ARISS L-band operating parameters

ARISS US Hardware Manager Lou McFadin, W5DID provided a summary of expected parameters for those considering trying to make a contact with the ISS on L-band to VHF crossband repeater experiment planned for December 28 to January 3.

Lou reported, "The measured sensitivity of the L band receiver on a D700, as the radio aboard the ISS, is -105dBm for full quieting. The cable loss from the radio to the antenna is 9.3db. The antenna gain is zero db. The polarization is LHCP."

Extending the calcuations to cover the entire system path, Lou said, "The path loss at the horizon on L band is -160dB. That means the required EIRP for a full quieting contact at the horizon is 65dBm. The path loss decreases by 15dB at 80 degrees elevation so that means you can get full quieting with 50dBm in that case.

"To further elaborate if you use a 20dB gain antenna (a small dish), it is estimated that you can complete a QSO with 32 watts at the horizon or 1 watt at 80 degrees elevation."

The planned operating frequencies include:
Uplink: 1269.650 MHz FM
Downlink: 145.800 MHz FM

Lou, W5DID