[Ham-Mac] New House Ground

[Chuck Counselman]

[Mac content stated below. -C.]

At 12:26 PM -0700 12/20/03, Brian Short wrote:
>I think we probably agree that the one drawback with
>horizontal antennas at 80m is that they need to be about
>100 feet high unless what is desired is an extremely high
>angle of radiation for some reason (and there are valid
>reasons).

I agree.  However, it remains true that, for low-angle radiation, a 
balanced horizontal antenna beats a vertical antenna having the same 
(top) height, for _any_ height: less than, equal to, or greater than 
100 feet.

Both others and I personally have tested this assertion, both 
theoretically and experimentally, for New England ground 
(permittivity equal to 5 epsilon-sub-zero and conductivity equal to 
0.0015 S/m).

I have tested it theoretically by means of the USDoD/LLNL's Numerical 
Electromagnetics Code, version 4 ("NEC-4"), which I have compiled and 
run on my Mac.  [Warning: Neither NEC-2 nor Mini-NEC nor any of the 
user-friendly software that is based on these original programs can 
correctly model an antenna this close to ground having realistic 
permittivity and conductivity.  Of available s/w, only NEC-4 can deal 
with realistic ground in the near field.]

I have also tested it experimentally by comparing verticals 22 ft. 
and 33 ft. high with horizontal wires at the same (22 or 33 ft.) 
height.

Clem Moritz W1EVT, who lives near me, has tested it experimentally by 
comparing a full-size half-wavelength 80-m vertical (a 140-ft. Rohn 
25 tower with insulating sections) with a horizontal dipole at the 
same (140 ft.) height.


>The Low Band DX by ON4UN is quite good as is the Beverage Handbook; see:
>http://www.k7on.com/references/books.htm

I agree.


>It really is a big subject....

It's a relatively small subject if you simply compare the power 
gains, at 10 degrees elevation, of (1) a vertical antenna having the 
greatest height you can manage and with whatever ground and/or 
counterpoise system you can manage, and (2) a horizontal dipole at 
the same height above the same soil but with no counterpoise.

*Every* such comparison that I've seen, whether I or someone else did 
it, for any antenna height and with any number and length of radials 
for the vertical antenna, whether in-ground or elevated, with or 
without ground rods of any number, thickness, and length, and with 
any realistic ground but sea water, has favored the horizontal 
antenna.  Every one.  If you know of a counterexample, I'd like to 
see it; I really would.  I don't mean some antenna vendor's 
unsubstantiated advertising claim; I mean a written account including 
sufficient scientific and technical detail that we can meaningfully 
assess its validity.

If someone wishes to see a NEC-4 comparison for any particular 
antenna height and realistic ground parameters, and with any 
reasonable ground and/or counterpoise system, post the parameters to 
this list and I will post the results.  However, I'll do this only 
once or maybe twice.  After all, this is the Ham-Mac list, not the 
NEC list (to which I also subscribe, and where this topic has 
received much attention, from many very knowledgeable and experienced 
experts).

-Chuck W1HIS