The Colombian army closed one of its bases near us, and the base commandante (who is a good friend) asked if I wanted any of the equipment in the electrical maintenance facility before he had it shipped to Bogota. Most of the stuff I already had, but I did pick up a B&K 200 mhz freq counter, an SL-501 Sinad tester, and a Helper RF-801 RF millivoltmeter. Everything was in like new condition, but the millivoltmeter is missing the rf probe. The probe schematic is in the manual, but without any component values. The schematic is shown below.
Helper instruments sold out in 1999, and the purchaser has long ago discarded all of the files for the RF-801.
If anyone has a probe they would sell, or can help out with the component values so I can build one, please PM me or email me at
unit399@yahoo.com. From reading the owner's manual, the meter won't function properly w/o the factory probe, and I hate to see a nice piece of equipment like this go unused.