my wife purchased a futaba 6xas radio for me for 155 bucks from a hobby store online, i opened the box and behold i have a 6ex-pcm radio. i can't seem to find any info on much here other then both are discontinued and the hobby store is telling me i have the upgraded replacement which sounds like a load of old salami. can someone direct me ? i am building my first lt40 sig plane and am eager to have a radio i can grow up with though i don't want something i don't know much about. can you also explain the pcm option on a radio? i understand its digital i was under the impression that most radios were. please help thanks