[TowerTalk] optimum vertical length

[jimlux]

Michael Ryan wrote:
> Where did that 12 - 15 ft above a structure come from?  - m

I'm not sure, but you see restrictions of "12 feet above the highest 
point of the structure" for all sorts of things, so I suspect the FCC 
just adopted it for the old CB antenna rules. I just looked up the newer 
rules and it's 20 ft.

The OTARD rules also have the 12 foot limit

Probably comes from some standard structural size for pipe or something.


> 
> -----Original Message-----
> From: towertalk-bounces at contesting.com
> [mailto:towertalk-bounces at contesting.com] On Behalf Of jimlux
> Sent: Tuesday, June 02, 2009 9:44 AM
> To: Dan Zimmerman N3OX
> Cc: towertalk at contesting.com
> Subject: Re: [TowerTalk] optimum vertical length
> 
> Dan Zimmerman N3OX wrote:
>>> If one uses the old CB antenna rules of 12-15 ft max height above
>>> structure as a constraint, are you better off with some sort of short
>>> vertical dipole, up 30 ft on the roof, or with a 45 ft vertical, on the
>>> ground?
>