[TowerTalk] 80 meter antenna

[Jim Brown]

On 4/12/2012 9:52 AM, Bob K6UJ wrote:
> Since you have 80 feet of height to work with, I would string up a quarter wave vertical.  You only need 70 feet for
> a quarter wave on 80.  Then either use (4) elevated radials.  You cant beat a vertical, nice low angle radiator for DX.

I'll strongly agree with this. When I lived on a city lot in Chicago I 
had an 80M diipole at about 40 ft that I fed with parallel wire line. I 
used it on both 80 and 160M by tying both sides of the feedline together 
and feeding it against a counterpoise that consisted of a wrought iron 
fence and a few short radials.  It worked better that way on both bands 
than it did as a dipole.

Several comments about radials. First, when there are only a few 
radials, they are de-tuned by proximity to earth, so it's good to tune 
them to length by measuring pairs of them as a dipole and shortening 
them as needed to hit resonance.  Second, study K2AV's work on a Folded 
Counterpoise, which is a way to use shorter radials on 160M. You should 
be able to scale the recommendations for 80M. Third, when using 
on-ground or buried radials, length is less critical if you use a LOT of 
them. There are excellent recommendations about this in the ARRL 
Handbook.  N6LF's website is also a great resource.  The radial system 
for my 160M vertical consists of about 75 radials that vary in length 
from about 20 ft to about 120 ft, depending mostly on what is in the way 
of making them longer.

73, Jim K9YC