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Old January 24th 10, 07:00 AM posted to rec.radio.shortwave
bpnjensen bpnjensen is offline
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First recorded activity by RadioBanter: Jul 2006
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Default Question about matching transformer (9:1 un-un)

On Jan 23, 2:09*pm, Kevin Alfred Strom
wrote:
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/


Mssrs. Maus and Strom, thank you! I think I will concoct a device
soon to see what happens with it.

Bruce Jensen