[TowerTalk] [Towertalk] W1JR Yagis in Winter 98 ComQuart

[James R. Duffey]

Joe Reisert, W1JR, presents several nice Yagi designs in the Winter 98
Communications Quarterly. He also has some good comments to make on Yagi
design and construction in general.

The designs have 50 Ohm feedpoint so matching is trivial-just hook up a
choke balun to the split driven element, adjust the driven element length
for resonance and go.

They have large bandwidth, about 5%, and good front to rear ratio over the
rear hemisphere, >20dB. The gain is modest at 5 dB(dipole) for the 3
element and 6 dB(dipole) for the 4 element. This is somewhat lower than
with designs optimized solely for gain. The high feedpoint impedance,
however, makes it much easier to achieve the design gain. Many of the
designs optimized for high gain have low feedpoint impedances which make
matching difficult and tends to increase resistive losses.

I intend to put up a few fixed wire beams this spring and summer. These
designs seem ideally suited to that application. I will keep you posted as
to how it all comes out.

Although the price of ComQuart is pretty steep, $9.95 per issue, this may
be worth the price.

If you are looking at new Yagi designs you may wish to try these.

The article has much the same flavor as his old Ham Radio VHF/UHF columns.
- Duffey KK6MC/5

James R. Duffey               <ji3m@maxwell.com>     (505) 764-3143
Maxwell Technologies Inc.     http://www.maxwell.com/
2501 Yale Blvd SE Suite 300
Albuquerque, NM 87106-4200



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