In a message dated 98-01-21 06:30:34 EST, you write:
<< Sounds like you have already done what I would like to do.
I now have the land and was wondering if I could use Alum mast
to make my 4 sq. I do not have the ice and snow problems here
in Tennessee. Please tell me what you have found works and where
you obtained the material. How much ground system/ elevated or what?
Do you use rope guying?
Tnx & 73,
Jack K4IBP .-.-. >>
Hi Jack, I will give you a brief overview of the vertical mast system for my
80m 4 square and if you or anyone else would like more details, we can do that
"off line" via direct E mail. My system is 1/4 wave high and 1/4 spaced. I
use 120 radials each;; however, my experience tells me that starting with 30
works and when you increase, you double each time to a max. effectiveness of
120. The switching is a W1FC designed, formerly "Colatchco, Inc.", which was
a part time hobby business started by W1FC, Fred Collins; the late W1CF, Dana
Atchley; and myself (the business logistics guy). The Colatchco design is
referred to in ON4UN's book "Low Band DX'g". Further development of phased
switching has been astutely accomplished by Comtek Systems, Jim Miller, KF4HK,
who I have a lot of respect for.
OK, the verticals: The verticals start with 2" OD, T-6, 6061 alu tubing,
telescoping and are 65 ft tall. There is a reducer section about 80% of the
way up to bring the alumin. down to about .5" where a whip antenna is
positioned. I haven't kept too close to tubing sources but I would suspect
that Tex Towers is a good source. The GREAT thing about this vertical is
that it has a sail boat type "tabernacle base" so that you can easily pivot
the vertical down and one "average 220 lb, 6'2", 50 year old, ex GI" can lower
it (I also know a ham's XYL who could lower it, or me, too) . Coming down it
will act like a long piece of spaghetti and you'd swear it should buckle/crimp
but it won't. This is a tribute to W1FC's mech enginineering talents. The
vertical has a top hat about 2/3 up consiting of 3 #12 wires about 8 ft long
which terminate to insulators where a light weight dacron rope acts to
continue as a guy line. The other guy line (the lower one) is up about 1/3
and is attached to a floating SS ring. The base impedance runs about 36 ohms.
1/4 wave RG11 feeds each antenna. It is a hell of a performing antenna with
gain that I estimate at at least 5 dBi; low angle radiation and F/B of 25 db.
Sitting here in the Northeast, the unsolicted comments about the F/B from the
SW and western US when testing to the N/E is phenomenal (not to disregard the
comments from the DX stations). I am not speaking for W1FC, but I know he is
quite consumed in Microwave R&D so I would suggest that inquiries about the
verticals go to me and the phase switching aspects to Jim Miller
(kf4hk@juno.com) and further reference to ON4UN's book, to which W1FC
contributed all of his research and necessary data. Hope this is of some help
to you and others. Regards, Steve Davis, K1PEK
DAVIS RF Co., Commercial wire/cable, RF connectors, custom cable design.
Discounts to hams.BURY-FLEX ? low loss HF-microwave coax;FLEX-WEAVE? aerial
wire. Registered trademarks of Davis Associates, Inc.
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