RadCom Basics May 2022, Edition 28

18 RadCom Basics in close vicinity. And to add insult to injury, the coaxial cable may not even be at right-angles to the dipole. All these affect how the antenna will behave. With the antenna now unbal- anced, some of the RF current will travel down the coax screening braid (or shield). Now, I have to ad - mit I didn’t appreciate exactly how this happened with coaxial cable for many years so to quote from Peter Dodd,G3LDO’s Building Successful HF Antennas,‘Thanks to skin effect [2], which causes HF currents to flow only close to the surfaces of the conductors, the inner and outer surfaces of the coaxial shield behave as two entirely independent conductors’. G3LDO further added, ‘The currents on the centre core I1, and Figure 2: Reality - again showing typical electrical field lines Figure 3: Current flow showing cur- rents inside coaxial cable and due to skin effect, a separate current I3 to flow on the outside