Topband: Shunt feedint the tower
tony.kaz at verizon.net
Tue Feb 21 12:48:31 EST 2006
Well, 160M seems to be working fine with shunt feeding the tower. I like the
increase I got in bandwidth by making a multi-wire array parallel to the
tower face for the shunt feed instead of just using a #12 wire.
I picked up a UV resistant water tight plastic box to hold 3 vacuum
variable caps and a vacuum relay. This way I can switch what part of the
band I want to cover with a flick of the switch from the shack. I am using
an omega match.
I do have a few questions:
- With the 26V line to the vacuum relay, should I add an inline
choke and caps across the two wires? What value choke would be fine? Any
other things I should do with the DC supply for the relay so as not to have
- I will bring the coax into the box with a water tight connector.
Will hook up the shield of the coax to the ground side of the one cap. Plan
on running a #12 wire to the closest tower leg about 1. Using a zinc
ground clamp on the tower leg. Any reason I should use something other than
#12 wire for the ground?
- The coax will go to the coax switch mounted below this box. I use
the remote switch for selecting 40, 80 and 160M antennas. The switch is
grounded to the tower leg. The coax will be about 3 long, at most. Is there
any reason to put on several large ferrite cores that will slip over the
Buryflex between the cap and the coax switch?
- Any other input?
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