A primary target is one that is not giving any transponder reply; they are
painting you strictly from skin reflection. Why would you think that the
altitude encoder has anything to do with that problem?

A bench check tells you that the box is working. It says nothing about the
antenna or feedline.

Jim



Over the last 4-5 flights, New York TRACON has been complaining that
they only get a primary target during the early parts of my flight and
thus have refused radar service. Of course, on my way back to the
airport, it would start working. Given that the transoponder was given
a clean bill of health from a bench check, the encoder seems to be the
next logical troubleshooting step. Replacing my pole antenna with a
blade-type (at the recommendation of the shop) does not seem like it
would be the solution to the problem given the symtoms.

Marco