Topband: Asymmetric radials for GP antennas; Just in case others seek what I've just found...

[Chortek, Robert L]

Christman has written a number of excellent articles on this subject.
Some of which are in the ARRL book "Vertical Antenna Classics".  

FWIW, I have been using a base loaded 60 foot vertical on my urban lot
in San Jose, CA for the past 6 years.  The base of the vertical is
elevated about 3 feet and uses 12 elevated radials on 160 and 4 on 80.
Since the vertical is located very near one side of our 12,000 sq. ft
lot,  and right next to the house, most of the radials are on the roof
and cover less than 180 degrees of the compass (more like 120 degrees).
>From what I have read on the subject, there is some directivity in the
direction of the radials, and a loss of signal strength in those
directions with no radials.  

I have been able to work all over the globe, in every direction,
including the Pacific and Europe where there are no radials.   I often
get excellent signal reports from Asia (my most compromised direction).
While the signal reports would be better if I had radials in those
directions, I have learned that those of us with "constraints" must
simply do the best we can and work within our limitations.  Beyond that,
we get on the air and have fun.  

My advice to all those similarly situated is do not be discouraged!
Make the best of your situation, and then don't worry about your
limitations (this is not directed to Cormac, as I understand his post
was an observation about what information is available on this subject
of asymmetrical radial systems).  Too all others who might be
considering 160, do not let the compromises which must be made prevent
you from getting on the air and enjoying 160.  Good (and very good)
success can be had from a small urban lot - even with major compromises
in antennas and ground systems.  The signals won't be as strong as they
would in an "optimal" antenna system, but don't let the fact you can't
do what's "best" prevent you from doing the best you "can"!   

Good luck and  73,

Bob/AA6VB

Cormac Gebruers wrote:   I've been searching for clarity and hard data
on the effects of asymmetric radials on radiation patterns and
efficiency of a vertical as I'm installing a 21m vertical for 80/160 and
will have to live with a radial system that is significantly compromised
over a 180 degree sector.

I was a bit surprised to "not find" this subject dealt with in any clear
decisive way in e.g. the ARRL Antenna Book or ON4UN's otherwise
excellent Low Band DXing book (Did I miss it in either publication? If
so, just send me a "your an idiot" email and I'll crawl back under my
cabbage leaf suitably chastened).