[Amps] Single Band Amplifiers One Power Supply

Jim W7RY jimw7ry at gmail.com
Wed Oct 19 19:47:05 EDT 2016


I’m going to be setting up single band amplifiers for a contest station. 

How would you go about metering them? They will use an 8877 tube. Currently the amplifiers have Ian’s (GM3SEK) triode boards in them. They have never been on the air.
Looking at the old handbook article that had the single band 813 amplifiers, the builder put the plate current meters in series with the plate voltage. I too thought of that because broadcast transmitters use that approach too. But really don’t have the room in the existing chassis to set the meter back from the front panel. Although, and 3500 volts, they probably would not need to be set back that far...
How would you measure the grid current? Isolate the grids from DC ground with lots of caps and a 1 Ohm resistor?


I’m also looking for some small capacitance Johnson variable caps for both tune and load for them as well. They currently have vacuum caps which I really don’t want to use.

Thanks!
73


Jim W7RY/0
Now in Highlandville Missouri



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