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Author Topic: If Trapless Yagi's Were "Better" Don't You Think  (Read 12379 times)
WB3CQM
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Posts: 201




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« Reply #15 on: January 07, 2013, 05:43:52 PM »

Please give me the call sign of these engineers , individual you spoke with . I will contact them my self. But people will say any thing to make a sale !

A friend of mine had a TH6DX up at 50 feet plus a A3 we ran many on the air test. He running a KW . Me using 100 watts, He could NEVER beat my Quad on receive or transmit . He took them down and put a 3 el Steppir up and DXing changed to the better for him.

Sorry They said - HE Said - They Said - You Say !

Read "Array of Light "

Besides that traps are subject to water and spiders getting in them.

 Another friend of mine had hy-gain and crushcraft trapped beams and gave up on them and switched to Force 12, never to go back to trapped beam. Because of moisture and spiders in the traps.

Traps are a thing of the pass IMHO

End

73 JIM
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KA7NIQ
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Posts: 312


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« Reply #16 on: January 08, 2013, 09:13:55 AM »

Please give me the call sign of these engineers , individual you spoke with . I will contact them my self. But people will say any thing to make a sale !

A friend of mine had a TH6DX up at 50 feet plus a A3 we ran many on the air test. He running a KW . Me using 100 watts, He could NEVER beat my Quad on receive or transmit . He took them down and put a 3 el Steppir up and DXing changed to the better for him.

Sorry They said - HE Said - They Said - You Say !

Read "Array of Light "

Besides that traps are subject to water and spiders getting in them.

 Another friend of mine had hy-gain and crushcraft trapped beams and gave up on them and switched to Force 12, never to go back to trapped beam. Because of moisture and spiders in the traps.

Traps are a thing of the pass IMHO

End

73 JIM
LOL, my "whole life" would improve, if I put up a 3
element SteppIR too!
Understand it has been many many years since I spoke to the engineers at Hy Gain, so I do not recall who it was I spoke to.

But, use your common sense here, for a minute.
You make trap triband yagi antennas, a trapless design comes out for a triband yagi, what DO you do ?
Allow this "superior design" to take your sales ?

Heck no, you test this antenna, to SEE if it is really better then your design. And if it is, then you copy or improve it.

AS far as "HE Said - They Said - You Say " goes, it is highly unlikely, IMHO, that your Quad with 100 watts would beat, let alone equal, a TH 6DXX with a Kilowatt.

LOL, unless the wind blew it 180 degrees off the mark.

I think modeling has show Quads are NOT the magical antennas some thought they were ?

Nearly every maker of Quad antennas has bit the dust, that may tell you something ?

Read this http://www.w8ji.com/quad_cubical_quad.htm


 
« Last Edit: January 08, 2013, 09:17:21 AM by KA7NIQ » Logged

KZ4USA
Member

Posts: 151




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« Reply #17 on: June 12, 2015, 04:22:59 PM »

I don't like trap burning out when I run QRO
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G4AON
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Posts: 772




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« Reply #18 on: June 14, 2015, 09:45:19 AM »

Thirty years ago I had a TH3 MK3 tribander. On 20m, while displaying a good front to back ratio and a good match, it didn't have gain over a dipole on that band.

I note the specification of the later MK4 mentions an average gain and conveniently omits the claimed gain figures for each band.

The lack of gain on 20m is no real surprise, as on 20m there are 12 traps in series with the elements...

At least with trapless antennas there is a good prospect to model the design and in many cases the manufacturer publishes per band performance figures.

Dave
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NO9E
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Posts: 582




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« Reply #19 on: June 15, 2015, 09:07:55 AM »

Attempt to summarize, please add your (educated) comments.

Trapped yagis: relatively small, power restriction, traps fail in some brands and not in others, lower BW and F/B, inexpensive because of paid for design, not sure about trap losses (see W8JI).

Trapless yagi: more elements but each lighter, wide BW and good F/B if well designed, low maintenance cost, no power restriction

StepIR: perfect SWR, relatively light for multiband performance, mechanical problems for many, no instant QSY

Quad: good deal if 2 el, no power limit, 3-D structure, unwieldy with many elements

Hexbeam: Value leader by far

It seems that theoretical differences between competing designs are in single db most of the time. So large differences must be due to other factors like height and terrain.

Ignacy, NO9E
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KM1H
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Posts: 1277




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« Reply #20 on: June 15, 2015, 02:31:49 PM »

With Hy Gain the trap engineering was paid for 50 years ago. Look at the manuals going back to the TH-6DX and the same part numbers are still in use today from a dipole to TH-11. The JR antennas use smaller traps. I had a TH6DX for 5 years in the 60's at 90'; it was a killer on 15 and 20 but usually poor on 10 for DX. In later years after getting an "edumencation" I realized it was too high for a lot of DX paths at that time of the sunset cycle. I then added monobanders on rotating sidemounts for 10M and by 1985 I was all monobanders for 40-10M.
Note also the Hy Gains went from ratings of 1000W input to 1500W output and are now at 4000W PEP output. I doubt if many here will blow one!

OTOH their BN-86 balun is a piece of crap and is often the reason for poor antenna performance, I blew two of them at 1200W before winding a coax choke......decades before common mode raised its ugly head.

The only noticeable feature I hear about the StepIR is failures in the motors.


The Cushcraft A3 and A4 have excellent reputations also but I never cared much for Mosley performance based upon many installations for others vs the other brands.

I do have a complete TH6-DXX I got real cheap that Id like to put on a 40-50' tower for the vintage AM gear and convert to a TH-11 in the process of a full rebuild. Also have a complete TA-33 freebie I gave to a new ham and waiting for him to pick it up and follow my overhaul instructions. Somewhere in the pile out back is an ATB-34 and a TB-7, might be remains by now as Ive used the aluminum for something else.

Carl
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KB0IXM
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Posts: 4




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« Reply #21 on: June 16, 2015, 09:04:27 AM »

I've got a TH11DX made by Hygain before they were bought out and I wouldn't trade it for a StepIR or Force 12 period.  To each his own.  I know it works and it works well.
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W6GX
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Posts: 5292




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« Reply #22 on: June 16, 2015, 11:31:12 AM »

On-the-air tests showed little difference (if any) between my trapless antenna and my buddy's Mosley.  Ignacy listed out the pros/cons of each antenna design.  To each his own.

Trapless antennas are pretty easy to model and their performance is well-documented using EZNEC.  I have my own antenna modeled in EZNEC.  I'm curious if anyone has modeled a class trapped antenna such as the Mosley or TH-11?  If so I'd be interested to compare the performance.  I'm not married to a brand or a specific antenna design.  I want the best and the best wins my wallet.

73,
Jonathan W6GX
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W1VT
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Posts: 1906




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« Reply #23 on: June 16, 2015, 12:06:09 PM »

Adding traps to a Yagi typically reduces the turning radius--an distinct advantage in New England for hams who wish to keep trees on their property for wire antenna supports.  There are localities in which cutting down trees is a major hassle.

Zack W1VT
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KM1H
Member

Posts: 1277




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« Reply #24 on: June 16, 2015, 12:32:02 PM »

Trees and big branches fall on guy wires so the smart ham provides enough space no matter what the OL says!
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