The hairpin length will vary with the antenna impedance so you cannot just
scale it down. I used hairpin matches for years and I made them out of
3/16 or 1/4 diameter aluminum and just screwed them to the feed point
screws. When using a hairpin you need to shorted the driven element. To
adjust the antenna you have to play with both the hairpin and driven
element lengths. Currently I build yagis with a 50 ohm impedance. No
match is needed. It is much easier to adjust and there are no matching
losses.
John KK9A
To: 6m <50mhz@mailman.qth.net>, antennas <antennas@mailman.qth.net>,
towertalk <towertalk@contesting.com>
Subject: [TowerTalk] hairpin matches
From: r miles <greenacres113@charter.net>
Date: Thu, 8 Aug 2013 12:41:58 -0400 (EDT)
I recently acquired a 5 el HyGain 10m monobander on a 24' boom. The yagi
uses a hairpin match. The plan is to convert it to 6m. Either a WVO
special on 19' of boom or use the full 24'. Since it's already in place we
are considering using the hairpin. Obvoiusly shorter as the freq is nearly
double 10m. My friend W4HLR will be actually doing the construction. We
would like to hear your experiences with HyGain hairpin matches on
monobanders. Or any monobander. Is there an advantage using a hairpin
rather than gamma or other methods. DX-Eng sells hairpins & say they are
better than gamma, etc. We're hoping to end up with a heavy duty yagi as
the boom & element sizes of this yagi are bigger & heavier than most 6m
yagis. It will be for next seasons 6m Es. If there is one. Hi! Really was
poor this Summer in NW Tn.
Tnx K9IL
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