[Top] [All Lists]

Re: [TowerTalk] elevated radials vertical

To: "Jim Brown" <>,<>
Subject: Re: [TowerTalk] elevated radials vertical
From: "Tom Rauch" <>
Reply-to: Tom Rauch <>
Date: Fri, 8 Jun 2007 19:33:03 -0400
List-post: <>
> At my present QTH in CA, a ground mounted, top-loaded 
> vertical with
> 40 radials 70 ft long works VERY well on 80 and 160. But a 
> ground-
> mounted quarter wave vertical for 40 meters with that same 
> radial
> system works very poorly. As Tom has suggested, my 
> judgments as to
> what works and what doesn't are based on actively 
> switching during
> contests between these antennas and high dipoles. When an 
> antenna
> is working well, the differences between it and a 
> reference will
> vary depending on what vertical angles are propagating 
> between you
> and the other station, and which antenna has the advantage 
> will
> vary from hour to hour, and from one distant QTH to 
> another, so you
> need a lot of observation to make a good evaluation.

I find the same thing here Jim, but I find it with a 
vertical at any reasonable height on 40m or above.

My OPINION is the ground losses in the Fresnel zone are low 
enough on 160 and 80, but the ground outside the area of the 
radials sucks-up signal on 40 and higher.

Now if I stick the vertical 150-200 ft up in the air it is 
very competitive on 20 and higher with a dipole at a similar 
height. I'm just not sure where the breakover point is.

As an example I have a dipole at 300 ft on 160. The ends of 
the legs are at about 250 feet, so it is pretty high. 
Despite years of blind tests the dipole is only very rarely 
better than the omni vertical at any distance, and this is 
broadside to the dipole. 90% of the time the vertical is 
better, several percent the dipole is tied, and only on very 
rare conditions (a few days a year)  is it better. On 80 it 
is stacked slightly in favor of the dipoles. On 40 a dipole 
consistently beats any vertical, except one mounted on top a 
200ft tower.

But we all have to use what we have to use to get by. Some 
people can't install high dipoles, so the vertical is better 
thn no antenna no matter how poorly it is installed.

73 Tom


TowerTalk mailing list

<Prev in Thread] Current Thread [Next in Thread>