Burns,
I hope I have not been missing something major on my Kenwood TH-F6 HT, but I don't think it does full duplex. You can receive two channels simultaneously, yes. But I don't believe you can transmit on one while simultaneously listening on the other. That's the capability that you need to confirm you can "hear yourself" and confirm that you are reaching the satellite and the sat is sending your voice back to you.
If I'm wrong about the TH-F6a that would be a bummer! I'm looking for an excuse to replace it with a TH-D72a
You now have your excuse to get the TH-D72A. :-) The TH-F6A has two VFOs, but it is not capable of cross-band full-duplex operation for the satellites.
You might want to hold onto the TH-F6A, even if you get a TH-D72A. The TH-F6A has an all-mode receiver, which could be paired up with something like an FT-817 to make a small station capable of all-mode, full-duplex satellite operation. The TH-F6A's non-FM receiver is not as sensitive nor as selective as other radios like an FT-817, but the FT-817/TH-F6A combination makes for a nice station to show off at demonstrations.
73!
Patrick WD9EWK/VA7EWK http://www.wd9ewk.net/