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 Yagi Droop how much is acceptable ? 
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Post Yagi Droop how much is acceptable ?
I have a long 60 odd element 1296mhz yagi which has droop at both ends.

Is there a calculation for acceptable end droop?

Mark

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Sun Aug 30, 2020 1:30 pm
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 Yagi Droop how much is acceptable ? 
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Post Re: Yagi Droop how much is acceptable ?
Hi Mark

Don't know of any calculator, but I do remember reading something by SM5BSZ on the "Moon-net Reflector" some years back along the lines of seeing 1dB loss with 0.25WL variation along the boom if any help.

I had some sag on my 67el, but have added additional myself bracing to get it level.

73 Kelvin

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Sun Aug 30, 2020 7:02 pm
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 Yagi Droop how much is acceptable ? 
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Post Re: Yagi Droop how much is acceptable ?
Ok, thanks for the reply.

It appears this is exactly the same yagi maybe.

The yagi in question is the Wimo 2367: 67 element ( 61 really as reflector has 8 of them ) 1296MHz.

The rear droops almost 100mm and the front about the same.

How have you reinforced yours?
Does it affect the pattern?

I was outside today attempting to use some string and a plastic tube to act as a center support tied to both ends but this was a failure.

I was thinking of just placing the whole boom on top of a larger boom.

Mark

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Sun Aug 30, 2020 8:24 pm
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 Yagi Droop how much is acceptable ? 
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Post Re: Yagi Droop how much is acceptable ?
Yes same aerial here.

I ended up using some fibreglass tubeing I already had as didn't want to tempt any additional metal interaction. Certainly not good to put any form of stub mast and cord support as totally important to not have any metal through the element line.

When assembled there wasn't any sag on mine, but feeding it direct with Ecoflex 15 it certainly pulled the back down.
Good luck.

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Sun Aug 30, 2020 9:14 pm
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 Yagi Droop how much is acceptable ? 
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Post Re: Yagi Droop how much is acceptable ?
Mine was also ok until I connected some ultraflex 10, but also the other end sagged as well.

I take it you just tape'd the fibreglass tubing on top?

I think I may just put up with the sag until I finish making a decent boom'd one as the supports are bending aswell!

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Sat Sep 05, 2020 6:45 pm
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 Yagi Droop how much is acceptable ? 
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Post Re: Yagi Droop how much is acceptable ?
I did parallel it on top initially, but then found some really strong fibreglass tubing in the garage roof so ended mounting it below with a bracket off the stub mast.

It supports the Eco15 horizontal and away from the aerial then up to the connector rather than along the boom. Ended up doing the same physical job but also stopped chance of any rain collection causing detuning.

There's a pic on my qrz listing that should explain better ;)

73

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Sun Sep 06, 2020 12:04 pm
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 Yagi Droop how much is acceptable ? 
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Post Re: Yagi Droop how much is acceptable ?
How about using a support wire instead?

It adds very little weight but will hold up the sagging ends well.

Like this commercial example >>> https://www.antennas-amplifiers.com/2-meter-11-element-low-noise-antenna-144mhz-yagi


73, Mark...

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Thu Sep 17, 2020 6:28 pm
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 Yagi Droop how much is acceptable ? 
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Post Re: Yagi Droop how much is acceptable ?
I have had a go at a support wire like i have on my M2 5WL. But there is no pole to attach the support to as it ends about 50cm below the boom.
The boom is also so badly designed that any tension would bend the boom sideways.

Basically the Wimo 23cm 67ele is a shoddly made antenna which shouldnt have been allowed to go on sale.
I have seen TV antennas that are better made.
Almost as bad as Vine Yagis. But not quite.
Thats another story...

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Thu Sep 17, 2020 10:51 pm
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 Yagi Droop how much is acceptable ? 
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Post Re: Yagi Droop how much is acceptable ?
I’m not a fan of the wimo 23cms yagis ....I had the 67 element one up here and it soon bent out of shape once the winds from the North Sea hit it .

Now using a 36 element antenna amplifiers yagi on a 3m boom .....no problems with it ...but obviously shorter than the wimo was

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Tue Sep 22, 2020 8:54 am
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 Yagi Droop how much is acceptable ? 
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Post Re: Yagi Droop how much is acceptable ?
I've 67 elements here on 13cm and 23cm.
No mechanical issues with either although I suspect I need to look at the dipole on the 23cm unit.

I've also a few Eagle Antennas. 2M, 4M, 6M, Yagis, two 4/6 dual bands and a 10M Moxon.
No issues and all have been working well for many years.

Cheers

Tony

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Tue Sep 22, 2020 10:37 am
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