I would stack the 40m antennas horizontally with 5/8 wave length spacing
between the two towers (26m).
One wave length spacing gives you 1dB more of gain but also side lobes and
worse f/b.
73
Peter, DJ7WW
-----Original Message-----
From: CQ-Contest [mailto:cq-contest-bounces@contesting.com] On Behalf Of
Ranko Boca
Sent: Freitag, 20. April 2018 16:10
To: donovanf@starpower.net
Cc: cq-contest
Subject: Re: [CQ-Contest] 4O3A Station rebuild
Hi Frank,
nice to hear from you.
I will have 3 rotary towers. On 40M I will have 2/2, plus four tribanders.
Towers are in triangle, and will be able to turn two of them toward USA or
JA. Want to have optimized 4x 2L40 in H frame configuration.
Exactly what you are saying, I have to look for 20M antennas, to fit this
optimized 40M distance of towers. Based on its boom length, I will look for
adequate tribanders, or will decide to make it by my own.
I hope it is more clear now?
73
Ranko
On Fri, Apr 20, 2018 at 4:00 PM, <donovanf@starpower.net> wrote:
> Hi Ranko,
>
> You didn't mention WHAT You want optimize...
> Maybe you want to optimize gain in a 4 Yagi stack?
>
> It's not possible to optimize gain on both 40 and 20 meters.
> My recommendation is to optimize gain on 40 meters and
> Use long boom tribanders to optimize gain on 20 meter
> And not try to use two towers for horizontal stacks.
>
> EZNEC can easily determine optimum spacing
>
> Good luck with your rebuild!
>
> 73
> Frank
> W3LPL
>
>
>
>
> ----- Original Message -----
> From: Ranko Boca <4o3a@t-com.me>
> Cc: Contest Reflector <cq-contest@contesting.com>
> Sent: Fri, 20 Apr 2018 04:04:04 -0400 (EDT)
> Subject: [CQ-Contest] 4O3A Station rebuild
>
> When making something big, such as a life time contest project, it is
> better to share and listen for advice. Here we have an experienced group
of
> contesters and maybe someone has something to say that I am not
considering
> at the moment?
>
> I am intending to rebuild the 4O3A station. One of the tasks is to put two
> towers in stack toward USA.
> On each tower I will have a stack of 2L40, together with a tribander
stack.
> The idea is to optimize horizontal distance of towers on 40M and 20M.
Other
> bands can't be optimized, and are not that important.
>
> I am still looking for tribanders designs, either to buy them or to build
> them.
>
> Any advice is welcome.
>
> 73
> Ranko
> _______________________________________________
> CQ-Contest mailing list
> CQ-Contest@contesting.com
> http://lists.contesting.com/mailman/listinfo/cq-contest
>
>
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