It was more than a long time ago.
At Yugi-higashi amateur radio club, we decided to “make an antenna together,” and we chose this “Hentena” because it is a 430MHz antenna that can be made in one day without special materials, has good reproducibility, and has decent performance.
The Yukihigashi area is a bit too wide for round QSOs using only a whip antenna on a handheld radio, (the straight-line distance is not that great, but there are many housing complexes where “walls” tend to form) We decided to make one together because it can be put out on the balcony and can emit vertically polarized waves without the need for a troublesome earth.
Needless to say, this “Hentena” is the most amateur-like of amateur radio antennas. It was Okubo OM, JH1FCZ, who introduced this antenna in the magazine “Radio no Seisaku” around 1975.
Unfortunately, he passed away last summer, but I enjoyed reading every issue of his magazine “Fancy Crazy Zippy” until it ceased publication, and he was like a mentor in distance learning how to make my own radio.
The “how to make” is easy, so the key is “what to make it from.” 430MHz is small, so perhaps the charm of making this antenna is making it with whatever materials are available at the time. This time, I used a scrap of V-wire (1.6mm) for the element. The support material is a scrap of VP13. But if I used IV wire as it is and made a rectangle 35cm long x 11cm wide, it would be floppy.
First, I stripped off the insulation of the IV wire, prepared 2m and folded it in half to make a hairpin shape. Find a thin, round fulcrum that will not move even if I put some weight on it, and hook the copper wire on it.
Put the two copper wires on one end into the chuck of an electric drill and tighten it. Hold this down and apply tension while rotating the drill at a slow speed. Stop it at the appropriate point and it’s done.
Just twisting two strands together not only makes it more resistant to bending, it also eliminates any kinks in the copper wire, and you can get a nice straight piece. It still looks like this even after leaving it in the garden for 12 years. The SWR is low and it’s still usable.
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