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[Towertalk] HF antennas

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Subject: [Towertalk] HF antennas
From: (Frank W8HO)
Date: Fri, 19 Jul 2002 16:18:31 -0400
I would highly recommend consideration of the Optibeam OB 11-3 rather than 
those you have listed below.  You can add good coverage of 17m and 12m with 
the addition of the OB 4-2 stacked above the OB 11-3.

The one arrangement that most concerns me from a safety standpoint is the 
Hygain stack.  Putting your 205 ca that far above the top plate of your 
tower will induce severe stresses on your tower....stress that is far 
beyond what it is designed to handle.

The same Hygain stack lowered to put your 205ca one foot or so above your 
top plate might well be safe but I would reevaluate all of your plans to 
make sure you are not exceeding the capabilities of your tower.  I am not 
sure that the top section of the HDX 555 will hold a rotator capable of 
handling a couple of your proposed stacks.

Whatever you decide....Good luck, and be safe.

Hope to talk with you on the air real soon.....

73 de Frank W8HO

At 02:56 PM 7/19/2002 -0400, you wrote:
>As I patiently wait for my new HDX-555 tower to arrive, my thoughts have
>drifted away from what size conduit to use or how to pour concrete, to what
>HF antennas I'll be erecting.  My operating habits consist of working toward
>my DXCC Honor Roll (313 confirmed) and 5BDXCC, with a smattering of SSTV,
>RTTY and ragchewing.
>I operate 70% of the time on 20mtrs with the remaining 30% divided between
>10, 15, 40 and 75.  I'm replacing a 5 element tribander.
>Here's what I'm considering at this point for the new 55' tower with a 20'
>Hygain 5 el 20mtr monoband Hygain 205CA at 60'  6.5dBd
>Hygain 10/15mtr duobander Hygain DB1015 at 72'  5.2dBd
>Force12 C-31XR at 60' for 10/15/20mtrs  6.0dBd on 20mtrs
>                                         6.3dBd on 15mtrs
>                                         7.4dBd on 10mtrs
>Hygain TH-11DX at 60' 10/12/15/17/20  6.4dBd on 20mtrs
>                                       6.2dBd on 17mtrs
>                                       5.9dBd on 15mtrs
>                                       5.3dBd on 12mtrs
>                                       7.0dBd on 10mtrs
>I've had a HyGain TH-6DXX, 205CA and DB1015 in the past and never had any
>problems.  I've also heard good things about the Force12's but I've also
>heard the rivets sometimes work loose.  For multiband coverage, it sure
>appears that the TH-11DX would be ideal but I'm open for suggestions.
>David, K4ZZR
>P.S.  As per all of the suggestions, I added a 2 1/2" underground conduit
>next to the 1 1/2" conduit so I should have plenty of room for cables now.
>I'm also working up a webpage with photos of preparing the tower base (me
>digging with a mini-backhoe!, rebar and concrete pouring....

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