ISS-Ham L band contact

For those of you that may be considering trying to make a contact with the ISS on L band, here is the data you need to help you decide on how to do it.

The measured sensitivity of the L band receiver on a D700 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. 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). You can do it with 32 watts at the horizon or 1 watt at 80 degrees elevation.

Good luck with your efforts.

I will try to answer your questions.

Lou McFadin, W5DID
ARISS US Hardware manager