Make your computer clock is synchronized with WWV exactly. I've noticed the time sync problem on VO-52 (LEO) and especially doing downlink telemetry from MASAT-1 (LEO). The satellite is moving very fast so if your computer clock is off, your antennas will not be at the correct position. Since FO-29 and AO-7 are higher, they moving slower across the sky and are more forgiving with this time issue. Check regularly for updated Keps as they are changing for AO-73. AO7 and FO-29 have been around a while so their Keps are pretty stable. AO-73's Keps are still unsettled and so the resulting Doppler problems. LEOs seems to need their Keps updated more regularly then FO-29 and AO7. Again, I found this out when doing telemetry down loading on MASAT-1. And again, AO-73's circuits maybe not quite stable yet. GL, have fun, Mike, K9QHO