Topband: insulated vs:bare radial wires

[W8AV at aol.com]

Jim:
 
When you are burying radials for a vertical antenna, you do not need to  
tune them.  Just make them as long as you can (not to exceed 0.4  wavelengths) 
and you are done.  The 0.4 wavelength number comes from  research done many 
years ago and published in the Proceedings of the IRE.   It shows that the 
amount of radiation efficiency that you gain by going longer  than 0.4 
wavelengths is not worth the trouble.
 
If you can not get to 1/4 wavelength in some directions, add extra short  
radials in that direction.  Your radiation efficiency in those directions  
will be lower so adding more radials will help to compensate for that.
 
The only time you need to tune a radial system is when it is elevated above 
 the ground.
 
Hope this helps.
 
 
73.................de Goose, W8AV