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G4ZU Bird/Spiderbeam
- Thread starter RickC.
- Start date
I almost bought one. Had my finger on the 'buy' trigger. The thing is, that they are selling for a lot more money than they are worth. In the sense that the materials and labor involved don't justify the cost. $600 is a bit steep for what you get.
If the claims about the gain and usable freq's are true - it seems quite desirable. I'd like to see an American company make these at $225 and sell a lot of them. I'd like to hear what Hams have to say about it after they use one for a year. That should clear out the truth from the claims...
If the claims about the gain and usable freq's are true - it seems quite desirable. I'd like to see an American company make these at $225 and sell a lot of them. I'd like to hear what Hams have to say about it after they use one for a year. That should clear out the truth from the claims...
My thoughts exactly, Rob, about the cost.
If you go to the Yahoo Spiderbeam group, there are guys who are homebrewing them from fiberglass fishing rods. I happen to have four 20' rods from other projects which would be too flimsy at the ends to build a replica of the commercial beam, but they'd be OK to build G4ZU's original design, which for a monoband 20m version would be only 24' front to back rather than 34' (or whatever the Spiderbeam is).
For a monoband beam though, W4RNL's analysis of it shows it to be only slightly ahead of a normal 2 element yagi, though it would be lighter. As you may have concluded from your antenna projects though, a 2 element yagi is a much better antenna than most would give it credit for. I had never used one until I built one a couple of years ago (OK, it was 2 elements on 20, 2 on 10 with a common feed, beta match) and even only up 33 feet it surprised me.
Still, the G4ZU design is interesting. I'm not quite Jones'n for it enough to build it just yet, especially since that fellow was good enough the send me the Giza beam article I hadn't seen since 1983, but I'm still mulling it over.
I'd be interested in a longer-term evaulation of the Spiderbeam too, preferably from someone who's used beam antennas long enough to know what they should be able to do. The eham.net reviews are good, but how many people are going to spend that kind of cash on an antenna and then say it's not good? Comparison to a monoband yagi wouldn't be fair, but to a trap tri-bander would be apples-to-apples, I think.
The most interesting thing to me about that antenna is the balun and multiband parallel feed. I had to read through it a few times to grasp just what they were doing with that (the parallel feedlines from the balun and the heatshrink), but it makes sense. It's just a happy accident that those bent elements raise the radiation resistance close to 50 ohms.
Rick
If you go to the Yahoo Spiderbeam group, there are guys who are homebrewing them from fiberglass fishing rods. I happen to have four 20' rods from other projects which would be too flimsy at the ends to build a replica of the commercial beam, but they'd be OK to build G4ZU's original design, which for a monoband 20m version would be only 24' front to back rather than 34' (or whatever the Spiderbeam is).
For a monoband beam though, W4RNL's analysis of it shows it to be only slightly ahead of a normal 2 element yagi, though it would be lighter. As you may have concluded from your antenna projects though, a 2 element yagi is a much better antenna than most would give it credit for. I had never used one until I built one a couple of years ago (OK, it was 2 elements on 20, 2 on 10 with a common feed, beta match) and even only up 33 feet it surprised me.
Still, the G4ZU design is interesting. I'm not quite Jones'n for it enough to build it just yet, especially since that fellow was good enough the send me the Giza beam article I hadn't seen since 1983, but I'm still mulling it over.
I'd be interested in a longer-term evaulation of the Spiderbeam too, preferably from someone who's used beam antennas long enough to know what they should be able to do. The eham.net reviews are good, but how many people are going to spend that kind of cash on an antenna and then say it's not good? Comparison to a monoband yagi wouldn't be fair, but to a trap tri-bander would be apples-to-apples, I think.
The most interesting thing to me about that antenna is the balun and multiband parallel feed. I had to read through it a few times to grasp just what they were doing with that (the parallel feedlines from the balun and the heatshrink), but it makes sense. It's just a happy accident that those bent elements raise the radiation resistance close to 50 ohms.
Rick
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I've considered building either the spiderbeam or hexbeam several times but never have done it. What I would really like to come up with is a way to make the thing easily portable - something you could build in a manner that would make it easy to take down and put back together without having to re-measure. I'm sure I could come up with a way if I just took the time to figure it out.
Yeah, it looks like the Spiderbeam concept would be easier to use portable and would be easier to get up in the air than the Hexbeam, though it's a lot bigger. I guess that's where all the velcro, etc., comes in.
That's a lot of wire to mess with on a portable antenna though, if you put all 5 bands on it!
Rick
That's a lot of wire to mess with on a portable antenna though, if you put all 5 bands on it!
Rick
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