The big limitation in using probe type RF voltmeters, is the probe. It becomes very difficult to establish a good low impedance ground above perhaps 700 MHz, making measurements questionable. This also applies to oscilloscope probes.
The impedance of any probe also decreases with frequency. Trying to make measurements in a relatively high impedance environment, may become impossible even at low microwave frequencies.
Working in a 50 or 75 ohm transmission line system has been the industry standard for a long time.
Stuart?
K6YAZ
Los Angeles, California
