[TowerTalk] Ladder Line and Coax

[2]

>
>Have been thinking of installing a simple antenna to
>cover the SE in contests and as a backup in general. 
>Was considering a inverted vee hung from the tower and
>fed with ladder line & tuner.  I want to cover only 10
>thru 40.  My question is this: my tower is about 100
>ft ftom the house and want to feed this antenna with
>ladder line near the ground, how do I handle that
>transition to coax? 

An efficient way to ground-feed a 1 or more halfwave inverted V is with a 
remote controlled L-network.  Fair Radio Sales sells a Collins c. 30uH DC 
motor driven variable-inductor that wurks well for such applications.  I 
used one in conjunction with a PM-DC gear-motor driven Johnson 
air-variable cap.  This type of antenna is the "Hertz".  It works well on 
other band where the antenna is multiple halfwaves. Feed-Z at resonance 
is 2000-ohms, depending on wire diameter.  (Larger diameter wire lowers 
the resonance Z.)    Thus, a fairly simple ground connection will work to 
perfection.  However, ground rods do not make the lowest-R HF ground.    
U.S. Army anti-tank mine research found that HF-RF typically disappears 
inches below ground.  So ground rods do a better job when they are buried 
horizontally just under the surface.

Cheers, Gale.

> A 4:1 balun, a 9:1 balun, other? 
>Is it even worth doing with the losses incurred due to
>the mismatch in 100 ft of coax?  Maybe a trap dipole
>or inverted vee would be more appropriate?  I just
>wondered if anyone had tried something similiar and
>how it all worked out.
>
>73, Stew  K3ND
>
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-  R. L. Measures, 805.386.3734,AG6K, www.vcnet.com/measures.  
end


List Sponsored by AN Wireless:  AN Wireless handles Rohn tower systems,
Trylon Titan towers, coax, hardline and more. Also check out our self
supporting towers up to 96 feet for under $1500!!  http://www.anwireless.com

-----
FAQ on WWW:               http://www.contesting.com/FAQ/towertalk
Submissions:              towertalk@contesting.com
Administrative requests:  towertalk-REQUEST@contesting.com
Problems:                 owner-towertalk@contesting.com