[TowerTalk] Interaction Issues

Jeffrey Cantor k1zn at att.net
Sat Apr 8 22:07:34 EDT 2017

 I recently had some tower work done.  Ihave a Rohn 25 tower up 60 FT.  I have a C-3 and a 6-element Cushcraft 6Mon it.  Both antennas were doing fine – SWR essentially flat on the C-3and around 1.5:1 on the 6M.  They were both mounted on a 9 FT mast,separated by about 6 FT. The job was to replace the 9 FT mast witha 15 FT lighter mast and to install a new 12/17M WARC Cushcraft antenna.   The new setup had the 12/17M antenna atthe top of the mast; the 6M in the middle, phased at 90 degrees to the otherbeams - – separated by roughly 6 FT between it and the lower C-3 and the WARC. After the install, I am noticing a 2.0:1. 2.4:1 SWR on the C-3 on 20M only; 15M & 10M are OK.  On the 6M –3.0+ SWR. Do I have an interaction problem betweenthe 6M and C-3? Should the 6M be at the top of themast?  Offset to the others, or not? Jeff/ K1ZN

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