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Author Topic: Gap Titan DX On a Metal Roof?  (Read 1463 times)
WF7BSR
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Posts: 35




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« on: November 11, 2012, 08:55:39 PM »

I have a 35' x 15' flat aluminum roof (wood-framed) over the end of my drive way, at approx. 18 feet high (was designed to shade motor-home, think "over-sized carport")...concrete pad below and supported by 10 x 3-inch diameter iron pipes (five on each side).  It was suggested to me that I try mounting my new Titan DX right on top of the metal roof, because the metal roof would work with the antenna rather than against it. But I've read elsewhere that being near metal structures, fences, etc. causes problems with the Titan DX?

The only other place I could mount it would be on the roof of my mobile home (asphalt shingle roof), but it would be within 20-30 feet of the same metal roof...which was why I was advised to try mounting it on the metal roof itself...the thought being that instead of fighting the influence of the nearby metal roof I would be using it to help the antenna.  Am I being given sound advice? 

Also, if mounting the Titan DX on the metal roof is OK, how critical would it be that the antenna is centered on the roof...if it were mounted on one of the long sides would it cause it to be directional?  Since the metal roof is a long rectangle at approx. 2:1 would it not still be directional in the two long directions if centered (hope I worded that correctly)?

Thank you for your time and assistance;
Raymond - WF7BSR
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WX7G
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Posts: 6049




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« Reply #1 on: November 12, 2012, 03:01:01 AM »

I took a look at the Gap Titan DX manual and see no reason why is cannot work when mounted on the metal roof. Mounting at an edge may affect the radiation pattern but not severely. I would mount it where it is easiest to mount, tune it up, and get on the air.
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AC4RD
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« Reply #2 on: November 12, 2012, 03:49:47 AM »

You also might try calling the Gap people and asking--they were very helpful about how to mount the Eagle I bought a dozen years ago. 

I'm not sure about the Titan, but the Eagle was basically a loaded dipole, not a base-fed vertical.  It had the feedpoint in the center, halfway up the antenna's height.  If the Titan is the same, it makes it less fussy about mounting. 

GL with the Titan!
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WF7BSR
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Posts: 35




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« Reply #3 on: November 12, 2012, 06:45:04 AM »

Thank you for the replies and information.

Thank you for your time and assistance;
Raymond - WF7BSR
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WX7G
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Posts: 6049




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« Reply #4 on: November 12, 2012, 07:10:53 AM »

I will model your antenna and motor home port and report my findings.

AC4RD is correct that the Gap Titan is center fed. However, center feed does not change the current distribution in any way. It does move the feedpoint to a higher impedance point and looks good in advertising.
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WF7BSR
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Posts: 35




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« Reply #5 on: November 12, 2012, 07:31:23 AM »

Called the Gap company in Florida, @ 772-571-9922, and spoke to Chris who said that if I mount the Gap Titan DX at four to five feet above the metal roof it (the antenna) will not "see" the metal roof and so will not interact with it.  So some time this week that will be my next project.

Thank you for your time and assistance;
Raymond - WF7BSR
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K7KBN
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Posts: 2802




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« Reply #6 on: November 12, 2012, 09:19:16 AM »

The Titan DX is a pretty heavy antenna, with a bit of wind loading area.  I'd recommend a few non-metallic guys.
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73
Pat K7KBN
CWO4 USNR Ret.
WF7BSR
Member

Posts: 35




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« Reply #7 on: November 12, 2012, 10:58:01 AM »

Good advice re: guying...I go overboard on such things (I'm told) -- I currently have my home-brewed fan-dipole on a 30-foot mast made of 1-inch water pipe and it has six guy ropes: 3 at 20-foot mark and 3 at the top, and it is attached via 18-inch long standoff to the side of my patio (4"x 6" frame) and the base is bolted to a concrete footer with four 18-inch pieces of all-thread.  Water pipe is not a good choice for something like this, but with all the guy ropes it doesn't move much at all in the wind. Will put guy ropes on the Titan DX as well.

Thank you for your time and assistance;
Raymond - WF7BSR
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