Only reason a matching device is usually required is when the antenna is
multi-band as it was originally. But if you're going to make a single
band 20 meter quad, Mike and Tom's advice below should work just fine.
Noel
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Tom Sessions
Sent: Monday, March 22, 2004 10:31 AM
To: towertalk@contesting.com
Subject: RE: [TowerTalk] quad design
Mike is so right. Whether you use formulas by hand or modeling
(essentially the same thing except the computer does the math), you are
probably going to have to make adjustments to get the SWR "resonance"
and/or FB you want. On the other hand, you might get lucky and get it
what you want the first time.
73,
tom K4RV
> [Original Message]
> From: Michael J. Castellano <km1r@cshore.com>
> To: <towertalk@contesting.com>
> Date: 3/22/2004 15:03:23
> Subject: [TowerTalk] quad design
>
> you dont really have to go through the modeling route.
>
> simply make the driven element 1 wavelength at the intended frequency,
and the reflector 5% longer.
>
> You can feed it directly with 50 ohm line or if you are a purist, use
> a
balun of some sort.
>
> Gain will be good, F/B acceptable, and it is simple, quick and cheap.
>
> The ARRL boom length of 13 feet is good, but your existing 12 foot
> boom
will be fine, and might not be
> worth the mechanical trouble of lengthening. (Dont think you will
> really
notice a difference in actual use)
>
> 'I'll probably get flamed for this, but in my opinion, we are
"reinventing the wheel" by modeling everything.
>
> The textbook approach works fine, although some final adjusting might
> be
in order.
>
> Been building quads the old fashioned way for decades... 1 wavelength,
reflector 5% longer... it works!!!!!
>
> Good luck with it, hope to hear you on Field Day...!!!
>
> 73, Mike KM1R
> _______________________________________________
>
> See: http://www.mscomputer.com for "Self Supporting Towers",
> "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
any questions and ask for Sherman, W2FLA.
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless
Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with
any questions and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
_______________________________________________
TowerTalk mailing list
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