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[TowerTalk] TH11 and Shorty 40, Revisited

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Subject: [TowerTalk] TH11 and Shorty 40, Revisited
From: (Dick Flanagan)
Date: Wed, 4 Aug 1999 05:55:03 -0700
>From: "Bob Thacker" <>
>Just got the TH11 up and find out that the VSWR on 17 meters is
>relatively high, about 1.9.  BTW, rechecked all measurement 4 times
>while on the ground, so there is no chance for a wrong element length.
>All traps where disassembled and checked for integrity. The Autek
>analyzer calculates a 1.0 VSWR at 17.760 Mhz though. Approximately 10
>feet above the TH11 is an old Hy-Gain 402BA which is as high as the mast
>will allow. The TT archives say that acceptable spacing is anywhere from
>8 to 14 feet. IMHO, I think the trouble is the 40 interaction causing
>the VSWR to rise.
>Any thoughts and possible cures, short of a new mast?

I have a TH11DX with a 40-2CD Shorty 40 twelve feet above it and a
seven element six meter beam between the two of them.  My 17 meter SWR
is right where it should be.

TH11DX SWR measurements on all bands and photos of the installation can
be found at my web site

I am very pleased with the performance of this combination.  I hope you
are successful in finding the cause of your problem.

73, Dick

Dick Flanagan W6OLD CFII Minden, Nevada DM09db (South of Reno)

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