satellite pass.

There is an amateur radio station aboard the International Space Station.  Many, if not all, of the ISS crew members are licensed amateurs and some crews are very active making casual contacts during their rest periods.  Other crews, like the current crew, are not so active.  This crew generally only makes scheduled contacts with schools and other youth groups as part of NASA’s PR program.  I’ve talked to the ISS as well as to the cosmonauts aboard MIR when it was still in orbit.  More about ISS amateur operations later.

I’ve attached a photo of the radio I use for fixed satellite communications.  It’s an Icom IC-910H that delivers 100 watts output on 145 and 435 MHz, SSB/CW/FM.  I’ll have to shoot a photo of my operating position that’s acceptable for uploading here.  There’s a 75KB limit.

Image Attachments

Glenn Miller - AA5PK
USAFSS/Rimbachvet Aug ‘72 - Jun ‘75

     It’s like CB, ain’t it? ››