[TowerTalk] 10 throu 20 beam traps or no traps

[Bryan Swadener via TowerTalk]

I like my Force12 C-4XL (40/20/15/19m yagi). There are 2 elements
on each band.  10m uses two driven elements, IME to have low
VSWR across the band.

It is an interlaced design, using mutually-coupled driven elements
on 20/15/10m.  Elements for those bands are full length.  40m is
linear-loaded with elements about 39 feet long.  Tuning is simple.
There are no adjustments on 20/15/10m.  40m has three
adjustments -- the two linear loading lines, and an inductor or
"helical hairpin" across the feedpoint. Bandwidth is about 100 KHz.

It is supposed to also work on 17 & 12m with an ATU.  My
TS850SAT likes it well enough w/o the tuner active on 17m.
The ATU easily "dials it in" on 12m.

A few years ago, I decided it was high time to get serious
with a good-size tower and yagi.  The yagi(s) HAD to cover
40m. I found the F12 for sale on QTH and QRZ classifieds
for half the cost of the new Delta 4 XL.  After reading Ward &
Steve's fine yagi comparison book, I pulled the trigger. The
seller said it needed some repair, and he included the repair
parts.  It came to me in two round cardboard tubes.  All I
needed to buy was a few hundred pop rivets.

I'm as happy as a pig in slop!

vy 73,
Bryan WA7PRC


>________________________________
> 
>Date: Mon, 23 Jun 2014 11:33:32 -0500
>From: "john at kk9a.com" <john at kk9a.com>
>Subject: Re: [TowerTalk] 10 throu 20 beam traps or no traps
>
>There are compromises on all antennas, especially with multiband beams.
>Interlaced elements have no trap losses and are designed for optimum
>element spacing with minimal interaction from the non resonant elements.
>If these are your choices, I would definitely pick the OptiBeam.  In my
>opinion, OptiBeam's quality and customer service are second to none.
>
>John KK9A
>