Owen Duffy wrote:
Such a design means moving beyond the simplistic explanation that such
antennas depend on traps acting like an on/off switch at the resonant
frequency, and that when they are resonant, the outboard conductors do
not exist.

The ARRL Antenna Book says the above is the "amateur"
version of how traps work. :-) They say "commercial"
versions use non-resonant traps.
--
73, Cecil http://www.w5dxp.com