RF probe for millivolts?
I need to make some trimmer cap replacements to an IC-735 and then do
a PL adjustment after replacing them. To do this properly (according
to the service manual) I need an RF voltmeter capable of measuring
the range of 40-400mV.
I have a DMM with an input impedance of 10M ohms. I was hoping to
construct a simple RF probe to the DMM and thus measure RF volts.
However, the way I understand it, most of the suggested RF probe
schematics (eg - the one in the ARRL Handbook) would only work in the
range of volts, rather than millvolts, due to the voltage drop on the
detector diode.
I have found a solution in the RSGB "Test Equipment for the Radio
Amateur" book, which unfortunately requires building 4 transistor
array to amplify the signal. A bit more work than I want to get
involved in unless necessary!
So my question is if anyone knows of a simpler solution for an RF
probe that can measure RF millivolts without an amplifier array?
Any suggestions greatly appreciated.
Larry VE7EA
|