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shock. Keep your distance! As a suggestion, remember the 10-foot rule; when carrying and using
ladders and other long tools, keep them at least 10 feet away from all overhead lines - including any
lines from the power pole to your home.
Theory of Operation
The first L/C circuit generates enough reactance to bring the whole HF9V to resonance on 80
meters allowing it to act as an electrical 1/4-wavelength radiator. It also generates enough
capacitive
reactance to produce another discrete resonance at about 11 MHz.
The second, 40 meter L/C circuit generates enough reactance to resonate the whole HF9V allowing
it to act as a 1/4-wavelength radiator. In order to minimize conductor and I²R losses on 80 and 40
meters where the antenna is physically shorter than a 1/4-wavelength and thus operates with lower
values of radiation resistance, large-diameter self-supporting inductors and low-loss ceramic
capacitors are employed. Where the height of the HF9V is slightly greater than a 1/4-wavelength
on 30 meters, an L/C series tuned circuit taps onto the 40 meter coil for the extra inductance to pull
the earlier 11 MHz secondary resonance down to 10 MHz.
At the same time, a portion of the 40 meter coil is shorted out which allows the circuit to resonate
on 30 meters The addition of this circuit also produces additional resonances at 14 MHz and 28
MHz.
On 20 meters the entire radiator operates as a 3/8-wavelength vertical with much higher radiation
resistance and VSWR bandwidth than conventional or
trapped
antennas having a physical height of
1/4-wavelength or less. Because the 20 meter radiation resistance will be several times greater than
that of conventional vertical antennas, an electrical 1/4-wavelength section of 75 ohm coax is used
as a
geometric mean
transformer to match the approximate 100 ohms of feedpoint impedance on
that band to a 50 ohm main transmission line of any convenient length.
The HF9V operates as a slightly extended 1/4-wavelength radiator on 15 meters, a 1/4-wavelength
stub decoupler providing practically lossless isolation of the upper half of the antenna on that band.
On 10 meters the HF9V becomes a 3/4-wavelength radiator with considerably greater radiation
resistance and efficiency than 1/4-wavelength trapped types.
On 17 and 12 meters the coils act as
packets of reactance
which allow the entire radiator to operate
as a 1/2-wavelength or 5/8-wavelength vertical. Capacitance for these circuits comes from what
exists between the windings, the radiator and the capacitance hat.
On 6 meters the vertical wire, together with the adjacent section of antenna, form a short-circuited
1/4-wavelength transmission line which cancels current flow. At the lower, open end of the 1/4-
wavelength section a very high impedance is created the effectively divorces the upper part of the
antenna leaving the lower section to radiate as a 3/4-wavelength vertical.
