The unchangeable rule is nothing on the roof other than self-supporting
vertical antennas mounted to the penthouse wall. Sometimes you just have to
work with what you've got...
If the big one ever hit, we would have far more flexibility to put up a wire
antenna in the aftermath (when it would have the most need anyway).
It took us nearly a decade to get the School Board to allow VHF/UHF antennas
to be installed at the shelters- a critical need. This is not a critical
enough need to burn up good will over.
Doug
> -----Original Message-----
> From: towertalk-bounces@contesting.com [mailto:towertalk-
> bounces@contesting.com] On Behalf Of Jim Brown
> Sent: Thursday, July 30, 2009 12:46 PM
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] Building Top Vertical
>
> On Thu, 30 Jul 2009 11:29:13 -0400, Doug Rehman wrote:
>
> >3) No radials on the vertical (unless they're only about 18")
>
> >4) It will be mounted to the wall of the elevator penthouse
>
> >5) It can be tied into the perimeter lightning ground
>
> Your 100 mph requirement without guying really limits the
> possibilities. I would ask WNY no guying? If the objection is to
> conductive guys that could cause problems, I would suggest a non-
> conductive guy material like Phillystran, which is quite strong
> and has very low visibility (it's black). Also, don't be afraid to
> play the "homeland security" card.
>
> For antenna hardware, I would look at DX Engineering -- their
> hardware seems to be more robust than most, and their engineering
> tends to be good. I would also try to limit the frequency coverage
> to what you actually need. Anything you do to the antenna itself
> to make it cover multiple bands is going make it less robust.
>
> I'm assuming that the feedline will be relatively short (less than
> 100 ft). If so, I'd run RG8 to it and put up the tallest, most
> robust aluminum that you can and tune it from the shack. Just make
> sure that it's not close to a half wave on any band where it has
> to work.
>
> One positive thing though -- a low impedance bond of the coax
> shield to the building steel and the lightning protection system
> will serve quite well in place of radials.
>
> 73,
>
> Jim K9YC
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