any height will help with an antenna, especially on the higher bands...15, 
12 and 10 and 6M if the vertical has that band.
a radial system at the bottom of the tower will help even more, though if 
the tower is a quarter wave or better on the bands you wish to operate, that 
will provide an atiquit counter poise...
if you have a 65FT tower, that will be a quarter wave on 40M and you could 
operate without radials, though having 16 65 foot radials at the bottom 
would help allot on 40.
does the zero five 43F have a built in counter poise system? or is it 
similar to the gap antennas and works on a vertical dipole design?
even with built in counter poise, having ground radials will increase 
efficiency.
a vertical metal tower will increase efficiency beyond a basic roof mount 
with no radials.

also, the program CWGet seemed to be pretty screen reader friendly the last 
time I used it.

73
Colin, V A6BKX
----- Original Message ----- 
From: "Michael Ryan" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Monday, March 22, 2010 12:01 PM
Subject: tower mounted vertical VS ground mounting...


> Hi list:=20
>
> Just looking at some specs of a Zero Five 43F vertical.=20
> It says that it can be either ground mounted or on a tower.=20
> Can understand ground mounting because most verticals, to function =
> properly, require a ground radial system with a min of 16 radials cut =
> for the band you want to operate.=20
> So, why would you mount this kind of antenna on a roof or tower?=20
> If you add height, could you reduce the radial requirements?=20
>
> Oh, before I run:=20
> Still waiting on some digipan and window eyes 6 assistance and a =
> recommendation on a screen reader friendly CW decoder.=20
>
> 73:=20
> Mike=20