Hi,
Any quad or Yagi is designed with a target on mind. You can't get everything,
so you need to focus on one of the three main parameters; forward gain, rear
gain (F/B), and bandwidth.
You can only maximize two of them. Or you can leave all three balanced, no one
parameter reaching his top limit.
Most commercial designs are "balanced", for average users.
But if anyone wants to maximize his design, he is able to get much better
figures, just from two parameters.
A good example is in the high bands, where bandwidth is not an issue, due
narrow band use (VHF). Then, you can design to get highest figures on front
gain and rear lobes, in a narrow bandwidth. Over only two parameters.
On HF bands things are a bit different.
Newer quad designs for HF include what was called "OWA" style.
Using a specific design technique you can get a balanced response with higher
gain and F/B than traditional designs.
There are some designs (including 6m OWA) and documentation at;
http://www.ea1ddo.es/cubicas.html
And hundred of quad pictures at; http://www.ea1ddo.es/galeria/index.php
73, Maximo
________________________________
De: TowerTalk <towertalk-bounces@contesting.com> en nombre de Roger D Johnson
<n1rj@roadrunner.com>
Enviado: jueves, 1 de septiembre de 2016 13:09
Para: towertalk@contesting.com
Asunto: Re: [TowerTalk] 6 mtr quad
The big question is, over what frequency range and angles does this F?B ratio
hold up?
73, Roger
On 9/1/2016 8:09 AM, Rudy Bakalov via TowerTalk wrote:
> It is worth taking a look at the Swiss quad described in the Rothammel
> Antenna Book, which as far as I can tell was never for sale in English. The
> Swiss quad takes the idea of the HB9CV yagi and applies it to a quad to
> achieve over 30 db F/B with a lambda/8 boom. I have personally used a few of
> the HB9CV yagis and was amazed by their F/B.
>
> The German version of the Rothammel book is available for free online.
>
> Rudy N2WQ
>
>
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