Re: Power meter accuracy

Cecil Bayona <cbayona@...>

With a RF Probe measure the voltage across the dummy load, Ohms law aught to tell you the power knowing the resistance and the voltage across it. The only other thing you need to know is if your RF probe measures Peak or RMS voltage, a cheap RF probe usually reads peak. If peak you will need to convert it to RMS voltage before calculating the power.

That will verify which meter is closer.

At 06:11 PM 2/4/2014, you wrote:

I did a bit of "domestic archaeology" in the attic this afternoon and
found a long-forgotten Autek Research WM1 SWR/PWR meter. Managed to even
find the matching wall-wart !! Put it in-line with the TenTec Argo 556
and noted a difference in power reading between the Argo and WM1. The
meter in the Argo shows 4 watts (dead center between the "3" and "5"
points on the front panel meter) and the WM1 shows exactly 3 watts on
the 0-20 scale.

So, which one is closer to the truth? In the big picture, it doesn't
really matter but I'm enough of a radio nerd to want to know closer than
"3-4 watts". Is there a way to determine which reading is accurate? Can
the WM1 meter cause that much power "loss"? I do not have any test
equipment here so it may be a moot point. Your comments welcome. Thanks
in advance.

Bruce AA5CO
4SQRP #664
SKCC #10643T
Cecil - k5nwa
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