Re: 23cm Yagis

Christopher Bartram <cbartram@...>

I've spent quite a lot of time designing yagis for my own use as it's an area that interests me. I've been considering publishing my current design, which according to simulation, at 1296 achieves ~20dBd on a 4m boom with just 42 elements. It has excellent performance re unwanted responses, but I need to make measurements of it in the real world, particularly regarding Sun, and cold sky/ground noise. These will provide more useful information than attempts to measure gain on any antenna range that I have access to.

Mike, G3JVL, designed his loop yagis in the 1970s. At that time I used them on both 70 and 23, but I don't now! Since then, there has been a serious revolution in amateur yagi design, starting with the work of Gunter, DL6WU, and continued by a host of others since. There's a lot of good information on DL6WU's designs, and some of the work that has sprung from them on GM3SEK's website, which is, as usual a fount of good sense. Incidentally, the Wimo 44ele antenna (and I presume others in that range) seems to be a pretty well unaltered DL6WU design.

Another source of good designs is G4CQM's website. His designs are generally pretty reliable, but I suspect more work is needed vis-a-vis the feed structures he suggests at 1.3GHz.

Vy 73



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