[AMRadio] You Won't Believe This

Geoff/W5OMR w5omr at w5omr.shacknet.nu
Sun Jan 2 09:27:16 EST 2005

> But.. To get the correct input power (required in broadcasting) you must 
> measure plate current not cathode current.  Properly insulated meters are 
> safe and reliable.  I agre its either static or magnetic field problem.

If you measure current from the filament transformer center tap to ground,
you'll have not only cathode current, but plate current, as well.  Just look
over at the grid current meter, subtract that from the plate meter, and there's
your plate current, AND it's in a nearly ground potential position in the 
series circuit.  

My 250TH rig is setup that way.

The plate current -used- to be in the HV line.  Now, measured in the filament
transformer center-tap, to ground.  Cathode Ground is returned here, as well.

73 = Best Regards,

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