The G3TXQ Broadband Hexbeam Kit....... by Ant MW0JZE



K800_SNV35053

The G3TXQ Broadband Hexagonal Beam

(above image at M0OXO QTH)

NEW STYLE AIR COAXIAL ALL ALUMINIUM

CENTRE-POST NOW IN PRODUCTION

 

(Click image above for MW0JZE Hexbeam Site)

 

This antenna surely has to be one of the most talked about antennas over the past eighteen months or so. I started looking into buying one of these back in the spring of 2007 and at the time the ONLY commercial version was from Traffie Technology on www.hexbeam.com from the USA. Although the quality is of high standard it was out of my price range at over $1100 USD plus shipping and import tax so I decided not to buy one. A few months later I mentioned to an amateur radio op friend of mine that I was looking for a cheaper alternative and he informed me of the yahoo groups Hexbeam forum. This a forum run by Hexbeam enthusiasts from all four corners of the globe. You can find the forum on Yahoo Groups


 

In the Autumn of 2007 a new version of Hexbeam was being designed by Steve Hunt G3TXQ an avid home brewer and antenna modeler! This version used the same basic structure that the Traffie or “Classic version” uses but the element lay out is different. From above the classic version looks like an M over a W While the new G3TXQ broad band version looks like a M over a U.


CLICK IMAGE BELOW for you tube clips on how to build this antenna


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Steve’s website is one of the most informative websites on the web for explaining all the theory behind the new broadband version of Hexbeam and he also explains the theory behind the classic as to compare the two different but similar designs. If you are like both Steve and I a keen home brewer then you must pay a visit to Leo K4KIO website at www.k4kio.com. Leo explains how to build your own G3TXQ broadband Hexbeam, there are lots of measurements and plenty of photos for those hard to explain procedures, it is all very easy to follow! I will make no attempt to emulate either Steve or Leo's site as the work that these two Hexbeam stalwarts have produced is outstanding and deserves full credit, well done both!

 

 

This brings me to the spring of 2009. I am a member of the Strumblehead DX and Contest Group and we had been given permission to activate Ramsey island EU-124 off the west coast of Wales during the IOTA weekend.  I had been given the task of producing two lightweight multiband antennas for this trip, enter the G3TXQ Heaxbeam!

 

Click here for MW0JZE Hexbeam Site

 

The Hexbeam is an antenna design that has been around for quite a number of years, first produced commercially by Mike Traffie from www.hexbeam.com this is what many refer to as the "Classic Hexbeam" This has a turning radius of approx 9' 6" or 2.9m and covers 20, 17, 15, 12 and 10m

 

 

In 2008 Steve G3TXQ redesigned the Hexbeam making it more broadband, in fact you will not need a tuner at all if everything is assembled correctly. This antenna is referred to as the "G3TXQ Broad Band Hexagonal Beam" and this is the antenna referred to trough out this website. The turning Radius has been increased to 10' 9" or 3.28m, this is a small price to pay for an improvement in bandwidth. EZ-NEC+ Modelled SWR, Gain and FB at 30 feet above clear open ground

 

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Band
Band Width KHz
Gain dBd Add 2.15 for dBi
FB dB
20M
350
3.8
22
17M
100
3.2
19
15M
450
3.5
16
12M
100
3
13
10M
1400
3.6
16
6M
1400
2.7
11



The Hub

This is the centre of the antenna, the centre post that the wire elements connect to sits on the top and the stub mast sits below. This is also where the six fibreglass spreaders are attached. The hub is made of a 30cm sq aluminium (some builders have used wood or even thick plastic) sheet cut into a hexagonal shape with two steel tube clamps fitted (one top and one bottom) to support the centre post and stub mast in the centre of the hexagonal. 12 U bolts are used to fix the spreaders to the hub, two for each spreader.


