Hi all, AO-51 is working very well in mode-L/U FM. On the two last passes here over Copenhagen [Denmark :-)] The signals on the uplink went through the "transponder" with nice downlink signal.
There is some slow fading, QSB, on the uplink when the satellite turns. That can not be avoided - but if you keep talking your signal will come up again.
Remember that the downlink on 435.150 MHz is left hand circular.
I use an IC-910H with 10 W on 23 cm. Antennas are two 19 turn helixes - gain about 18 dBi, right hand circular. Cable loss like 4 dB to the antennas from the transceiver.
Another observation is that it helped to use the compressor in the IC-910.
Managed to get a resonable downlink signal when the distance was about 3200 km.
Have fun. 73 OZ1MY Ib