[TowerTalk] Interaction Issues

[n8de at thepoint.net]

Totally agree with John, as the BOOM of the 6m yagi is the culprit!

73
Don
N8DE


Quoting john at kk9a.com:

> I did not suggest changing the coax length, the original post said   
> that he changed the phasing by 90 degrees.  I later read he meant   
> that he rotated the 6m beam 90 degrees.  I am not sure why he   
> rotated the antenna now after it was previously in line with the C3.  
>   In my experience from modeling my antennas this often makes   
> interaction worse.
>
>
>
> John KK9A
>
>
>
>
>
> From: Chuck Dietz [mailto:w5prchuck at gmail.com]
> Sent: Sunday, April 09, 2017 1:22 PM
> To: john at kk9a.com
> Cc: towertalk at contesting.com
> Subject: Re: [TowerTalk] Interaction Issues
>
>
>
> No reason to change the coax length, check the coax itself by   
> disconnecting and putting an analyzer at the remote switch on the   
> tower, if there is one.
>
>
>
> Chuck W5PR
>
>
>
> On Sun, Apr 9, 2017 at 11:29 AM, <john at kk9a.com> wrote:
>
> Phasing will have no effect but I am not sure why you would change the coax
> length. If the 6m beam is 90 degrees to the C3 and the 6m boom length is
> around 1/2 wl on 20m or less than that but electrically 1/2 wl due to
> grounded elements there will be serious interaction.
>
> John KK9A
>
> To:     "towertalk at Contesting.com" <towertalk at Contesting.com>
> Subject:        [TowerTalk] Interaction Issues
> From:   Jeffrey Cantor <k1zn at att.net>
> Reply-to:       Jeffrey Cantor <k1zn at att.net>
>
> 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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