Pete,
Thats what I will do. Test the influence of the 30 / 40 on the 5BA with
closed and open relays. If there are no interacton I will leave them
grounded as this was the advise from Natan of Force12.
Thanks aain to all for constructive advise.
Henrik
OZ1ING
-----Oprindelig meddelelse-----
Fra: towertalk-admin@contesting.com
[mailto:towertalk-admin@contesting.com]På; vegne af Pete Smith
Sendt: 26. marts 2002 22:22
Til: Guy Olinger, K2AV; Henrik Weiss; Towertalk@Contesting. Com
Emne: Re: [Towertalk] Force 12 antennas and tower relay grounding
At 09:00 PM 3/25/02 -0500, Guy Olinger, K2AV wrote:
>...
>When you have feedlines attached to these driven elements that are
>closely coupled, and depending on how long the feedline is to the
>particular DE, the unused DE's can appear either open at the center,
>shorted at the center, or worse, detuned to some odd frequency that
>affects another band.
>
>You need to know from F12 whether the design wants the unused DE's to
>be shorted or open, and design the feed length to the switch and
>choice of open/shorted when not in use to match.
Guy's got a good point. As I suggested in an offlist message to Henrik,
there's another consideration -- that 30/40 interlaced yagi has the
potential for interaction with the 15 and 10 meter elements in the 5BA,
depending on spacing and a lot of other things. Whether the 30/40
feedlines are open or shorted could make a big difference in this respect,
but the only way I know of to know for sure is to try it.
73, Pete N4ZR
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