On Fri, 09 Mar 2012 10:00:10 -0600, dave wrote:

On Fri, 09 Mar 2012 09:58:45 -0600, dave wrote:

On Thu, 08 Mar 2012 12:35:58 -0600, NM5K wrote:

On 3/8/2012 11:09 AM, dave wrote:
On Thu, 08 Mar 2012 08:51:20 -0600, NM5K wrote:

Also, ground mounted verticals will still need radials if the
antenna is to live up to it's expectations. And there is nothing to
stop one from using one elevated, if one uses resonant radials for
each band to be used.

My GAP Titan DX requires no radials; it is a center fed, asymmetric
vertical dipole.


Well, ground mounted monopoles in his case.. Being a "complete"
antenna, it's true that the center fed vertical does not require
radials for proper operation, but you would still likely show lower
ground losses if it were over radials. For instance, broadcast
stations that use 1/2 wave radiators still use a set of radials under
the antenna. Usually 1/2 wave radials, when used with a 1/2 wave
radiator. You will still see some ground loss with the ground mounted
1/2 waves over poor ground, but being as the max current point is 1/4
up from the ground, it's not near as severe as the ground mounted 1/4
wave where maximum current is at the base.

I don't think a ground screen is needed if you are 1/2 wave.

If you elevate a short vertical you only need a few "ground" radials
(think CB groundplane antenna), btw. My whole transmit antenna system
floats on my roof. The only "ground" is the panel where the RF goes
through the wall. I receive on a balanced 30m horizontal loop, also
floating except for the point of entry. I have an automatic tuner at
the feedpoint under the eave by my kitchen window. (FWIW) I have lived
here 14 years and have never seen lightning at the shack.

WABC on the rocks

http://www.musicradio77.com/transm.html

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