[Boatanchors] antenna question

Jack Taylor jack at n7oo.com
Thu Jan 16 13:43:30 EST 2014


Glen, which horizontal element are you referring to, the gamma rod or the 
DE?

Jack - n7oo

-----Original Message----- 
From: RAY FRIESS
Sent: Thursday, January 16, 2014 11:15 AM
To: Glen Zook ; BoatAnchors
Subject: Re: [Boatanchors] antenna question

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

Website:  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


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