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Old January 9th 05, 06:13 PM
Cecil Moore
 
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Ian Jackson wrote:
But how good is the efficiency when the balun/transformer is working
between completely the wrong impedances (which will be most of the
time)? My understanding (and limited experience) is that most of your
power simply heats up the ferrite.


Sorry, I don't know the answer. I operate my W2DU choke into close
to a pure resistance that varies between 28 ohms and 90 ohms. I
once measured the temperature of a #2 iron-core 4:1 commercial
voltage balun and got no appreciable temperature rise under varying
conditions but I don't know what conclusion can be drawn.

How to operate your all-HF-band dipole with a purely resistive
load of 28-90 ohms is described on my web page below.
--
73, Cecil http://www.qsl.net/w5dxp/notuner.htm


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