Re[2]: TopBand: Feeding a grounded tower

[George Guerin]

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A quick comment to Steve & Tom's notes:

Steve Zettel wrote:
     
> If I go ahead and use unbroken EHS from tower to grounded guy anchors (the 
> base of the tower is definitely grounded a la Ufer and ground rods), what 
> is the best way to feed the tower for 160M, or is there a best way? Should 
> I consider breaking each guy at least one place, and if so, where?
     
     Tom, W8JI wrote:
     
"Hi Steve, 
     
Consider this. If you run an inverted L up between uninsulated guy lines, 
it is almost like shunt feeding the tower anyway as far as losses and 
unwanted resonances are concerned.
     
Ten feet of spacing on 160 is .02 wavelengths. Common sense tells us we 
should never expect a two meter antenna less than one inch away from a 
mess of wire to be unaffected by coupling, so why do we thing 10 or 
twenty feet on 160 makes a difference?
     
Even 50 feet of spacing on 160 is well within nearfield, whether it is 
ground radials or guy lines.
     
If you are a serious op, insulate the guy lines, put in a good ground 
system, and get rid of the problems. 
     
73 Tom"

I vote for a shunt fed tower or inverted L also.

It is easy to hang an inverted L 10 feet out, it will shock excite the tower 
anyway.

There is a fine article in May 1975 Ham Radio on shunt feeding towers by John 
True, W4OQ.  A number of hams in my area have been using this method for years.

There is a nice article by Gary Breed, K9AY, on shunt and monopole tower feeding
in one of the Low Band Monitors, edited by Lance Johnson Digital Graphics.  
Owner is K0CS.  It looks good too.  One of the locals uses a combination of two 
parallel shunt feed rods to broaden the SWR curve and therefore bandwidth it can
be fed without a tuner in line.

George, K8GG


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