I finally got the Heil HM-12 working with the Xenyx 502 mixer so I can use my one mic for my TS-480SAT and my computer running Echolink, AllStar and D-STAR DV Dongle. I had problems but got some help from Bob Heil himself. Here is audio from my first two QSOs using the new setup:
Ivan from Austria
Manuel from LaPalma Canary Islands
Thanks!
Joe, N3FHW