Anyone know where I can buy a used transponder? I'm not a huge fan of paying $420 for a new one.

I figured that people getting out of racing would be willing to sell them. But, the only thing I can find on Ebay are little ones for RC cars.

I'd say your best bet is to put a WTB ad over on NASA forums and the like. They do come up once in a great while, but usually get snapped up pretty quickly. I sold an AMB direct wire transponder a year ago and now I'm kicking myself!

Will do. Thanks!