SS, I used to have a little terra transponder in my little taildragger.
Must have weighed less than 2lb and drawn very little current - front plate was about 8 x 4 cm and it worked a treat.
I'll bet there'll be plenty of cut price pre-loved mode C transponders coming onto the market over the next year or so.
I don't agree that everybody should be forced to have one however I do not think that finance or space are such insurmountable obstacles as you suggest,
SB
