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Old April 19th 12, 11:13 PM posted to rec.radio.amateur.homebrew
Dave M[_3_] Dave M[_3_] is offline
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First recorded activity by RadioBanter: Mar 2010
Posts: 30
Default trying to halve power to RF ammeter

Major Samwells wrote:
I'm trying to get some accurate power readings with a low power rig
(5 W) and an RF Ammeter. The trouble is that the ammeter doesn't
read quite up to the highest level of the transmitter and I need to
reduce the power to the meter by about half. I'm thinking a 3 dB
attenuator, but how am I going to find the oddball resistances and
what about resistor wattage? Is there any other way to reduce power
to the meter? Need something simple, quick-- but accurate. Thanks.



Use the calculator at
http://chemandy.com/calculators/matc...calculator.htm to
find resistor values. This calculator lets you adjust the resistor values
to values that you have, or can easily construct, and the recalculates the
attenuation with your new values.
Don't forget that you can use parallel/series combinations to get pretty
close to the ideal values. Mouser and Digikey stock a pretty wide variety
of resistor types and values. Be sure to check them out.

You'll need to know the impedances of your transmitter output and the
antenna in order to get correct R values.

Cheers,
--
Dave M
A woman has the last word in any argument. Anything a man says after
that is the beginning of a new argument.