Re: K2/100 - Power investigation

Posted by Don Wilhelm-4 on Jan 14, 2008; 5:57pm
URL: http://elecraft.85.s1.nabble.com/K2-100-Power-investigation-tp458672p458674.html

David,

The diode in the DL1 recitfies the RF and you read the DMM in DC volts.
The DL1 uses a peak reading detector across half the load, so the DMM
will read 1/2 of the zero to peak RF voltage.  At low power levels (less
than 1 or 2 watts), you should add the diode drop to the indicated
voltage before calculation of the power, but at higher power levels the
diode drop is not significant.

BTW: The power formula in the DL1 manual has a small error that shows up
when calculatiing low powers.  The proper formula can be simplified to P
= 2x (Vdmm + 0.15)^2/50  - that is: add 0.15 to the DMM reading, square
it and divide by 25 - the 0.15 term is an assumption for the diode drop,
those who would like more precision can measure their particular diode
forward voltage drop.

73,
Don W3FPR

David Wilburn wrote:
> With the DL1, when you do the calculation to get the power level, what
> do you measure with?  V-AC or V-DC?
>
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