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 Tuning A Hexbeam 
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Post Tuning A Hexbeam
Hi All,

2 years ago I bought a Hexbeam from SP7IDX, due to illness and other problems I have only just managed to assemble it and put on the mast.

At the moment it is only 10feet above the ground, sitting 12" above a terracotta tile roof.

Before putting it its final height of 25 feet above the ground, I thought I would check the SWR.

On 20m the SWR is around 2.3 across the whole band.
On 17m the SWR is around 2 across the whole band
On 15m the SWR is around 2 - 2.5 across the band
On 12m the SWR is around 2 across the whole band
On 10m the SWR is around 1.5 across the SSB portion of the band
On 6m the SWR is over 3 across the whole band

This doesn't seem right but never having used a Hexbeam before, I am wondering if the height above ground and the roof is affecting things. I have noticed that the weather seems to have an effect. The warmer it is the better the SWR is but not by a lot.

For practical reasons, I can't raise the beam up any higher to test it for about 10 days.

So the question I need answered is, am what I am seeing 'normal' and will the SWR improve when I do get it up higher. If what I am seeing is not 'normal', what is the best way of tuning it? I don't want to start messing with the length of the elements, the are all cut so size by SP7IDX and according to my reading reviews of his design, work well out of the box. I have checked very carefully and I am 99% certain that I have assembled everything correctly.

Any ideas and help gratefully accepted.

Tim


Mon Sep 10, 2018 9:29 am
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 Tuning A Hexbeam 
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Post Re: Tuning A Hexbeam
Hi Tim,
I haven't had any experience with the Hex, but height above ground usually affects the feedpoint impedance/SWR.. This is worth a read: http://karinya.net/g3txq/hexbeam/tuning/

Good Luck
Dave.

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Mon Sep 10, 2018 10:39 am
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 Tuning A Hexbeam 
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Post Re: Tuning A Hexbeam
Thanks Dave, as you suggest, Steve's article does make for interesting reading and confirms what I thought about the height above ground and the roof. Initially I was a bit disappointed with the results but until I actually get it is the air at the proposed height, it isn't worth doing anything.

Tim


Mon Sep 10, 2018 11:14 am
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 Tuning A Hexbeam 
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Post Re: Tuning A Hexbeam
I had a hex beam do not prune or fold anything till its up in the air, then I'd look at the readings.

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Mon Sep 10, 2018 11:41 am
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 Tuning A Hexbeam 
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Post Re: Tuning A Hexbeam
My G3TXQ designed built by Anth MW0JZE has been up in the air for 4 years.
SWR is as good today as it was on the day my Hexbeam was erected at 40 feet ish.
I know it does not help your problem Tim but maybe food for thought.
73
Keith.

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Mon Sep 10, 2018 12:00 pm
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 Tuning A Hexbeam 
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Post Re: Tuning A Hexbeam
159 reviews with an average rating off 4.9 out off 5 for this particular version.

would have a read thru some off the reviews see if you can find anything relating to swr issues, failing that drop the chap a message am sure he will keep you right if not too buys buidling them ?!

https://www.eham.net/reviews/detail/10554

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QRV on 10mtrs ssb.


Mon Sep 10, 2018 1:48 pm
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 Tuning A Hexbeam 
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Post Re: Tuning A Hexbeam
Thanks for all the thoughts, I am pretty sure that when it's up in the air it will improve dramatically.

I have read nearly all the Eham reviews and they are the main reason I ordered from Waldi, the main problem people seem to have is not the quality or performance but very long delivery times. Mine did take three months to arrive, just my problems here prevented my from getting it built. I also bought an Alpha Spid rotator from Waldi, that was superfast delivery, 5 days from order to receipt but again that was 2 years ago.

Tim


Mon Sep 10, 2018 2:44 pm
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 Tuning A Hexbeam 
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Post Re: Tuning A Hexbeam
10ft above ground isn't very high all all, I suspect the ground is influencing the figures. Here's what you should be getting:
http://sp7idx-hexbeam.eu/hexbeam/perfor ... teristics/

Mine's down at the moment but I get great SWR on all bands, a little higher on 1 or 2 bands (12m I think) but only 1.6-1.8. As others have said, you can't tune it, all the elements are pre-cut.


Mon Sep 10, 2018 2:50 pm
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 Tuning A Hexbeam 
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Post Re: Tuning A Hexbeam
Funny enough just about to order my own one. was looking for a used one but guess they are so good folks are just hanging onto them !

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Icom IC7300 / Kenwood TR751e
5/8 wave 10mtr vertical / 80-10mtr OCF dipole.
Behringer xm8500 mic ( IC7300 ) Datong ASP ( TR751e )
Ameritron als600x s/s linear

QRV on 10mtrs ssb.


Mon Sep 10, 2018 4:20 pm
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 Tuning A Hexbeam 
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Post Re: Tuning A Hexbeam
Have to say that I am very impressed with the build quality of the SP7IDX version. Everything is so well labelled that a manual is not needed to put it together.

I did mine in about 3 1/2 hours from start to finish. Not having enough space on the ground I did it sitting on a sloping roof which, because of the corrugated tiles, is very uncomfortable and it was about 28C all afternoon whilst I was doing it, add to that my age, 71 and the fact that I don't have as much strength or stamina as I used to, I would say that the average person should find it easy to assemble in less than 2 hours.

As I said, I researched every Eham review and others and it was a tossup between Ant's offering and Waldi, I chose Waldi because it was priced in Euros which made it easier for me to pay him.

Tim


Mon Sep 10, 2018 6:19 pm
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 Tuning A Hexbeam 
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Post Re: Tuning A Hexbeam
Thanks Tim appreciate your advice and hope you get the swr sorted on yours and have much joy with your new purchase !

Please update thread with a pic off your antenna once up in the air if you will.

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Icom IC7300 / Kenwood TR751e
5/8 wave 10mtr vertical / 80-10mtr OCF dipole.
Behringer xm8500 mic ( IC7300 ) Datong ASP ( TR751e )
Ameritron als600x s/s linear

QRV on 10mtrs ssb.


Mon Sep 10, 2018 6:30 pm
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 Tuning A Hexbeam 
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Post Re: Tuning A Hexbeam
Just put mine back up. SWR is low 1:1 on 20/17/15, resonance is slightly high on 12m just above 25MHz so in-band 12m SWR is 1.4, 10m is 1.7 but pretty flat right across the band.

I'd forgot how good these aerials are, solar flux is rock-bottom but first two QSOs on 17m were YB0s :D


Sun Sep 16, 2018 2:41 pm
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