Topband: radials for verticals

[Tom Rauch]

Hi Frank,

> I sort of understand why.  Vertical antennas may be the only
> reasonable DX radiator for topband.  Actually, verticals are
> probably a good alternative to beams on the higher frequency
> bands.  The only problem is the radial thing.

Verticals also have more Fresnel zone losses, because the area 
where pattern is being formed involves a large area of the earth and 
things on the earth around the antenna. That isn't as much of a 
problem on topband, but it is a major issue above 40 meters.   

> I know that the GAP antenna is a linear loaded, vertically
> polarized dipole.  No radials required.  Why isn't there
> more traffic on it being used as a solution?

Because it (like many "no-radial" or "few-radial" vertical antennas) 
has horrible efficiency, for a number of reasons. 

> understand why a linear loaded solution to make the
> mechanical problem go away has not received much interest.

Linear loading is no more efficient than a lumped component. As a 
matter of fact all things equal (loading device wire size and effective 
loading location) it is less efficient than a lumped component.

The only way to decouple a vertical from the lossy earth below the 
antenna is to move it 1/4 wl or higher above earth or to lay down a 
mess of radials. There is no other solution. It would be nice if there 
was.

Many people live quite well with a less-than-ideal antenna, and 
make lots of contacts. Do the best you can.

>73, Tom W8JI
w8ji@contesting.com



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