[Boatanchors] antenna question
rayfrijr at msn.com
Thu Jan 16 13:15:46 EST 2014
Actually, I misspoke... My two meter antenna is the Cushcraft just like yours. Two 11 element phased. I have them
vertically mounted and phased for FM. It's the driven elements on them that are gamma matched and kind of in
crummy shape. I thought instead of rebuilding the gamma matches, I'd just build a different kind of driven element
that can be attached to the boom, or a type that I can insulate from the boom with a small plastic block mounted to the boom itself.
Date: Thu, 16 Jan 2014 10:03:54 -0800
From: gzook at yahoo.com
Subject: Re: antenna question
To: rayfrijr at msn.com; boatanchors at puck.nether.net
Generally, the type of match on the driven element doesn't matter.
On both my 6-meter yagi and 2-meter yagi, I have changed the driven element to a folded dipole. This was done because I was having problems with the gamma match on both antennas.
If you make one of the horizontal sections half the diameter of the other, the impedance will be close to 200-ohms instead of the 300-ohms when both sections are the same diameter. Then, matching to 50-ohm coaxial cable only requires a simple coaxial cable balun.
My 6-meter yagi and my 2-meter yagi can be seen in the second photo at:
http://k9sth.com/uploads/Antennas_At_K9STH.pdf Glen, K9STH
On Thursday, January 16, 2014 11:03 AM, RAY FRIESS <rayfrijr at msn.com> wrote:
First of all ... let me take a moment to express sadness at the loss of Glen's fellow author, Glen W6ISQ. While he was not a "technical" author like Glen, it was always a real joy to read his stuff, just like it was to read Glen's stuff in the magazines.Now .. I have an antenna technical question.I have a HyGain 11 element two meter beam that uses gamma matching. The question I have is, does the type of drivenelement matter on a given beam as long as the driven element is adjusted for the best match at a given frequency?In other words, I am refurbishing the beam and have given some thought to redoing the driven element and usinga dipole, folded dipole or hairpin, or a Y match driven element.Ray WA7ITZ
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