[Collins] 321B-4 watt meter, accuracy of

[w9hak]

I have just compared my 312B-4 watt meter against my HP-410C with HP455A 
rf adapter using an 50 ohm non reactive load. My watt meter reads low on 
all bands of my 32S3 compared to the E2/50 values. Error values range 
around 25%, with the watt meter reading low. The transmitter is putting 
around 110-130 watts output depending on the band. The plate current is 
being set at 230 ma.

The 312B-4 hasn't been abused and has been in service since new. It 
reads reflected power if it's present. My initial thoughts are to leave 
the unit alone. Absolute power output isn't high on my priority scale. 
Having said that, what are the members of the reflector doing with their 
312B-4/5 control consoles? I would think the 1N82A diodes have seen 
better days and wonder if anyone has replaced them and the results of 
having done so.

Smith Bradford
W9HAK