[TowerTalk] optimum vertical length

Joe Subich, W4TV lists at subich.com
Mon Jun 1 06:59:21 PDT 2009



> So, then, what about this trade-space (again, in the world of fairly 
> inconspicuous antennas)..
> 
> You could have a ground mounted vertical (of whatever length)
> 
> OR
> 
> a shorter vertical sticking up from the roofline, with a bunch of wire 
> as a counterpoise/ground screen on the roof.  (or a vertical dipole)

In my opinion, the "optimum" solution consists of two antennas.  The 
first would be a roof mounted 22 foot vertical (either a "half size"  
43' vertical with tuner or an R5/AV-620) for 20-10 meters and a ground 
mounted 88' vertical (or inverted L - up 55 out 32) for 160-30 meters. 

In this case "optimum" is defined as a minimum effort/impact solution 
that provides reasonable performance on all bands.  

73, 

   ... Joe, W4TV 
 







> -----Original Message-----
> From: towertalk-bounces at contesting.com 
> [mailto:towertalk-bounces at contesting.com] On Behalf Of jimlux
> Sent: Monday, June 01, 2009 9:27 AM
> To: jim Jarvis
> Cc: towertalk at contesting.com
> Subject: Re: [TowerTalk] optimum vertical length
> 
> 
> jim Jarvis wrote:
> > Jim,
> ".
> > 
> > Regardless of the electrical length of the antenna, though,  getting
> > it up high and in the clear
> > is the important factor.   A 40m vertical dipole plays 
> amazingly well  
> > on multiple bands, with
> > a tuner, if you can get the high current portion of the antenna up  
> > 50' or so, in a tree.
> > 
> 
> 
> 
> So, then, what about this trade-space (again, in the world of fairly 
> inconspicuous antennas)..
> 
> You could have a ground mounted vertical (of whatever length)
> 
> OR
> 
> a shorter vertical sticking up from the roofline, with a 
> bunch of wire 
> as a counterpoise/ground screen on the roof.  (or a vertical dipole)
> 
> 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?
> 
> 
> Assuming you're not at the beach, etc.  It seems that getting the 
> feedpoint up in the air will reduce near field losses from 
> the soil, at 
> the expense of incurring losses in your groundplane/lower half of the 
> antenna.
> 
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> 
> 
> 
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