Having used low power (QRP) HF equipment as an amateur I can tell you that it does work. However, the secret is in the antenna which has to be electrically matched to the specific frequency you are using. You can use an automatic antenna tuner but you still need some kind of external antenna on the aircraft. To make a long story short I must agree with the other people and say that Sat is a lot simpler than fiddling with a transceiver and antenna tuner while trying to fly the aircraft.