Topband: feeding 1/2 wave verticals

JAMESAMS88 at aol.com JAMESAMS88 at aol.com
Wed Aug 20 12:28:45 EDT 2003


On feeding 1/2 wave vertical's which I have done on 40 meters (65 foot for 40 
meters) by insulating the tower from the ground and matching with a coil to 
ground and tapping at a low impedance point (low SWL)  Also I had to add a 
small capacitance in series with the 50 ohm coax at the tap to get a 1 to 1 SWL 
which will almost cover the 40 meter band from 7.0 to 7.3 mh.  Works very well 
as a DX ant and also an excellent ant for 80 meters as a 1/4 wave and not bad 
even on 160 as a 1/8 wave vertical using base loading. The method of switching 
the matching to the different bands are done with relays. This system works 
for me on the three bands as I live in the city in a small lot and don't have 
much room for antennas. 
   This same procedure should work very well on 80 and 160 on very tall 
towers if a method of isolating the tower from ground can be found.    Just a 
thought   Jim WØNFL



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