Thursday, February 20, 2020

Panama City ARC is on Amateur Satellites: Demo on Feb 26 at 6 PM

The club satellite base station has recently been completed and tested on the air. Chris Bigelow VA3ECO will demonstrate its capability for a 6:20 PM satellite pass and a 7:40 PM satellite pass on Wednesday, February 26th at the clubhouse. Please be seated at 6 PM while Chris explains how the station works.

VHF and UHF Yagis pointed by azimuth and elevation rotators on our tower.

The amateur radio satellites have low earth orbits that bring them over for short periods once or twice a day. Our station uses the SatPC32 software to point our antennas in the correct direction as the satellite moves across the sky. The program interfaces with the control boxes for both azimuth and elevation rotators. The antennas are on a short tower outside the clubhouse. There are two antennas since the satellites use one band for the uplink and another band for the downlink. Our antenna has a crossed yagi for 2-meters and a 70-centimeter band. The crossed elements are phased to provide right-hand circular polarization.

A screen shot for the pcsat32 satellite software

The uplink and downlink operate at the same time or full-duplex. Our transceiver is the Icom 910h, which supports full-duplex on VHF and UHF. Since the satellites are traveling very fast to maintain their orbits, this causes a doppler shift of the signals. The Sat PC 32 software automatically adjusts the frequency on both the uplink and downlink for the doppler shift by sending commands to the radio.

The Icom 910h full-duplex VHF/UHF transceiver

This station can access the linear satellites as well as FM satellites. The linear satellites translate a band of frequencies on the uplink to the downlink. Both CW and SSB modes are used and multiple conversations can occur while the satellite passes over. The footprint of the satellites can support conversations across the US as well as into Canada and Central America depending on the pass. Contacts with Europe are possible.

Our members contributed various skills and donated equipment to complete the station. In particular, Chis VA3ECO on vacation from the Canadian Winter this year has been our mentor and leader for the assembly and testing. Chris calls this a "Cadilac" satellite station. It is much easier to use than a portable satellite station.