Amateur Radio via Satellites

When I was a young radio amateur, of course I had my handset with me everytime. When I was walking once through a forest and my radio stopped scanning at 145.9875 MHz, I could not believe what I heared. There was half of europe talking out of the speaker. It was Amsat Oscar 21 that I heared for the first time. From this moment on I was infected by the Satellite Virus.

AO-21 transmitting greetings in english and german. (MP3 145k)

AO-21 transmitting russian greetings. (MP3 23k)

AO-21 transmitting communication of the Eagle-Crew of 1969. (MP3 75k)

Because I had not enough transmitter power on the 70cm band those times I never worked AO-21 by myself. AO-21 was only a secondary payload on a commercial satellite. When this had finished its mission, the whole satellite was shut down. Here are a few audio files from AO-21, in 1994 AO-21 was transmitting for the 25th Anniversary of the first moon landing the communcation of the Eagle-Crew.

I made my first satellite QSOs via AO-27. This bird has opposite Up- and Downlink bands in comparison with AO-21, so transmits on the 70cm band. So I was able for the first time to work an FM-Satellite, because the 35 Watts RF-power on the uplink on 2m were enough. Here you can see my portable equipment with the possibility to record the activity to Minidisc.

Short log taken Jan. 14th 2001

SO-35 in APRS

Later I worked UO-14 in FM-Voice, via SO-35 I worked a few days before this bird failed in APRS and via the MIR 70cm repeater, just a monoband repeater in space thats unlikely, I worked with only 5 Watts into a HB9CV Antenna. It was a VHF-Contest weekend so there was poor activity on the Sats.

Look also in the QSL section for my satellite cards.

I was looking with high interrest at the start and also the first months of AO-40. After the problems in December 2000 causing the failure of the 2m TX, the command station was able to activate the 13cm TX after a few days. That days it was very important to get as much telemetry data from the satellite as possible to imagine what happened late December 2000. I was involved in the collection of telemetry data even though I could not been a big help because of my little antenna system. I tried a bigger antenna as often as possible. With that I had the problem of much WLAN noise of the city. I tried to cancel these noises in not pointing the antenna directly to the satellite. I increased the elevation so the satellite signal decreased but much more did the noise because it was getting out of the main lobe of the antenna.

By clicking on the nearby photo you will get one of the first telemetry packets from AO-40 that I've received by myself on the 2m band.

QSO with DL6DBN (MP3 669k)

QSO with F6GBQ (MP3 755k)

One day after the U/S transponder of AO-40 (70cm up - 13cm down) has been turned on, I was able to work through that bird for the first time. I used a 35 cm offset dish with a linear polarized Coffe Can Feed and a preamplifier from DB6NT. On the uplink I used a FT-790 with only 2 Watts RF-Output Power and a 9 element linear polarized Yagi Antenna with about 11 dB gain. That means about 25 Watts erp on the uplink. Note that up- and downlink were linear polarized, that brings 3 dB lower signals each way in comparison with circular polarized antennas. Even though I was using this minimal equipment, I was able to here my own SSB signals through the bird and to work 2 stations.

More information about amateur radio in space you will find at
AMSAT Germany and AMSAT USA.