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My 30/40 Meter Full Size Hexbeam
Category: N6AQ Ham Stories and Articles Author: N6AQ Date: 6 days ago Comments: 0

How far can you go with wires?

Around the time the HexBeam came onto the scene I have played with the idea of a full size 30/40 meter HexBeam. I was one of the first folks to order one of the DX Engineering HexBeams that covered 10-20 meters and I was very impressed with the construction and performance. I do have to say one of the problems that I caused with the 10-20 HexBeam was that I put it on top of my 100′ tower and that was way to high. I noticed that my first hop was 1000 miles and overshot a lot of the stations that were closer.

I digress, using building and design concepts from the smaller HexBeam I just up-scaled everything including the DX Engineering spreader mount https://www.dxengineering.com/parts/dxe-hexx-1hbp.

I tried to use only the best parts that would last. I used copper clad hard drawn wire from the wireman (insulated) https://thewireman.com/product/antenna-wire-13-awg-copper-clad-steel-stranded-jacketed/

In this article I will lay out some of the lesson’ slearned when trying to build a massive antenna like this. Of course during my engineering phase of this project I did my research and found two other document 40 meter HexBeams at that time. One was located in 7 land and the other was my friend Danny in South Africa that has been running one for years. We would have numerous HexBeam to HexBeam contacts over the life of my Hexbeam which to came a tragic end in the Texas wether.

Look at the size of this thing.

Thats my son in the picture and he was very excited to help me with this project. Just as any other teenager would be on a beautiful day during summer break, LOLOL.

The fiberglass arms (Spreaders) ended up being approximately 24′ each to accomplish the proper spacing to apply the elements and to make it symmetrical for appearance. I obtained the spreaders from DX Engineering https://www.dxengineering.com/search?keyword=fiberglass&SortBy=BestKeywordMatch&SortOrder=Ascending. Each spreader had its own 550 UV resistant kevlar paracord tensioner that went to the top section of the center mast.

In the above picture you can see the center mast top cap that the spreader tensioner cord was attached to. It was easier to make individual cords for each spreader arm to ensure symmetric alignment. This picture also shows the coax attachment points to feed the individual elements, these attachment points slid over the center mast and were held in place with friction and the stiffness of the RG-218 coax.

You will need a coax attachment point for each band you plan on putting on the antenna. I had 30/40 meters so I had two.

For those of you that do not know this, for electrical connections you should try to use brass hardware for corrosion resistance, that’s why you see a lot of brass items being used on water vessels.

The brass does not play a role in conductivity since the eyelets of the coax and wire half’s will be directly touching each other. I highly suggest that your projects you include corrosion control mitigation. The easiest and best way I have found to deal with corrosion on electrical connections to include aluminum antennas is NoLox (electrical grease) and Plastidip. Plastidip will form a protective layer over the electrical connection keeping it corrosion free for decades.

Putting this thing together.

The first problem that came to mind was how to stabilize this antenna during construction? I knew that a jig was the only way to go so I took the extra time and constructed a stand that would securely hold the antenna in place and still make it easy enough to move around. In the picture above you see my solution, simple and crude but worked. 

During the mock up I made sure that everything would align and fit. I could not have been happier with the results. The DX Engineering spreader mount worked like a charm for this application.

Building this size of an antenna comes with considerations, I am no engineer but with more mass comes more strain that needs to be considered. I put the actual spreader inside of a larger to help with the potential forces exerted on the smaller spreader arm. This also helped distribute the compression load of the u-bolts in the picture.

DO NOT DO THIS!

DO NOT DO THIS, I attribute this construction technique to the direct loss and destruction of this antenna. the proper way to do this is to slot the fiberglass and use compression clamps to secure the elements. Upon examination of the failed element it was broken exactly along the bolt line. Once one of the elements failed in 80mph wind gusts the rest failed and collapsed like a house of cards.

The above image provides a better idea of wire attachment points. The shorter of the two antennas is 30 meters and would go on the bottom feed point and the 40 meter element would go on the top feed point connection. Please keep in mind when feeding this antenna you would do it from the bottom and put a choke at the coax connection point, this can be coax turns or like mine I opted to use Ferrite’s that slipped over the coax sleeve.

Getting it in the Air!

I installed and erected a guyed Rohn45G tower that was 60′ tall and guyed it at the top into secure rebar enforced concrete blocks.

After completing the assembly and inspection of the antenna I determined the date when help would be available and scheduled a crane service for the installation. The antenna itself on weighed about 70 pounds which let me use a moderate strength rotor Yaesu G-1000DXA (https://www.gigaparts.com/yaesu-g-1000dxa.html)

Due to the size of the antenna and the amount of scrub oak trees surrounding the antenna site it was deemed to get a small crane to lift the antenna in place. This approach worked exceptionally well and and was very affordable.

More 30/40 Meter Hex Beam Pictures

Please take the time to scroll through the pictures below.

But how did it work?

On 30 meters it worked better than expected and with the limitations on the band you had to be careful with ERP and such but it worked like a champed logging me plenty of stations.

On 40 meters at legal limit this thing was the bomb! 100% regular contacts with Danny in South Africa and Ferry in YB0 land. This antenna produced great report from around the globe. My most noteworthy contact was first call into a massive pileup to Reunion Island, the DX station came back to me immediately as asked my location. I responded with San Antonio Texas, he sounded very surprised and told me that he thought I was on the island with him because of my 59+40 signal.

 

In conclusion......

I had a great time designing, constructing and erecting this antenna and it lasted almost two years. It provided me with hundreds of great contacts and for a short time I had some bragging rights since there were a handful of HexBeams this size in operation around the globe.

The real question is would I do it again knowing what I know now and the answer is a resounding YES!

In all honesty after considering all the expenses involved I could have purchased a 3 element 40 meter beam which would have held up to the harsh Texas weather.

This was a great project and I hope other hams find this useful, if you have an questions please leave a reply in the comment section.

N6AQ

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AUDIO

KL7RA Alaska. From DXNews.com
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