Richard W. Ehrhorn wrote:
>Congratulations! But I suspect you can squeeze another 5-10% efficiency out
>of it with more work. I mean, we're never satisfied, are we?
>
Efficiency is very hard to measure accurately, and the potential errors
mean that he might already have another 5-10% in fact... or it might be
5-10% worse.
Typically Ep errors could be 2% full-scale on the meter movement and at
least 1-2% on the multiplier resistors. Ip errors again typically 2% FS
on the meter movement and about the same on the shunt. These DC
measurement errors could be reduced to about 1% by calibration using a
good DMM, but that still leaves at least 5% error on the RF wattmeter.
73 from Ian G3SEK Editor, 'The VHF/UHF DX Book'
'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.demon.co.uk/g3sek
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