[Boatanchors] 813 grid to filament short

[rbethman]

First issue - power supply draw 562.5Watts - yet output is 1500W?

So how do you get 1500W?  You have extra power coming from somewhere else?

Reality is fairly basic.  You never get something for nothing.

Evert time PEP comes up, all math and reality seems to go away.

The FCC has NOT figured how to measure PEP in the field.

None of us has NIST calibrated equipment unless you happen to work there.

N0DGN


On 10/1/2015 12:09 PM, Michael Clarson wrote:
> On the PEP issue, here is a brain exercise. I know there is a mathematical
> basis for PEP, and, that mathematically, 375 watts AM is 1500 watts PEP.
> So, lets assume (to simplify the math) that our transmitters are 100%
> efficient. On CW, if we output 1500 watts, PEP is 1500 watts, and our 100%
> efficient amplifier draws 1500 watts from the power supply. Makes sense.
> Now, if we go to AM, and we put out 375 watts 100 % modulated, the RF puts
> out 375 watts, and the modulator adds 187.5 watts. Total draw from the
> power supply is 562.5 watts, yet produces 1500 watts PEP. The 1500 W PEP on
> CW requires 1500 watt dissipation in a dummy load, yet the AM 1500 watt PEP
> only requires a 562.5 watt load. Perhaps a single PEP value is not he best
> way to specify transmitter power. --73, Mike, WV2ZOW