Topband: More on 160 dipoles

[Tom Rauch]

> verticals over nearly all openings, all conditions.  I've never,
> repeat never, seen a situation that would remotely support a 20+db
> difference due to antenna polarization! This includes both signals
> I've sent and those received, in comparison with others in nearby
> areas, etc. etc.  Big differences CAN exist in path conditions, for

Typically I see large repeatable differences ONLY when comparing a 
low dipole (around 100 feet or less high) with a high dipole or 
vertical over a path several hundred miles long or longer.

The average difference, over the past three years or so in many 
directions, is slightly in favor of my vertical when compared to a 
high dipole (~300 feet). A low dipole is consistently ten dB or more 
down from both the high dipole and vertical.

The exception is *virtually always* at sunrise peaks and during 
severe geomagnetic disturbances.

> top band stations. Contests, as you know, also wring out things pretty
> well. I think there are several things working as far as understanding
> 160 meter antenna effectiveness.  The first, of course, is efficiency.
>  With verticals this means length of radiator plus percentage of near
> field coverage (radial field) plus fresnel zone effects. 

My suggestion is people who simply can't make a vertical work have 
many things adding up wrong, not one major flaw like latitude. There 
is a strong human tendency to blame every result on one simple cause, 
and to oversimplify vastly complex problems. 

24dB is about the difference between my eight-foot mobile antenna and 
my 200 foot vertical. When I had a N/S dipole, I never received 
reports that indicated the dipole had  the performance of a mobile 
whip...ever.

As a matter of fact, N and S I had about the same results as E and W. 
A 15dB difference, let alone 24 dB, would stand out like a sore thumb 
even if you were NOT looking for it.  73, Tom W8JI
W8JI@contesting.com