Satellite Operation @ WØLFA
I recently set up a satellite station at WØLFA to see how well the GØKSC-designed InnovAntennas LFA Yagis, which work so well on VHF and UHF terrestrial weak signal modes, would work with the amateur radio satellites. Up went a five element LFA for 2m (2 LFA 5) and a ten element LFA for 70cm (70 LFA 10). The 2m LFA was tuned for 146 MHz and the 70cm LFA was tuned for 436 MHz to put them near the center of the satellite subbands, simple adjustments of the LFA driven element loop in each case. The LFAs were mounted vertically so that the aluminum cross-arm would not disrupt their highly-optimized, low sidelobe designs.
Both Yagis are relatively compact and sit about eight feet above ground on a Glen Martin Engineering ‘Quadpod’ tower mounted just behind the WØLFA shack. SSB-Electronic LNA SP-200 & SP-70 preamps with VOX sensed T/R relays are mounted on the tower close to the antennas to optimize system performance. Since satellite operation is low power, I opted for the simplicity of the VOX capability built into the SSB LNAs; less wires is always a good thing!
Positioning is provided by an AlfaSpid RAS rotator controlled by a rack-mounted AlfaSpid MD-01 controller. Rig is a Yaesu FT-847, the only non-SDR radio @ WØLFA, which I kept around solely for satellite use as our SDR rigs, as much as I love them, don’t (yet) have the full-duplex features needed for serious satellite operation. Satellite tracking is handled by SatPC32 software running on a Windows 7 64 PC. SatPC32 communicates with the FT-847 via a serial port null modem cable and with the MD-01 via a standard straight-through serial cable on a second serial port.
Here is what the XW-1 (Xi Wang 1 aka Hope OSCAR or HO-68) ham satellite sounded like at WØLFA on Aug 10, 2015 at around 03:30 UTC. XW-1 was launched in 2009 from the Taiyuan Satellite Launch Center in Shanxi province, China. After about a year, the transponder failed, however, the little ‘bird’ (68 x 48cm) continues to orbit and its 200 mW (2/10th of one Watt!) Morse code beacon continues to transmit. Note the manual Doppler correction! (I have since enabled the automatic Doppler correction feature in SatPC32.)
All of the antenna system items used here, from InnovAntennas, AlfaSpid, and SSB-Electronic, are available from the Force 12 Superstore.