[TowerTalk] optimum vertical length

Joe Subich, W4TV lists at subich.com
Tue Jun 2 22:03:01 PDT 2009


> Correction... the FCC specifically rejected a particular limit.. They 
> had received comments prior to the rulemaking recommending the BOCA 
> building code which says that permits are not required for structures 
> less than 12ft above highest point.

Actually the very old rules for Citizens Band did have a "20 feet above 
the structure" limit.  If I recall correctly - this comes from 40 years 
ago - the rule applied to the highest point of the antenna which meant 
that the base of a typical 5/8 wave CB vertical had to be at the top 
of the structure.  

Of course, like just about everything else with CB, the rule was 
generally ignored <G>. 

73, 

   ... Joe, W4TV 
 



> -----Original Message-----
> From: towertalk-bounces at contesting.com 
> [mailto:towertalk-bounces at contesting.com] On Behalf Of jimlux
> Sent: Tuesday, June 02, 2009 11:47 PM
> To: Michael Ryan
> Cc: towertalk at contesting.com
> Subject: Re: [TowerTalk] optimum vertical length
> 
> 
> jimlux wrote:
> > 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
> 
> Correction... the FCC specifically rejected a particular limit.. They 
> had received comments prior to the rulemaking recommending the BOCA 
> building code which says that permits are not required for structures 
> less than 12ft above highest point.
> 
> > 
> > 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?
> > _______________________________________________
> > 
> > 
> > 
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