The VK4YE 1 Kilowatt Linear Amplifier.

Metering.

Metering of the high voltage is best done by sampling the voltage across the bottom bleeder resistor. An appropriate multiplier resistor connects to the meter which is scaled to read 3kV or so. You then do not have the full supply voltage connected to a series of multiplier resistors, giving rise to unnecessary component failure risks.

The plate current is metered by inserting a 10 ohm 10W resistor between the "earthy" end of the plate transformer secondaries and earth. This requires you to lift the framed ends and tie them together. The plate current meter is connected across this resistor. While screen current is also included in the meter reading, it is not significant compared to the plate current. Incidentally, I made up scales for all meters by cutting out letters and digits that were printed out by an ink jet printer. They were then pasted on to a sheet of paper at appropriate positions to form a meter scale. The scale was then photocopied, cut to correct size, and finally pasted on to the face plate of a meter. It was a far neater option than attempting a freehand sketch.

I have found a useful type of high voltage stand off insulator at your local hardware store. The store will sell them as door closers! They are made from tough plastic and can be easily cut, filed and drilled. Several of them have been used in this project.

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