It will be obvious if you look at the thread, Steve WA1QIX is on here...
...while I do not have one, I do know that he also sells these to all sorts of commercial broadcast stations, and the fact that it is on a PC makes it possible for them to do all sorts of neat things with it, beside simple mod monitoring.
_-_-
"sells these to all sorts of commercial broadcast stations" Is the REA AMM-SD1 Mod Monitor FCC type approved ?