[TowerTalk] What kind of antenna is this?

[Kevin Zembower]

Wow, just going through all the literature I picked up at Hamvention, 
and I got lucky. I picked up a leaflet from the folks who made the 
antenna I was asking about. They're RadioWavz.com and the antenna is 
called the "Sentinel Hex Beam with 40 Short Add On." They don't list it 
on their website separately; you have to choose it as an option for the 
Sentinel Hex Beam. The picture at 
https://www.radiowavz.com/product/sentinel-hex-beam/69?cp=true&sa=true&sbp=false&q=false 
seems to show it, although the front-most pictured element seems to have 
a cover over it. The elements on the right and left side are more like 
the elements I saw.

So, it's not a stand-alone antenna, but a component of a 40M hex-beam. 
I'm guessing it's only advantage is to get the wire needed for a 40M 
hex-beam to fit conveniently with the hex-beam elements for the other 
bands on a multi-band hex-beam antenna.

Could it be modeled? Any other advantages, disadvantages or characteristics?

Thanks for helping me understand this antenna.

-Kevin
KC3KZ

On 5/23/22 15:13, Kevin Zembower wrote:
> Well, I think we're heading in the right direction, but the one in the 
> Wikipedia picture just has two wires between the end spreaders, and the 
> one I saw had five. Also, the one in the picture seems to have something 
> in the middle of it, and the one I saw didn't.
> 
> Another thing, the antenna I saw seemed to be part of one of the 
> (multi-band) hex-beam antennas. It didn't have an obvious feed-point; it 
> just formed one of the hex sides of the (single band) hex-beam. The 
> other multi-band hex-beam band antennas didn't have this antenna attached.
> 
> Here's another illustration. It could have appeared in the legs labeled 
> 1 or 2, or even could have been in the reflector legs, I guess, but that 
> seems improvable. Picture at 
> https://www.dropbox.com/s/1xk0rbc6a79g2zb/IMG_20220523_150816134.jpg?dl=0
> 
> -Kevin
> 
> On 5/23/22 14:55, Al Kozakiewicz wrote:
>> https://en.wikipedia.org/wiki/T2FD_antenna ?
>>
>> -----Original Message-----
>> From: TowerTalk <towertalk-bounces at contesting.com> On Behalf Of Kevin 
>> Zembower via TowerTalk
>> Sent: Monday, May 23, 2022 2:54 PM
>> To: towertalk at contesting.com
>> Subject: [TowerTalk] Fwd: What kind of antenna is this?
>>
>> There's a drawing at
>>
>> https://www.dropbox.com/s/8omfop6trejx211/IMG_20220523_144427650_BURST000_COVER.jpg?dl=0 
>>
>>
>> despite my very limited artistic talent.
>>
>> -Kevin
>> KC3KZ
>>
>>
>>
>> -------- Forwarded Message --------
>> Subject: What kind of antenna is this?
>> Date: Mon, 23 May 2022 12:22:01 -0400
>> From: Kevin Zembower <kevin at zembower.org>
>> To: towertalk at contesting.com
>>
>> Hello, all,
>>
>> At Hamvention, I saw a couple of antennas that seemed to be part of a 
>> multi-band hex-beam. They consisted of two rings about 2 inches in 
>> diameter, separated by about 3 feet, with 5 parallel wires between them.
>> On closer inspection, it seemed like a single wire double back and 
>> forth between the rings. I've also seen a similar arrangement on Naval 
>> ships, albeit much larger. They're mounted horizontally and seem to be 
>> fed from either end. The literature on the sales table might have 
>> referred to this as a 'Short 40.' The table was busy, and I didn't get 
>> to talk with the sales representative about it.
>>
>> Can anyone tell me the type or name of this antenna? Can it be modeled 
>> with NEC? What are it's characteristics, advantages and disadvantages?
>>
>> Thanks so much. Looking forward to learning more.
>>
>> -Kevin
>> KC3KZ
>>
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