Andy wrote:
Tucson approach had no problem seeing my ASW-19B, and vectoring airline
traffic round me as a climbed. I was not squawking anything except
"please let me stay here long enough to get enough altitude to get
home".

They could see a Kestrel back in the mid 1970's at 30 miles or so if I
recall correctly. One of the Tcson Soaring Club members did some
testing with them.

-Tom