Topband: Inverted L Tuning - Solved

Charles Bibb zedkay at telepak.net
Fri Dec 5 12:02:01 EST 2008



<<It was my understanding that the coax braid should be connected to both the
radials and the base of the towers gnd system, but as you can see the the
minimum SWR and resonant freq. go crazy when I do.>>

A while back I posed an almost identical question to the group 
regarding whether or not the tower and its ground rods should be 
incorporated into (connected to) the radial system for the 
vertical.  My vertical is installed like an inverted L without the 
top horizontal section.  That is to say it is suspended vertically 
alongside the tower and about 3.5 feet away from it.

<<My first mistake was connecting the radial ground to my tower 
ground.  Here's
what fixed the Inverted L:

1) Disconnected the tower ground from the radial ground and the SWR improved.>>

WOW! I received exactly the opposite advice to the same 
question!  SWR is not an issue with my installation, as I use a 
remotely-controlled L-network at the antenna base and so can match it 
either way. In fact, I have used it both ways (the difference in 
tuner settings is small but significant), but haven't done any direct 
A/B comparisons on air (would probably take too long to re-tune 
between tries).

I was trying to find out which configuration caused the least amount 
of interaction between tower and antenna, and consequently which way 
resulted in less loss.

So, which way is best?  And why?

73,
Charles - K5ZK





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