Hi, topbanders
I was out in the yard this afternoon, checking on a few things before the
storm moves in:
First, I rigged a remote vacuum relay, switchable from the shack, from the
feed-point of the vertical TX antenna to
ground. I wanted to see how much noise was being re-radiated for the
Beverages to deal with.
Happily, it seems that my Beverages are not close enough to the TX antenna
to pick up any additional
noise, at least when compared to the ambient local noise. My vertical TX
antenna is not grounded. It
"floats" above ground and is fed through an L-network. With the TX antenna
tuned up, I could tell no
difference in received noise on any of the Beverages between TX antenna
grounded and un-grounded.
My vertical TX antenna runs up parallel to the tower in the same way as the
vertical portion of an
inverted L does, about three and a half feet away from the tower. There is
a KT-34XA at the top (90
ft) of the tower. My tower is grounded for lightning protection to several
ground rods at it's base, but
it is NOT tied in to the ground radial system for the vertical TX
antenna. Should it be?
Next, I rigged the relay to attach the tower base to the radial ground
system. While, again, I found no
difference in the noise that the Beverages hear, there was a noticeable
change in SWR of the TX
antenna between adding the tower to the ground radial system and not. The
change is easily tuned out
by adjusting (remotely) the L-network, so no problem there.
My question is: Should the tower be part of the radial ground system, or
not? Which way introduces
the least amount of loss into the system?
Charles - K5ZK
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