At 09:23 AM 2006-10-04, Eugene Hertz wrote:
>Do you think it might be feasible to place an 80m trap at the end of
>the longer leg of the ocf, and extend a wire beyond the trap for
>160m. The idea would be to use only one of the coax conductors
>against a radial field for 160, but use the antenna as a OCF using
>both conductors for 10-80?
>
>In that way, I can get both a balanced 10-80 meter ocf AND an
>inverted L unbalanced antenna for 160 using the same installation
>(not at the same time, of course!) Any one know what the existance
>of a trap and extra wire beyond the trap might affect the OCF
>performace when being used as a regular ocf?
>
>Just wondering your thoughts. I will add that several folks have
>reported excellent results with the carolina windom, but I do not
>mention that here because it has som other baluns involved that
>might complicate any calculations/modeling of the idea I have
>above. So I have listed the simpler buckmaster just for ease of discussion.
Eugene,
In addition to the excellent comments you have already received, it
is worth noting that the 80 meter trap will only "disconnect" the
extra wire on 80m, so operation on 60m and up will be impacted drastically.
Furthermore, the 6:1 balun will be in the signal path if you use the
OCF antenna as a modified inverted L on 160m (with or without the
trap). Depending on how the balun is designed, it may appear as a
series inductance and likely a series resistance as well. It would
be necessary to characterize the balun impedance for common mode
signals, which it may be designed to attenuate significantly.
73, Terry N6RY
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