ETS-Lindgren 3142C Biconilog Antenna (Archived) - Manual (Page 8)

With the end plates attached to the Model 3142C bow-tie elements, the
equivalent dipole electrical length is increased, which decreases resonant
frequency and increases efficiency in the 20 to 60 MHz range. Similarly, the
regular bow-tie has a lower resonant frequency than an equal length single-wire
dipole. The T end plate option has its first resonance at a frequency where its
length is about 0.22 λ, a regular bow-tie at a length of 0.3 λ, and a tuned dipole at
about a length of 0.48 λ. Thus, at 50 MHz the 1.4-meter long end plate option
behaves as if a 2.8 meter tuned dipole. Cross-polar radiation is minimized
because current flow on one of the T end frames is almost completely cancelled
by the opposite-phased current on the other T end.
8 | Introduction
Archived 01/19/11