I will check my short stack of notes but I think it is buried in my main stack of random papers which is 2 ft foot high (at least). I emailed him but he ain't been around in quite awhile but I used his email rather than a PM so we'll see if I get an answer. one of his recommendations was a Motorola iirc but we would need a part #. I also asked him about checking the ground (which circuit) that he talked about.