Re: K2 power meter/wattmeter question
Posted by
kc5wa on
Apr 15, 2005; 2:24pm
URL: http://elecraft.85.s1.nabble.com/K2-power-meter-wattmeter-question-tp377118p377124.html
Ron D'Eau Claire wrote:
>Mike, KT2E asked:
>
>How accurate have you found the internal power meter/wattmeter to be on the
>K2???
>
>Reply: ---------------------
>
>Mine is well within the 1/2 watt at 5 watts as stated in the specifications.
>
>
>Measuring RF power at QRP levels is really not difficult. A low
>forward-voltage drop diode from the 'hot' side of the RF line to a capacitor
>that goes to ground will give you an accurate peak RF voltage across the
>cap. Measure that with a high-impedance meter like most DMMs today. RMS
>value is .707 times that reading. To get the power, multiply the RMS voltage
>times itself (square it) and divide the result by the resistance: 50 ohms.
>
>
> my $.02 ========================================
Now! Someone pointed out to me several weeks ago that using the
Elecraft DL1 (dummy load)
with a DDM and a calculator ( the formula on the assembly sheet) works
very well and is accurate.
de "rc" kc5wa
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