It was nice to hear K4SQC making his first contact on AO-73 last night with AC0RA.
Since the inception of the 73 on 73 award, over 100 unique call signs have been copied by AC0RA over North America. Paulo, PV8DX has been the only South American station I have personally heard and worked. Others in the US have reported working him.
I've seen several emails implying it is somewhat esoteric to make contacts via AO-73.
AO-73 remains the easiest bird to hear after the loss of VO-52. It doesn't not require much power or high gain antennas to use effectively. If you are not hearing it, you should not increase your power. Many stations are successfully using Elk and Arrow-style portable antennas with low-power QRP-style transceivers such as the Yaesu FT-817.
Pick a clear downlink frequency in the transponder's pass band. Adjust your uplink frequency until you hear your own signal. It's that simple. Make adjustments to the uplink frequency as necessary so that you do not "drift" across the pass band.
Manual tuning is probably best for most stations. Follow the rule of tuning/adjusting your higher frequency (the UHF uplink.) You can you use computer control via SatPC32 if you keep your fingers on the +/- buttons and pay close attention to the frequency.
It's exciting to see some new stations getting on the SSB birds and using AO-73 in their rover plans!!!
73 Clayton W5PFG