Fwd: Re: [TowerTalk] 2 vs 3 ele 40m yagi - opinions?

[Bob Otto]

Hello Dan,

Hmmmmmmmmmmm    Is  the  TX2  suitable for turning a C31XR *and* a 40M
Beam??

73 from.......

Bob Otto
N8NGA@one.net
Cincinnati, Ohio

Time Written:
7:11:47 AM
Attachments:
<none>

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DXCC 10M         ** DX is !! **        WAS 10M
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Tuesday, February 06, 2001, 1:53:42 AM, you wrote:

DL> I am building a new station at my vacation place in Northern CA.  I will run
DL> a C-31XR for 10-20 meters, and want to stack a 40 meter yagi with the C-31.
DL> The rotor will be a Tail Twister.  The station will be used primarily for
DL> domestic contesting - Sweepstakes, NAQP, CQP, etc.  I have steeply sloping
DL> foreground to the US.

DL> I have the remains of an old Telrex 3-29 40 meter yagi.  The boom is pretty
DL> beefy, and 29 feet long.  I plan to design and build a 40 meter yagi from
DL> the parts, either a 2 element 50 ohm direct dipole feed yagi on about 22' of
DL> the boom, or a 3 element beta match fed 3 element yagi on all 29'. I have
DL> two questions:

DL> 1) The 2 element yagi will be lighter, put less torque on the rotor, have
DL> less effective wind area, etc.  It will also have .5 - 1 db less gain than
DL> the 3 element, and a fair bit less front-to-back ratio.  Any thoughts on
DL> which way to go?  Am I just asking for huge mechanical issues if I put up
DL> the 3 ele., especially with the rotor?

DL> 2) I have to choose whether to use full size 40 meter elements, or to load
DL> them somehow (probably capacity hats at the ends of the elements.  4 2'
DL> spokes shortens the elements to about 56' - 8' of hat spokes saves 5.5' of
DL> tip length (per side).  Maybe F12 style linear loading line the new N
DL> elements.).  It seems clear that electrically, the full size elements are
DL> better.  Mechanically, it isn't clear to me which way to go.  Any thoughts
DL> on why the shortened elements might be better?  Less torque on the
DL> mast/rotor?

DL> Thanks much!

DL>             ***dan, K6IF

DL> P.S.  My web site, including the 10 meter contest story, will be back on the
DL> air soon at http://www.k6if.com .  My ISP went out of business rather
DL> suddenly, crashing my old site.


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