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 20m Hex beam 
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Post 20m Hex beam
Hi All.

I'm looking at a couple of winter antenna projects. One of which is to build a wire HEX configaration beam for 20m, if that makes sense????? Just wondered if anyone had attempted anything similiar or could give me any pointers. Was going to build a 20m moxon but lack of space dictates I need to come up with something smaller.

Dave M0WMX

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Mon Oct 14, 2013 2:27 pm
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 20m Hex beam 
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Post Re: 20m Hex beam
A Hexbeam is only 2ft narrower than a Moxon but the Moxon is a fair bit easier and cheaper to build as well as having the edge on performance.

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Mon Oct 14, 2013 4:13 pm
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 20m Hex beam 
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Post Re: 20m Hex beam
Thanks Conor. I've built several moxons in the past, so just fancied trying something different. Do you think the moxon edges the performance? Thanks for the reply.

Dave M0WMX

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Mon Oct 14, 2013 4:35 pm
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 20m Hex beam 
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Post Re: 20m Hex beam
Its a couple of dB up on forward gain but has better F/B and F/S which may or may not be important to you.

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Mon Oct 14, 2013 7:04 pm
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 20m Hex beam 
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Post Re: 20m Hex beam
Here are the comparative figures from EZNEC (all Free Space):

14.00MHz MoxGain=6.6dBi, HexGain=5.7dBi, MoxF/B=14.5dB, HexF/B=13.1dB
14.05MHz MoxGain=6.4dBi, HexGain=5.5dBi, MoxF/B=18.5dB, HexF/B=16.3dB
14.10MHz MoxGain=6.2dBi, HexGain=5.3dBi, MoxF/B=25.0dB, HexF/B=20.4dB
14.15MHz MoxGain=6.0dBi, HexGain=5.1dBi, MoxF/B=39.5dB, HexF/B=24.0dB
14.20MHz MoxGain=5.9dBi, HexGain=4.9dBi, MoxF/B=25.4dB, HexF/B=22.4dB
14.25MHz MoxGain=5.7dBi, HexGain=4.7dBi, MoxF/B=20.1dB, HexF/B=18.9dB
14.30MHz MoxGain=5.6dBi, HexGain=4.5dBi, MoxF/B=17.1dB, HexF/B=16.2dB
14.35MHz MoxGain=5.4dBi, HexGain=4.4dBi, MoxF/B=15.0dB, HexF/B=14.2dB

The Moxon Gain advantage varies from 0.9dB to 1.1dB across the band. The Moxon's peak F/B is very high, but it holds over only a relatively narrow bandwidth - it has dropped by 14dB, 50kHz either side of the design frequency.

Steve G3TXQ


Mon Oct 14, 2013 7:22 pm
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 20m Hex beam 
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Post Re: 20m Hex beam
Thanks Steve. Looks like its back to the drawing board. I really dont have the space for moxon on 20m, I might experiment puting a V in the centre, HEX beam style, and go from there.

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Tue Oct 15, 2013 7:22 am
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 20m Hex beam 
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Post Re: 20m Hex beam
Just discovered the VK2ABQ beam, the antenna Les Moxon based his antenna on. Something else to throw into the mix.

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Tue Oct 15, 2013 3:35 pm
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 20m Hex beam 
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Post Re: 20m Hex beam
The VK2ABQ should work out at 5 metres wide, just over 16ft, funnily enough I've been looking at building one of those rather than a Cobweb as there's not a lot of room on the side of the house between the next door neighbours fence and my place... 8ft either side of the centre line might be do-able though.

I was looking online but there's not much in the way of precise dimensions, plus a few teasers indicating it will tolerate nested bands but then a bit vague about interconnecting for a single feed to the antenna... out with the analyser.

Cheers, Dave.


Tue Oct 15, 2013 4:44 pm
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 20m Hex beam 
Silent Key

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Post Re: 20m Hex beam
The VK2ABQ turn radius works out just over 13ft, compared to 10.7ft for a hexbeam and about 6ft for a cobweb. The gain is less than a hexbeam, and the typical feedpoint impedance lies between 70 Ohms and 100 Ohms.

If you can afford the turn radius of a VK2ABQ, you can probably fit in a Moxon, which has superior performance and a good 50 Ohm match.



Steve G3TXQ


Tue Oct 15, 2013 5:01 pm
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 20m Hex beam 
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Post Re: 20m Hex beam
I love my Moxon Steve but on 20 it's 24 ft wide and the modest turning radius required misses out that to an unimpressed neighbour the antenna has a massive wingspan.

The Cobweb at just over 8ft per side is the sensible foot in the door but it would be so lovely to reduce the QRM from southern Europe.

Cheers, Dave.


Tue Oct 15, 2013 7:22 pm
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 20m Hex beam 
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Post Re: 20m Hex beam
Dave, if you haven't used a cobweb before, I think you'll be mighty pleased with how it performs. Spare a thought for the hard done to mobilers, splatter is just part of life's rich tapestry :shock:

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Tue Oct 15, 2013 8:17 pm
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 20m Hex beam 
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Post Re: 20m Hex beam
I think I'll build another moxon for 15m, just to ease my way back in, I still have the boom and element supports assembled, just need some ebay fishing poles.

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Wed Oct 16, 2013 10:59 am
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 20m Hex beam 
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Post Re: 20m Hex beam
Put up a vertical and spend a bit of time on the Radials.been using VK2ABQs for years,easy to make and perform well.


Sun Oct 20, 2013 1:24 pm
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 20m Hex beam 
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Seems like i"m changing my mind daily with potential projects. Looking in to quad's as well. I could end up with 3 or 4 antenna's on the go. :banghead: :banghead: :banghead:

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Sun Oct 20, 2013 5:39 pm
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 20m Hex beam 
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Post Re: 20m Hex beam
Well, ended up making another Moxon for 15m which went up last night. First call on the beam went out to N3EON who gave me a genuine 5-9. Very happy.

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Thu Oct 31, 2013 3:28 pm
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