Re: K3s driving a KPA1500 - how much drive power is nominal for 1500 watts? #kpa1500

Bob McGraw - K4TAX
 

That display should be indicating OUTPUT power.  

I suggest you use an external meter of known accuracy and a 50 ohm dummy load of known accuracy.  Measure both the input to the amp from the transceiver and the output of the amp as indicated on the external meter.      From your earlier numbers, they appear to be of some noted inaccuracy.

Also note that just because a dummy load says 50 ohms on the label is no assurance it is actually 50 ohms.   I have 2 of which neither are actually 50 ohms.   One is 13% high measuring 56.5 ohms.  Since most ham power meters are measuring voltage referenced 50 ohms, any error in the 50 ohm load will likewise show as an error in power measurement.

Based on ~15 dB amp gain and 1500 watts output into 50 ohms Resistive, the drive power should be 47.5 watts for a gain of 14.99 dB.

73

Bob, K4TAX

On 2/4/2020 10:34 AM, Jim Denneny wrote:
Adrian, I mean 1500W as indicated on the led power bar whatever that means - input / output.

73, Jim K7EG

Join Elecraft-K3@groups.io to automatically receive all group messages.