[TowerTalk] Elevated Vertical with No Radials on Metal Roof
n4zr at contesting.com
Thu Aug 17 17:14:20 EDT 2006
I had a Butternut HF9V on the 25x45 foot metal roof of my garage about 12-15 feet off the ground. In order to finesse the bonding issue, I used a pair of 125-foot radials that were laid out serpentine fashion to couple to each of the sheets of roofing, rather than relying on the inter-sheet connection. I didn't have an earth ground connection, but I agree I probably should have. I don't know whether the idea of capacitive coupling this way has any technical merit, but the antenna worked quite well, and even though it was only about 40 feet from the house/shack, no RFI was evident when using it in an SO2R setup as the second radio antenna.
73, Pete N4ZR
At 03:56 PM 8/17/2006, Jim Brown wrote:
>On Thu, 17 Aug 2006 10:04:43 -0500, ve4xt at mts.net wrote:
>>You do need to connect the roof to the radial attachment point of the
>>Some things to watch for, however: RFI is one. Have an intermittent or
>>slightly corroded connection at a seam and you're in for RFI.
>I agree with all of Kelly's comments, and would emphasize his advice for
>good bonding together of the various elements of the roof, both to make it
>more stable (and a more effective ground plane), and to prevent RFI. And
>also the need for an earth connection for lightning protection.
>Jim Brown K9YC
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