ISS bounce V: The QSO!

May 23rd, 2013

STS-133 International Space Station after undocking 5

(Copyright by NASA [Public domain], via Wikimedia Commons)

After a lot of tests and improvements have been done in tracking the doppler shifted signals, Jan, PA3FXB any I had another try around 1296.300 MHz this morning. Both of us performed compensation of the own doppler component as well in receiving as in transmitting. We agreed in using  the EME QSO protocol and periods of 30 seconds.

PA3FXB as received by DJ5AR

Jan appeared within my filter bandwidth as soon as the ISS became visible to both of us. His signal strength was peaking up to nearly 20 dB above noise and was easy to copy. The tracked frequency seemed to be stable until the ISS culminated. Then the variation of the doppler shift became so rapid that the compensation mechanism was not fast enough anymore. But that happened to the very last part of our QSO while we were transmitting our final 73s. So I can state that the best signal quality can be expected during the ascending and the descending parts of the pass.

In the meantime I received Jan´s recording. Listen how DJ5AR sounds on his side:

DJ5AR as received by PA3FXB

Many thanks to Jan for his cooperation and his patience in numerous tests before.

This success is dedicated to our fathers, who suffer from the same disease!

If you are interested in a try, do not hesitate to contact Jan or me. You can find us in the HB9Q 1296 MHz EME logger or in the ON4KST microwave chat, when QRV.