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Re: [TowerTalk] OWA Yagis was 40m 4el KLM - replacing linear loading wit

To: towertalk <towertalk@contesting.com>
Subject: Re: [TowerTalk] OWA Yagis was 40m 4el KLM - replacing linear loading with coils
From: Steve Maki <lists@oakcom.org>
Date: Thu, 30 Apr 2020 20:24:24 -0400
List-post: <mailto:towertalk@contesting.com>
The boom length has more to do with gain than element count.

I'm guessing if you had OWA's you would be sold on them.

Especially if:

1) Your amp(s) are not solid state broadband types.
2) You have stacked monobanders.

The flat SWR curves give you easy to achieve no-amp-retune wide frequency moves and stack combos. You go - yep, this is the way it was meant to be.

-Steve K8LX

On 04/30/20 19:15 PM, sawyered@earthlink.net wrote:

In my view, the discussion on OWA yagis is about the element count and the
boom length.  People will describe that they have a 5 el or 6 el yagi.
However, an OWA yagi has 2 elements that are really closely coupled driven
elements and not contributing to gain.  Vs a conventional yagi where all
elements except the single driven element contribute to gain.  So a 6el OWA
yago does not have the same gain as a 6el conventional yagi on the same
boom.  Sure you can add boom length to the OWA but you can also add boom
length to the conventional yagi and the OWA will always lose in gain.

I am not bashing OWAs.  They are an excellent compromise of wide band low
SWR vs gain but it is a compromise.

The other side of the coin is the radio's capability to deal with a higher
SWR and the losses created in the coax due to the SWR being higher in
portions of the band.

I have all conventional yagis.  The 2:1 bandwidth of the my yagis are 28000
- 28750.  2100 - 21375.  14000 - 14300.  7000 - 7185.  The amp is at full
power up to 3L1 SWR.  And I have most of my runs using LDF5-50.  So in my
opinion, for a given boom length, the trade of the OWA isn't worth the gain
loss outside the 2:1 edges of the band.  Especially because I am almost
never running in those sections of the band - where gain is most important.

Like everything, there is no free lunch in engineering trade-offs.
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