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Old January 23rd 10, 10:09 PM posted to rec.radio.shortwave
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Default Question about matching transformer (9:1 un-un)

bpnjensen wrote:
[...]

The radio in question, BTW, is a simple DX-160 - it's front end is
pretty wide open anyway, but heck, why not? As long as I don't send a
big static charge through it, I figure I cannot do much damage :-)

BJ



I had a DX-150A in the early 1970s, and if I recall correctly, it
had an "antenna trim" control to peak up the input network for
maximum signal. The DX-160 may be the same -- the differences were
minimal, as I remember.

The trim adjustment would help match varying impedances to some
extent, but there could be cases where an input transformer would
help even more -- with a random impedance antenna on a wide range of
frequencies, it's hard to predict without making measurements.

Transformers work both ways, so one could add a switch for 1)
impedance step-up, 2) impedance step-down, and 3) direct connection.
Of course, an antenna coupler is another possible way to approach
the impedance issue.




With all good wishes,



Kevin, WB4AIO.
--
http://kevinalfredstrom.com/
 
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