Gee, I surely agree with Grant, Larry! I've used EZNEC for MANY years, with
great results, and I've designed, built, tested and measured many wonderful
EZNEC designs - including some really complex "killer" antennas!
I do think that 28' top loading wires will be WAY TOO SHORT atop 50 ft. of
Rohn 25! More like 50-70' will be needed to resonate that tower. You will
probably do just as well with TWO top-loading wires in a Tee configuration! The
point is for the top-loading wires to extend the tower to 1/4 wave resonance on
160. Of course you could make an excellent 80m antenna with the 50' tower and
some modest top-loading wires approaching the length that you are considering.
GL!
If you are going to be experimenting with low-band antennas, EZNEC is a GREAT
investment
73,
Charlie, K4OTV
-----Original Message-----
From: Topband [mailto:topband-bounces@contesting.com] On Behalf Of Grant Saviers
Sent: Wednesday, February 04, 2015 11:28 AM
To: Larry - K1UO; Topband Reflector
Subject: Re: Topband: [Bulk] Top Loading wires
With an insulated tower, the cheapest EZNEC and other free NECs will yield good
results. Would you rather climb, cut, and trim a few times or spend $89 to get
EZNEC? Simple to learn. And the demo version is free eznec.com
Grant KZ1W
no affiliation, just a long term happy user
On 2/4/2015 7:27 AM, Larry - K1UO wrote:
> Could someone tell me the length of top loading wires (4 wires planned)
> needed to add to the top of a base insulated 90 foot Rohn 25g tower to
> maximize the radiation resistance on 160 meters. I understand there is a
> point of diminishing returns on the top loading lengths. The 4 wire angles
> will be around 45 degrees or as close as possible. If I knew how to model
> ,or even had a modeling program, I would attempt this already relatively
> simple task to many.
> From 50+ years of practical experience, I am ‘guessing’ maybe 28 feet long
> each?
>
>
>
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