During the committee on Sunday we discussed antennas for the shack and I think rightly decided on a OCF multiband as the base antenna. We also talked about a secondary HF antenna that we would build as well.
Well I was at the monthly meeting of the Richardson club last night and we had a presentation on an antenna type that I think we should consider for a club build, the broadband hex beam.
The basic specs of this type of antenna are very promissing for the current location. For instance, a 5 band antenna that covers 20M through 6M has a small horizontal foot print of only about 22 feet. A vertical elevation of only 3-4 feet and can work quite well even on 5-10 feet above ground level. It has the gain of a two element yagi.
Best of all the mechanical construction aspects would be pretty straight forward for us given the available tooling.
Anyway, not thinking it should be an immediate project, but something to consider after we get the basic stuff we discussed done.
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This kind perhaps ? http://www.hex-beam.com/
I’ve been looking at that for my home QTH. The center plate looks like a good HAAS mill project. And done once, it should be reproducible. If there’s interest, we might be able to do a group buy on the fiberglass poles, which seem to be a big chunk of the project cost.
Todd - K5SLR.
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Yep, that is one manufacturer. The guy who gave the presentation has his design in local production. He raised some good points about DIY on several aspects, including the center plate and how the fiberglass poles are mounted to it.
The HAAS could certainly do parts of the center plate, heck we could even do it on the Bridgeport fairly easily as well. Then there is some welding for the center post with the coaxial connections.
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Might be worth looking into as a group build. I’d love to hear about the concerns the presenter raised. I just completed the HAAS training. After the domino project, I may look into this. ( it was on my todo list already… )
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The model you linked to uses uclamps to attach the poles to the base plate which can cause cracking. A number of other approaches are used, but they all amount to providing more even pressure. The one that seems easiest is to use pipe that is large enough to go over the fiberglass post. You then split that pipe lengthwise and it provides some nice uniform clamping pressure.
Kind of like a large collect.