One thing that is over looked when moding a multi-bay antenna such as
the 4 bay folded dipole array is the interbay spacing. Depends on who
made the antenna, but this should be either 1 free space wavelength or
1/2 of a wave. Changing the element sizes will improve SWR, but
without changing the bay spacing you change the electrical beam tilt
of the antenna (your "pancake"). This may be useful in valley or on a
mountain, but generally not ok for plains. Also don't forget that the
phasing harness needs to be resized too, you will need to know the
velocity factor of the coax you are working with in order to do this.
Instead of all that, I can honestly recommend you try the Tram 1491.
Avalible from Repeater-Builder.com through Zimmerman Electronics.
We put ours up on the 146.64 repeater over the weekend and the
repeater works hella-good now. The "cutting chart" was a little
lacking in information, only giving 2MHz increments, but some dead
reconing and averaging was used to cut the antenna for 146.5. With pwr
adjusted for 50W fwd we had approx 200mW reflected.
The antenna has a price that can not be beat which will not break
anyones budget. I was going to rebuild a station master clone but the
cost of the RG-11, brass, epoxy, hot glue, torch to do so out weighed
buying the Tram.
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