Posted by
dave.wilburn on
Jan 14, 2008; 6:36pm
URL: http://elecraft.85.s1.nabble.com/K2-100-Power-investigation-tp458672p458675.html
Ok, I got all kinds of numbers off of the DL1. The Bird seems a touch
low, showing 80 - 100w across all bands. Every time I measure it a
different way, I get different numbers. Very frustrating. The W1
quit after about 5 min. The MFJ meter gives one reading, the Bird
another, using the DL1 and doing a calculation, goes crazy on 10&12m
but more stable, and once again different on others. Friend is going
to loan me his Bird, think it is a 4309, and we will see what it
shows. I have put the Bird between the K2 & the KAT100, and
transmitted and then ID'ed, and got the 80 - 100w. Am I chasing my
tail?
Dave Wilburn
K4DGW
K2/100 - S/N 5982
Don Wilhelm wrote:
> 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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