Sadelco is now out of business, but their repair facility still sells refurbished meters. Sadelco made meters for CM.
http://www.sadelco.com/
http://www.rcbcal.com/home.html
My Sadelco 719E was about $600 when I retired in 1988. It was designed for analog signals, but I found it very useful for digital signals. The DisplayMax800 and DisplayMax 5000 ran about $1000. My wife gave the last 2 to me as a present. She tolerated my antenna experiments because she wanted a battery operated TV for use during power failures. The 719E on the left, 800 on the right.
DM5000 in use; Sony KDL22L5000. Disabled 1/10 dB for photo.
My Sony KDL32R400A has a Diagnostics Screen that gives signal strength numbers in one dB steps, so I got a TV and an SLM for the same price as a TV. Here is the calibration chart I made:
I have bought used meters on ebay, but only bought ones that I was willing to lose my investment or ones that had a return policy.
I was thinking of buying this less expensive meter from Solid Signal:
http://www.solidsignal.com/pview.asp?p=digiair-pro-atsc
Old FSMs gave a reading in microvolts:
Old chart that might be of interest to you:
