I recently acquired a used S 402 M beam. It was originally purchased in
1992. The loading coils were purchased later and, I am told, are a bit
different from the original ones. I installed it at 130 ft and used the
7.050 dimensions in the original instructions. The SWR is 1.0 at 6.904 and
climbs steeply as the frequency is increased. I measured the SWR as the beam
was raised from 35 ft upward and there was only a small change upward.
I suspect that the later coils installed have changed the desired element
dimensions. Here are the dimensions from the manual I used:
DE 43 ft 5 3/8 inches. Refl. 44 ft 5 3/8 inches. Does anyone have
different dimensions for 7.050?
The instructions say the coax center conductor should be connected to the +
terminal on the coil tap terminals. There are no markings on the DE coil so
I have assumed that the + terminal is the one on the right looking down the
boom toward the DE. Does anyone know if that is correct?
Thanks, Dan, N5AR
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