Re: Topband: EZNEC prediction help

["Guy Olinger, K2AV" <olinger@bellsouth.net>]

Probably not so complicated as you might think.

In any event, any 1/4 vertical over anything other than salt water or 
a copper-plated ranch is going to lose a lot of power to ground loss. 
Typically -3 dB at best and perhaps a lot worse.

You can confirm this easily in EZNEC by changing the ground medium to 
salt water and watching the gain skyrocket.

Problem is basically that vertically polarized radiation does not 
bounce well off dirt. We overcome this in the very immediate vicinity 
by lacing the dirt with good conducting material, radials. But beyond 
that it's soak it up and energize the worms.

A max gain of 1.41 dB only means that in ONE direction and elevation 
anyway, the radiation is 1.41 dB better than an isotropic radiator in 
the same direction.

I don't use mininec ground for gain estimates any more. I think it's 
optimistic.

73, Guy

----- Original Message ----- 
From: "Rick Darwicki" <n6pe@pacbell.net>

The problem I'm having is understanding the various readings, mainly 
the 3d Max Gain and the average gain.

A full size 1/4 wave 160 vertical shows a 1.41 db max 3D gain and an 
average gain of -3.63. Used Mininec/medium ground.


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