TopBand: ATUs on 160m

[Donald B. Hall]

Steve,

The minimalist philosophy applies not only to 160 meter antennas but to
all the radio items.

Keep it the simplist possible.  SWR doesn't need to always be 1:1.

Don't give the RF many places to go except to the antenna since that
is the only place it does any good!!

73

Don K5AQ

----------
> From: Steve Ireland <sire@omen.com.au>
> To: topband@contesting.com
> Subject: TopBand: ATUs on 160m
> Date: Monday, November 24, 1997 4:32 AM
> 
> Just some 'food for thought' for those out there using 160m dipoles fed
with
> open wire so they can use the antennas on the other low bands.
> 
> Until recently, I used a similar arrangement until I finally got up a
good
> seperate antennas for 80m.  At this point, I junked the open wire (about
60'
> in total), commercial T-match ATU (plus balun) and put RG58 coaxial cable
> and a choke balun on instead.  The difference was quite startling - about
1
> 'S' point improvement in my 160m signal.
> 
> The open wire was home made, using beverage (drinks) tubing and,
latterly,
> commercially made spreaders.  As open wire goes, it was great stuff and
> noticeably better in performance than good quality 300 ohm ribbon. 
> 
> I used a variety of ATUs on the dipole/open wire, including a balanced
> parallel tuned ATU (link coupled) and commercial T-match minus the balun
and
> the performances were all about the same.  I also tuned the T-match in
the
> recommended fashion to use as little of the inductor as possible.
> 
> It was only when I junked ATUs and open wire all together that things
> improved - the old hands who say avoid inductors in 160m ATUs/antennas
are
> right. One of the VK6 160m gang here thought I had bought some kind of
super
> linear when I changed to the dipole with co-ax feed!!
> 
> For those who like to use their 160m dipoles on 80/40m, it perhaps might
be
> interesting to see how parallel dipoles for 160/80/40m with a choke balun
> and co-ax feed go at your QTH, rather than using open wire feed.  On the
> other hand, maybe you have a very low loss ATU...or do you?
> 
> 73,
> 
> Steve, VK6VZ
> 
> 
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