design: Trap spool contains 10 turns of copper wire
diameter in diameter of 2-mm, form of the spool has diameter of
60-mm, distance between turn is 4 mm. The LC circuit should be
tuned to frequency of 14.2-MHz. It is possible use a GDO for the
tuning. A capacitor at 3-pF is bridged to trap capacitor when
the trap is tuning to the resonance. The capacitor is simulated
a stray capacitance of the antenna sections. It is necessary to
safe trap capacitor from the atmospheric effect.
tuning: At first, with the help of a GDO tune trap
to 14.2-MHz. The circuit tune separately from antenna. At second,
tune length A to a minimum SWR in 20 meters. At third tune length
of the Section B to minimum SWR at 40 meters.
notice for vertical multi range trap antennas
For a proper work a vertical trap