The Centre Post

The most complex part of the antenna, some builders place the coax on the out side and weather proof it, this is fine but sooner or later you will have to replace the coax as weather will take its toll in the end. This is inexpensive so no big deal and it does the job. You can go to the extreme and house the coax inside, this can be fiddly and time consuming unless you have a crafty way of doing it! There can be up to six bands on most G3TXQ broadband hexbeams and each band will need a centre and a braid connection so 12 feed points in all, two per band. This is where the wire elements attach to. There is also a fixing point attached to the top of this post for the spreaders support cords to be attached to.



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The Spreaders

Six spreaders are used to form the hexagonal shape. The ends are bent towards the centre post and attached to it via support cords fixed to the top of the post, this gives it it's up-side down umbrella shape. D-loops or cable ties are generally used as fixing points on each spreader for the wire elements to be attached to, this forms the shape of the elements and keeps them slightly taught!


Wire Elements

The wire elements are generally made from 14 or 16swg bare copper stranded wire with terminal eyes soldered on the ends. There are two driven elements per band and one reflector. Configuration is driven, spacer, reflector, spacer and driven. The spacing's are made of Dacron cord or similar non-conductive material and fixed to the terminal ends by simple means such as tying knot if you so wish! Each band has a wire element and they are threaded trough the d-loops, cable ties or any other non-conductive method you can design or think of to attached them to the spreaders. Assembly is done by attaching one end of the element to the one feed point terminal and going complete circle, or hex with the other end until you arrive back at the other feed point. Repeat for all other bands!!


What do you Get?

 

  1. Baseplate with 6mm plate and large 48mm top and bottom alloy flange

  2. 35mm OD Aluminium Air Coax Centre-Post (No Coax) SO239 or N-Type connector on request

  3. Heavy duty fibreglass spreader set with wire element fixings

  4. Six wire elements for 20, 17, 15, 12, 10 and 6M


Each G3TXQ Broadband Hexagonal Beam is made to order, please allow two to three weeks after payment has been made for delivery. I only take payment when I am ready to start making your Hex and a first come first served policy is used.

 

 

Assembly time 1 hour approx, I can do it in half an hour, so will you once you have seen it built. Each antenna is designed to be assembled quickly, this makes it ideal for field days, IOTA, portable days out or DX-Peditions!

 

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above - MW0JZE Hexbeam @ M0OXO

 

The Hexbeam works best at heights around 35ft or more but it gives a good account of itself even at 20ft – particularly if it isn’t pointing towards any close obstructions. You will see a marked reduction in SWR when raised to a reasonable height and away from nearby obstructions such as buildings. Remember that this beam is broad-banded so the SWR will remain quite low across each band – and well within range of most built-in antenna tuners in modern transceivers.

Heavy Duty Hexbeam Hub

 

Heavy duty centre hub made from 6mm aluminium plate and two tube clamps as flanges. Aluminium tubes are fitted to protect the spreaders from being crushed if the u-bolts were to be over tightened. This is also handy if you were to use the antennas on portable events such as field days, no time wasted tightening u-bolts up, just slide the spreaders in and away you go! Centre post/stub mast is secured with two M8 x 75mm stainless machine screws with stainless nuts and washers, one top and one bottom for extra strength.

 

 

K800_SNV35058
(above - MW0JZE's build at M0OXO QTH)

 

Prices

 

6 Band G3TXQ Broadband Hexbeam, large TOP and BOTTOM flange £450 GBP

Balun Option 1 click here for details

6 FB31 1020 Beads on feedline FREE OF CHARGE

Balun Option 2 click here for details

FT240 43 Torriod with 8 turns of RG142 sealed £50 GBP

Shipping price will be given on request.

 

Hardware

 
  • 6mm Aluminium plate 30cm sq cut into hexagonal shape
  • Two heavy duty tube clamps as flanges, cast iron.
  • 12 x 35mm u-bolts (zinc) with stainless steel ny-lock nuts and washers
  • 6 x 3.5 inch 1” 1/8th OD aluminium tubes
  • 2 x 8M x 75mm stainless steel machine screws with stainless ny-lock nuts and washers
  •  



contact-ant

 

Thanks, Ant........

 

Click here for MW0JZE Hexbeam site

 

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