[R-390] Carrier Level Meter findings

[Barry]

Last night, I did some more experimenting.  It turns out the internal
resistance of these meters is nowhere near 100 ohms.  It took 140 ohms shunt
resistance for these to read 1ma.  By my calculations, this would make the
internal resistance about 1260 ohms.

In any case, the meter will read 1ma full scale now.  I disconnected the
meter in my working R390A and jumpered this one in place.  The results were
somewhat dissappointing.  It works, but where the original meter will show a
60 reading, this meter will only show about 20.  I'm sure it has something
to do with the fact that the internal resistance is so high, but I don't
know why that affects things like it does.  I can even remove the shunt
resistor an the meter still doesn't give much more reading.

Looks like I'll either be building Jan's OpAmp circuit or finding some
originals.

Barry(III) - N4BUQ (who is going to have my own "intelligence agency" black
panels painted soon...)