Hi all,
1/4 wavelenght with 75 OHm coax is a 2:1 impedance transformer.
Dan's article is about the effects of the unused bands. All those pigtails from
the quad to the remote switch are affecting overall performance, even if those
bands are not in use.
According to Dan's article, and if I am not wrong, best approach might be to
use 1/2 wavelength from feed to remote switch, plus 2:1 balun at feed points,
plus a RF choke at the remote switch's output.
73, Maximo - EA1DDO
________________________________
De: TowerTalk <towertalk-bounces@contesting.com> en nombre de Kevin Stover,
AC0H <kstover@ac0h.net>
Enviado: martes, 21 de noviembre de 2017 23:20
Para: towertalk@contesting.com
Asunto: Re: [TowerTalk] Feeding a quad
Cubex Quads recommends 1/4 wavelength 75 Ohm matching sections for each
band. Might need 3/4 for the 10m driven depending how far from the relay
box. So does this NCJ article. ncjweb.com/features/janfeb08feat.pdf
On 11/20/2017 6:40 AM, Martin Sole wrote:
> Dan,
>
> Many thanks. That pretty much says what I wanted to know (and a whole
> lot more!)
>
> It seems to me that a just reach length, or rather some arbitrary length
> close to that is going to be the best compromise.
>
> Martin, HS0ZED
>
>
> On 20/11/2017 14:02, Dan Maguire wrote:
>> Martin, HS0ZED, wrote:
>>
>>>>> The pentaband quad in the ARRL antenna book has had a couple of
>>>>> recommendations as a good design based on my web reading and it
>>>>> makes an interesting point with regard to the feeding method.
>> There is a very detailed study of the feed system for the ARRL
>> pentaband quad in the 5th section of this page:
>>
>> http://ac6la.com/aeautoseg.html
AutoEZ: AutoSeg - Convergence - Currents - Switched
Sources<http://ac6la.com/aeautoseg.html>
ac6la.com
AutoSeg Explained. Perhaps the best way to explain the AutoEZ AutoSeg function
is to show how it differs from the EZNEC Auto Seg function. The EZNEC function
offers ...
>>
>> Dan, AC6LA
>> http://ac6la.com
AC6LA Software<http://ac6la.com/>
ac6la.com
Software to automate and animate antenna modeling and propagation predictions.
>> _______________________________________________
>>
>>
>>
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--
R. Kevin Stover AC0H
FISTS #11993
SKCC #215
NAQCC #3441
ARRL
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