I had been through the area five days before, controllers stated that they were having intermittent reception on my transponder. I later left their area and had no further problems on the flight. Just to be sure, I had a mechanic check it out, and he found no problems. Five days later, through the same Evansville, Indiana control area, the same problem reared its head...
Controller: Cessna 12345, I am not receiving your transponder.
Me: I don't understand that. I had the same problem with you last week and I had the unit inspected with no problems.
Controller: Well that's peculiar. In that case, maybe it has something to do with the 1950's technology equipment built in the 1970's held together by 1990's duct tape we're using on this end. Come to think of it, it's probably us.