The interior of the VHF TW antenna essentially is a 50 ohm center conductor
against the ID of the pylon. Beam tilt is done by the location of the slots
on the pylon. The useful part of the elevation pattern of these antennas
is made very smooth (no sharp nulls), and it produces fairly uniform fields
near the ground from close to the tower base on out toward the radio
horizon.

The antenna was designed by RCA (Gibbsboro), and the design and production
facilities for it were acquired from them by Dielectric when RCA folded in
the mid-1980s.

As for the effects of beam tilt, Figure 1 in paper #9 at http://rfry.com
gives a graphical representation and discussion of what can be expected.

P1-8-3246 (1950s).

RF