[Boatanchors] Simple Relative Power Meter Circuit Needed

[Michael D. Harmon]

I have an old Swan 350 that I'm rebuilding.  The meter has two scales - 
receiver "S" meter and transmitter cathode mA.  I'd like to add a simple 
RF pickup inside the cabinet so I wouldn't have to use an external 
wattmeter for tuneup.  I figure some kind of a simple diode pickup in 
the RF cage and a sensitivity control fed to a switch on the front panel 
so I could switch the meter from "Plate Current" to "Relative Power 
Output" mode.  I don't need a calibrated wattmeter - basically just a 
field-strength meter feeding the meter switch.

Does anyone have a better idea?  What about the guts of an old Heathkit 
field-strength meter repurposed for the task?

Suggestions and tips welcome.

Mike, WB0LDJ