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[Towertalk] Shunt Fed Tower 160/80

To: <>
Subject: [Towertalk] Shunt Fed Tower 160/80
From: (WL7M)
Date: Wed, 04 Sep 2002 17:30:36 -0800
Hi Gene,

Sounds like you have all the goodies to make it work.  I could have 
switched the line at the tower also, but I only had one variable 
my great delight, it worked!  Then again, that DOES mean a trip to the 
tower in the winter through 6 or 8 feet of snow to change bands....your 
setup sounds like the better deal!  Hope to hear you on 160 this 
winter!  I'd be happy to make your day!  73, Joe

At 04:56 PM 04-09-2002, you wrote:
>      Congrats on your success!  I wasn't able to get my 64-foot Trylon to
>load on both 80 and 160 with one set of shunt wires, so I strung up two
>separate sets.  But based on your experience, I might just try it again.  My
>thinking is I'd either switch one feedline between two caps at the base,
>switch between two lines and caps (I have a remote switch at the tower), or
>even use a motor-tuned variable cap.
>      BTW - I need only KL7 for WAS on Topband so maybe we could try for a
>sked sometime this winter?  Would be interesting to test our respective
>antennas (I also have an inverted L for 160.)
>GL es 73 de
>Gene Smar  AD3F
>-----Original Message-----
>From: WL7M <>
>To: <>
To: <>
>Date: Wednesday, September 04, 2002 7:06 PM
>Subject: [Towertalk] Shunt Fed Tower 160/80
> >My thanks to those on the reflector whose ideas I've glommed onto over the
> >years.  I finally decided to try a shunt fed tower for 80 and 160
> >meters.  Having a humongous variable capacitor with huge spacing, I gave it
> >a try.  I have no idea what the range is on the variable cap, but it
> >works!  I almost forgot the essential "hook the coax braid to the bottom of
> >the tower" step, but a recent TTer confessed to having made that mistake,
> >and, I did too.  When I did that, the SWR fell right into range.  So, my
> >thanks to that humble but wiser soul who passed on that bit of information.
> >
> >My tower is 40 feet of Rohn 25G, with a Mosley Pro57B about 8 feet above
> >it, and a Cushcraft 5 element 6 meter yagi about 8 feet atop
> >that.  Apparently there is sufficient capacity hat effect to make it work
> >nicely.  I attached an aluminum rod to the bottom of my Hazer that extends
> >out about 30 inches.  From that, I attached a wire to run down to the
> >ground.  Hooking up the cap and properly connecting the coax, I set the
> >Autek Antenna analyzer to 3.535 MHz and adjusted the is barely
> >meshed, and the SWR was 1.3 : 1.  Returning to the shack, I fired up the
> >Icom 756Pro and it agreed.  My Alpha 87a was next - but I took the
> >precaution of running it through the Palstar AT4K tuner to make sure I had
> >a good match.  Worked great!
> >
> >For 160 meters, the variable cap is about 1/3 meshed, and the SWR is also
> >about 1.3 : 1.  That means I have to wade through 6 feet of snow in the
> >winter to switch bands, but I'm sure it will be worth it!  As mentioned on
> >this reflector before, if you bring the bottom of the wire toward the tower
> >base, or away from it, it will affect the SWR as well.  I moved mine to
> >about 2 feet from the tower base and the SWR dropped to 1.2 : 1.  I have a
> >few radials attached at the tower bottom, and I'm sure I can use even
> >more.  That's another project to finish before the winter sets in (which
> >will be about a month from now!)
> >
> >Thanks again to the TTers for all their collective ideas!  Hope to work you
> >on 80 and 160 this winter!
> >
> >73,
> >Joe
> >WL7M
> >Fritz Creek, Alaska
> >
> >
> >_______________________________________________
> >Self Supporting Towers, Wireless Weather Stations, see web site:
> >Call 888-333-9041 to place your order, mention you saw this ad and take an
>additional 5 percent off
> >any weather station price.
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