Well, to make a not so long story even shorter: FORGET ABOUT QSK WITH THE FT-817!
I almost got a heart attack when I tried QSK. The RX/TX switching is done using some *very* noisy relays… well, at least some relay clicks like hell when you switch and are using the rear antenna connector. I haven’t tried the front one.
Believe it or not, the rig is actually full of relays clicking every now and then; usually when you change bands. I’m no professional when it comes to electronics, but using a lots of relays in a radio intended to be powered by batteries does not sound like a good idea to me – certainly the RX/TX switching at a power level of 5W can be done using diodes. Even if one must use relays, use vacuum relays for gods sake! The clicks coming from this radio are in fact much louder than those coming from my IC-765, which is something like 20 times bigger and heavier (and older).