ISCAT – a new experience

January 3rd, 2015

Inspired by an article, published by Rex, VK7MO, and David, VK3HZ, in the latest DUBUS [1], Ronald, ON7FLY, and I performed a first test in using ISCAT-B mode (by K1JT) for aircraft scatter on 23 cm. When looking on AirScout it doesn´t seem to be very challenging to have an QSO. But Ronald is obstructed by a hill in eastern directions and he didn´t expect to have an opportunity to work eastwards on 23 cm at all.

2014-12-27 16_37_03-AirScout - ON7FLYRonald is located in JO10LT and the distance is just 388 km. He uses a 44 element yagi with only 2 W at the feedpoint. On my side a 3 m dish and 150 W are in use. First of all we tried in SSB and were able to complete a QSO after a while. I could copy ON7FLY very weak, but readable. Then we tried in ISCAT-B with 30 seconds periods and it was amazing to see, that Ronald´s signal could be decoded even when only traces appeared in the spectrum.

2015-01-02 15_28_46-His signal can be seen in the center section (The drop outs are reactions of the AGC on radar noise). The above sequence could be decoded to:

2015-01-02 15_29_22-Since the periods of 30 seconds were far too long, we needed certain airplanes to complete. then we tried FSK441 with no decodes and switched to JT6M and completed the third QSO. In the meantime I found a hint in the above mentioned article, how to reduce the T/R periods to 15 seconds. So we completed a fourth QSO in ISCAT-B again in shortest time: 2015-01-02 18_02_00-


[1] Rex Moncur, VK7MO, David Smith, VK3HZ, Aircraft Scatter on 10 and 24 GHz using ISCAT: DUBUS Vol. 43 4/2014