The other thing that K5IU was clear about is that the ground under the
antenna is the dominant factor in performance regardless of the radials you
use.
If you have really low conductivity soil under the antenna, even if you
mount a vertical on a 1/4 wavelength radius copper disc, essentially an
infinite number of buried radials, you are going to get poor performance.
Elevated radials will be as good or better in that situation, and are less
work, but a high dipole, over poor soil, will be equal or better.
If you have really high conductivity soil, a modest number of buried radials
or a set of 4 1/8 wavelength elevated radials tuned with an inductor will
probably give you good performance.
If you are over salt water, a single resonant radial will work very well.
BTW the ground conductivity maps most of us have access to, like
https://commons.wikimedia.org/wiki/File:United_States_Effective_Ground_Condu
ctivity_Map.png , are from data averaged over a large area and any given
location within an area on the map may vary widely from the average. The
perfect QTH is a hill of salt water, sloping gently in all directions.
73 John N5CQ
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|