At 11:42 PM 2008-12-04, Neil Carr G0JHC wrote:
>I have given away my early ON4UN books and only have the latest edition.
>
>I seem to remember in a previous edition, mention of an inductor in series
>with the termination resistor or as part of the matching network? I cant
>remember if it was merely part of the matching network or served another
>purpose.
>
>Can anyone remind me what it was achieving and where it was?
>It is no longer mentioned or shown.
>
>I have found one veiled reference in a Google search which suggests it can
>be used to "tweak" F/B in conjunction with the termination resistor, but it
>wasn't clear.
Hi Neil,
The first edition of ON4UN doesn't even mention the ewe.
In the third edition (1999), ewes are under Antennas and also Feeding
in the index (the ewe text is on page 7-46, with dimensions and
modeled performance on 7-43). John shows an inductor at the
feedpoint, between the 9:1 transformer and the antenna wire to tune
out capacitive reactance and improve the match. This shouldn't have
any effect on the pattern and the decrease in mismatch loss will be minimal.
In my models, adding a small amount of inductance to the load tends
to move the rear null in the elevation pattern to a higher angle. It
also increases the capacitive reactance at the feedpoint. The effect
will vary depending on the frequency, ewe dimensions, and real world
grounds, etc.
73, Terry N6RY
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