Topband: Coax Shield vs. Ground & elevated radials

[Sinisa Hristov]

Telegrapher9 at aol.com wrote:
 
> When elevated radials are mentioned they are often full 90-degree radials.
> The low impedance presented by the radials makes decoupling the coaxial cable
> shield easy.


Unfortunately, not.

As an EZNEC computation can show, even with a large number of elevated
90-degree radials, there can be a lot of common mode current, and balun
requirements are much stronger than for, say, a horizontal dipole.
This is due to the lack of symmetry in the system.


73,

Sinisa  YT1NT, VE3EA