[TowerTalk] Yagi designs?

[jeremy-ca]

He also admitted that his 6el design was not optimum.

The closed spaced R and D1 was a radical departure for the norm at the time. 
It was several years before the concept was translated to VHF/UHF with great 
success.

I spent lots of time with YO trying to improve on the 4PV and got nowhere of 
any importance. That design is optimum for that boomlength for what it 
offers. Adding another director improved VSWR BW but it wasnt important to 
my needs. It loads fine anywhere and the gain is almost flat.

There is a whole lot more than simply looking at the element mounting 
methods. For a grounded element the mounting plate also has to be 
calculated. And then there is the element taper, mine went from 1 1/4" down 
to 1/2". Its all covered in Jims supplements which did not get general 
distribution. The antenna was a plug and play straight from his 
calculations.

Carl
KM1H



----- Original Message ----- 
From: <john at kk9a.com>
To: <TOWERTALK at contesting.com>
Cc: "jeremy-ca" <km1h at jeremy.mv.com>
Sent: Thursday, July 19, 2007 9:38 PM
Subject: Re: [TowerTalk] Yagi designs?


>I have read W2PV's yagi antenna design book many times and there is
> certainly a lot of useful information in it.  However, I believe that  his
> yagi designs are not optimum.  He used equal spacing between the elements
> and newer designs use closer spacing for the reflector and first director 
> to
> improve bandwidth.  Since the boom is 90 degrees from the antenna, I don't
> see how it effects the pattern.  Also unless you are using insulated
> elements, you need to add the elements to the boom to determine it's
> resonate frequency.
>
> John KK9A
>
> To: towertalk at contesting.com>
> Subject: Re: [TowerTalk] Yagi designs?
> From: "jeremy-ca"
> Date: Thu, 19 Jul 2007 17:25:49 -0400
> List-post: <mailto:towertalk at contesting.com>
>
> Nothing beats the W2PV designs for gain or F/B especially over just the CW
> band. With 4 elements on 40/27/20 foot booms for 20/15/10M the wind load 
> is
> less than designs with more elements. The booms are non resonant on any of
> those bands so stacking interference is minimized allowing closer spacing.
>
> Ive used them singly or in stacks since 1983.
>
> Carl
> KM1H
>
>