[Boatanchors] antenna question
rayfrijr at msn.com
Thu Jan 16 15:57:02 EST 2014
a folded dipole will need a 4:1 balun for feeding with coax ... or just straight coax feed?
Date: Thu, 16 Jan 2014 12:43:25 -0800
From: gzook at yahoo.com
Subject: Re: [Boatanchors] antenna question
To: jack at n7oo.com; rayfrijr at msn.com; boatanchors at puck.nether.net
The entire driven element.
My 2-meter yagi started out as a Cush-Craft and the gamma match got into very poor condition. I replaced the driven element with a folded dipole with the 2:1 rod diameter ratio. My 222 MHz yagi
still has the original gamma match. Basically, the type of match used on the driven element really doesn't matter.
I obtained my 6-meter beam, along with other things, and there was no indication of the manufacturer. It resembled the Cush-Craft but there were a few things different. The driven element was in very poor condition and the gamma match was in even worse condition. Glen, K9STH
On Thursday, January 16, 2014 12:43 PM, Jack Taylor <jack at n7oo.com> wrote:
Glen, which horizontal element are you referring to, the gamma rod or the DE?Jack - n7oo-----Original Message----- From: RAY FRIESSSent: Thursday, January 16, 2014 11:15 AMTo: Glen Zook ; BoatAnchorsSubject: Re: [Boatanchors] antenna questionActually, I
misspoke... My two meter antenna is the Cushcraft just like yours. Two 11 element phased. I have themvertically mounted and phased for FM. It's the driven elements on them that are gamma matched and kind of incrummy shape. I thought instead of rebuilding the gamma matches, I'd just build a different kind of driven elementthat 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 -0800From: gzook at yahoo.comSubject: Re: antenna questionTo: rayfrijr at msn.com;
boatanchors at puck.nether.netGenerally, 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, K9STHWebsite: http://k9sth.com 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_______________________________________________Boatanchors mailing listBoatanchors at puck.nether.nethttps://puck.nether.net/mailman/listinfo/boatanchors-----No virus found in this message.Checked by AVG - www.avg.comVersion: 2012.0.2247 / Virus Database: 3681/6508 - Release Date: 01/16/14
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