Date: Wed, 11 Aug 1999 11:05:02 EDT
Subject: from N0AH Radials and Arrays
Content-Type: text/plain; charset="us-ascii"
X-Mailer: AOL 3.0 for Windows 95 sub 18
First, a disclaimer- I am not an engineer- or technical expert- just a ham
who has asked a lot of people questions about radials-
To answer Doug's question about adjoining radials form various arrangements,
I have been going through the same question myself- specifically, radials
I have recently constructed a 80 meter four square in which each vertical is
place apprx 1/4 wave distance from one another and around 90 feet diagonally
from one another. As a result, many of my 1/4 wave insulated wire radials,
laying on the ground, overlap, inside the square formed by the
radiators......in other words, about 1/2 of my radials criss cross-
I asked as many published hams having various radial articles what to do
about this- as well as many seasoned lowband/topband DX'ers having four
The text book answer (ie:ON4UN 3rd edition) states that a copper wire
(referred to as a bus line) needs to be place in the center of the square and
that the radials, where they cross the line, need to be soldered at the
junction. (For my bus line, I am using bare 4AWG wire)
What you will actually end up with is two bus lines, running at 90 degree
angles, thus cutting the inside of your square into four pieces-
In my research, I have found two camps on busing radials together.
The pro's of doing so are that most broadcast station arrays bus their
overlapping radials together. The reason is to prevent cancellation of
return currents- As AA0RS told me, why build a race car then leave the tires
off? Of the 20 or so world class experts I asked the question of using a
busline, about 25 percent agreed to some point, it was necessary.
Also, using a bus line conserves radial wire......By using the bus line, you
keep your actual radial lengths shorter inside the array square- If you
didn't use the bus line, you would use apprx 2/3 more wire for the inside
radials to complete the length of each 1/4 wave radial.........
Now, for those who did NOT think the bus line was necessary, the theory(s)
seemed based on the the following statement:
"Because each vertical is it's own independent system, overlaid and
superimposed on commmon ground, the chances of intereaction is slight- as
each radial set can only take out whats put in".............That was one of
the technical reasons I sort of understood-
....although my translation stinks of a very detailed explanation, I think it
gets the point accross.
And of course there were a handful of ops who told me they saw no improvement
when they bussed their radials together- a few seemed disappointed over all
the hype of using a bus line etc........but no one said it hurt!
Ok, so what does all this mean??? Well, its a hobby-
I decided to go with the bus line because broadcast stations do it- and I
take the attitude it can't hurt things to try- I wont have another chance to
cut my prarrie grass down to where it is now as I mowed it to the bone to put
the system in- around 15,000 feet of 16AWG insulated wire spread out over
46,000 Sq feet. I also went from 30 1/4 radials to 60.......and did so with
1/2 the wire I would have needed by using the bus line-
In my research, real test data is sparce on this subject......but a lot of
hams have given me a number of ideas to handle radials involving an array-
My conclusions may not be your's or there's but I haven't heard two just
alike yet- Har!
Regrading Doug's other question........I'm not sure on criss cross radials
from different antennas- My 160 meter Inv L has 60 1/4 wave radials but my
80 meter four square radials are not crisscrossed with them although they
Any input anyone has on this subject, please poist it-- I've only used about
10% of book learning vs. 90 percent of practical experience in putting my
station together- It's great to have the reflector!!!
73 Paul N0AH
FAQ on WWW: http://www.contesting.com/topband.html
Administrative requests: topband-REQUEST@contesting.com