[Elecraft] K2 power output measurement accuracy?

[Rick Dettinger]

----- Original Message -----
From: "Don Wilhelm" <w3fpr at earthlink.net>
To: "Darwin, Keith" <Keith.Darwin at goodrich.com>; <elecraft at mailman.qth.net>
Sent: Wednesday, May 24, 2006 9:29 AM
Subject: RE: [Elecraft] K2 power output measurement accuracy?
> K2 - all it takes is a known non-reactive 50 ohm load.  I use 1% precision
> thick film power resistors, so I know my dummy loads are good to 50 MHz or
> more, and with these loads, I know the base K2 power indication to be
> accurate.
>
> If you have the basic K2, the power control circuits will adjust the power
> to make the RF voltage at the power detector probe equal to that required
to
> produce the requested power into a 50 ohm load -- but if the load is
> different than 50 ohms (as it will be with a 1.2 SWR), then the power
> indication will not be correct - tosay how far off it will be requires
> knowledge of the resistive and reactive components of the 1.2 SWR (all 1.2
> SWRs are not equal, the range of possibilities form a circle on the Smith
> Chart).
>
> 73,
> Don W3FPR
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With my K2 into a DL1,  my WM-2 meter shows up to 20 % higher power than my
DMM and slide rule indicates.  Is the DL1 likely more accurate than my WM-2
meter.  If so, I will recalibrate my K2 with the DL1 and DDM.  Than I will
have a stronger QRP signal and be able to work 300 new countries.  I could
also recalibrate my WM-2.  Also, I wonder if the K2 maximum output  power is
increased if the voltage goes up.  Just in case I need to cheat a little
with QRO  power (15watts or so).  But I promise not to get an amplifyer.
73 (72)
Rick Dettinger
K7MW