Here's a thought:

What is the theoretic feasibility of adding another set of six spreader arms
to a hex beam to support directors and an additional reflector to convert it
from two-element to four-element?

From a performance standpoint, as opposed to structural, would the
additional gain and front-to-back performance warrant investigation?

ChatGPT provided this:

A four-element configuration can potentially increase its forward gain.
In general, each additional element in a Yagi-style antenna can provide
an incremental gain of approximately 1 to 1.5 dB. Therefore,
transitioning from a two-element to a four-element design might yield a
total gain increase in the range of 2 to 3 dB.

EZNEC model is here:

Larry
WB6BBB

开云体育

Agree just get a spider beam as that it what you are trying to do with a hexbeam?

开云体育

开云体育

What might the additional gain figure be?


On Thu, 19 Dec 2024 14:25:18 +0000, "David Wright"
<dwright@...> wrote:

If you want more gain consider stacking them vertically.

Kirk,

Thank you for sharing your knowledge. Much appreciated.

Larry


On Thu, 19 Dec 2024 10:13:06 +0000 (UTC), "Kirk Kleinschmidt, NT0Z via
groups.io" <sohosources@...> wrote:

Hey, Larry,
The hexagonal beam (a 2-element Yagi) provides the "minimum effective dose" of directivity and gain in a lightweight, steerable package. It's claim to fame isn't gain -- as it barely has enough to make much of a difference -- but rather its low cost, ease of assembly, minimal wind load, minimal rotator requirements, full power capability without traps, etc.
Because the hex beam's elements are folded, the hexagonal beam must be considered as a "compromised" 2-element Yagi. Despite fan bois claiming that the antenna is magical, it isn't (save for the many benefits and featured listed above ).

The Spiderbeam is "less compromised" and has a much longer boom, which allows for additional wire elements, and additional element spacing. These factors give the Spiderbeam more gain and a better f/b ratio. It weighs about the same, has better performance, but is massively larger in space.
It's essentially a 3-element monobander on a full-size boom. This is the reference standard of the ages. To get noticeably more gain you need a longer boom (not necessarily more elements). This gets exponentially more expensive. And if you don't go for a design that's a lot larger, it's not worth the effort. for a wire beam the the Spiderbeam, going with fewer elements is also wasteful, in that the current design is already optimized at the intersection of size, cost and performance. Simply goingt o two elements has about the same cost and physical requirements, but with lower performance.
Dirty secret of the industry: Despite marketing efforts to separate them, all 2-element Yagis have about the same performance. All 3-element Yagis have about the same performance. All n-element Yagis have about the same performance. Log-periodic antennas with 6-10 elements have the same gain as a 3-element Yagi because only 3-4 elements are "active" on any particular frequency. Log-periodics have wide bandwidths, not huge gain.
What separates the men from the boys:?
Boom length. a 4-element Yagi with a 60-foot boom outperforms a 10-element Yagi with a 20-foot boom. You can't get huge gain without huge boom length.
Height above ground: All Yagis perform "to textbook" only when they're mounted a half-wavelength above ground or more. And they really come alive in a DX sense at 1 to 1.5 wavelengths above ground. The old adage "height makes right" is inescapable. I'd take a hex beam at 120 feet over a much larger beam at 25 feet.
My hex beam is at 23 feet. It (and all hex beams) wants to be at 45-70 feet, where HF Yagis come alive. if you can't get your antenna to at least 33 feet (a half wavelength on 20 meters) -- and preferably 45 feet -- the difference between any 2-element beam and any 3-element beam will be negligible, cuz they're just too low to perform to spec.
The hex is the most affordable and practical way to get "a little bit of steerable gain and directivity." That's it.
Do I like my NA4RR? You bet. Do I want it to be higher? Absolutely. And if I ever put up the two towers I've scrounged over the years, it will be. Would I rather have a Spiderbeam HD? Heck-yeah!? A few years back, when I put up the hex, the Spiderbeam seemed to be more difficult to build, and it was a bit more expensive. I took the "most known route," which was the hex, which I knew I could assemble and afford. If I had a time machine I'd have probably gone the other way.
The hex is the most affordable way to get a bit of gain and directivity. The Spiderbeam is the most affordable way to get (barring ridiculous extra expense) the "best performing" HF Yagi that rational money can buy.? To outperform a three-element HF monoband Yagi requires deep pockets and a very serious commitment. And if you think you need more gain, what you almost certainly need is more height.

My NA4RR at 23 feet is nicknamed the Death Ray, but a Spiderbeam at 120 feet IS an actual Death Ray. Such a setup is probably the most affordable way to set up a world-class HF presence. You have to have the space and zoning, of course, and having an exotic call sign will add another 20 dB to your signal, but still...

Best advice: Focus on height above ground.

Best of luck.

Kirk, NT0ZRochester, MN

My book, "Stealth Amateur Radio," is now available from www.stealthamateur.com and on the Amazon Kindle (soon)

On Wednesday, December 18, 2024 at 06:10:25 PM CST, Frederick Benson <nc4fb@...> wrote:

If you are an AutoEZ user, AC6LA's discussion of Spiderbeam antenna models may be of interest.?The AutoEZ Spiderbeam models?referred to in the discussion are free to download and use.?Fred, NC4FB