>
>
>I am building a single 4cx400 amp, i am just about finnished with this
>project but need some help on the grid termination.
>
>Reading Measures web page it seems that 12.5, 50, 200, and 450 ohms seem
>to be the practical choices. Assuming I require about 30 volts drive on
>the grid, i was trying to calculate the drive power.
>
>Using square root P X R ,,i calculate that it is 20 watts into a 50 ohm
>load, or 5 watts into a 200 ohm load or 2 watts into a 450 ohm load. This
>does not include the voltage doubling or tripling effect of the matching
>toroid transformer. In the case of the 200 ohm load and the voltage
>doubling transformer i would only require 1.2 watts(square root P X R X
>200 ohms X 2 for a voltage doubler) In the case of the 450 ohm load that
>would equate to 500 milliwatts using a voltage tripler.
>
> What i would like to know if this is the correct way to calculate roughly
>the required drive power based on the required grid volts. I am using a
>QRP 5 watt transceiver otherwise i would just use 50 ohms and be happy.
>
>Thanks
>Byron
/\ For peak volts calculations, I use peak watts, not RMS watts. For
instance, 5w RMS = 10w-peak.
cheers, Byron
>
.
- R. L. Measures, 805.386.3734, www.vcnet.com/measures.
end
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