A friend of mine passed away a while ago, and his widow has asked me to help her sell off the aircraft stuff that he acquired. One of the things we came across was the Becker transponder I mentioned in the title. Is there any easy way to determine if it is in working condition? I don't have the plug for the back or an antenna, likely they are at his place, but I don't have them at the moment. Any suggestions? JImChuk