[TowerTalk] Radials for a vertical array

[William Q Meeker]

I am planning to build a triangular 3-element 80-meter vertical phased 
array this spring and have been doing a lot of reading on the subject 
(primarily the TT archives and ON4UN's book). The elements will be on a 4/5 
acre lot adjacent to our residence (I just could not fit a four-square in 
the lot and honor setbacks from the road required by our county).

One remaining question is how to do the radials. I am planning 60 
1/4-wavelength radials for each element (this will not be done perfectly in 
all directions because of lot lines, but I see that as ignorable). I intend 
to just tack the radials to the ground or to use the K1VR "sewing method" 
that I found in the achieves to get under some of the brush that was not 
there 20 years ago.

I have been looking at figure 11-99 of ON4UN's book, where he shows bus 
wires emanating from a point at the center of the element locations, with 
the radial spokes terminating at the bus wire. It is not clear if this 
method is designed to save wire or to provide some kind of optimum radial 
system.

For two reasons, I would prefer to use insulated wire and cut all of the 
radials to 1/4 wavelength, and let them cross.

1. It is easier and less time consuming

2. I am worried about the long-term reliability of the bonds to the bus 
wire (which also makes me wonder if the DC connection is important, if the 
radials are wrapped around the bus wire sufficiently to have a good 
mechanical connection).


There was some discussion of crossing radials in the achieves, but nothing 
conclusive. Someone, at that time, suggested crossing radials could cause 
problems because of interactions in currents flowing in the radials and 
that it might be modeled, but that type of modeling is beyond my current 
abilities.

One other thing is that there are a substantial number of radials from my 
existing HF2V vertical (in a different part of the field) that would lead 
to some crossing radials. It would be difficult, but not impossible to get 
them all up, but is there any reason to do so (as I would prefer to leave 
the HF2V operational, if for no other reason, than to provide a 
comparison)? Most of the old radials came from insulated scrap wire, 
accumulated over they years.

73, Bill
K0KT





William Q. Meeker
Department of Statistics
304C Snedecor Hall
Iowa State University
Ames, Iowa 50011
Phone: 515-294-5336
Fax: 515-294-4040
Home Fax: 515-232-1323
www.public.iastate.edu/~wqmeeker