Here you can see the 1/2 wave over a quarter wave antenna, with the 5/8ths
wave and the simple 1/2 wave center fed antennas in the background:
wave and the simple 1/2 wave center fed antennas in the background:
Note: picture is of first prototype,
without the fiberglass stabilizer
bars attached. The new version
is made out of black fiberglass
with stabilizer bars attached
without the fiberglass stabilizer
bars attached. The new version
is made out of black fiberglass
with stabilizer bars attached
Here is the 1/2 wave over a 1/4 wave antenna tree-mounted, with the wind blowing:
The Pros and Cons of the 1/2 wave over a 1/4 wave antenna:
The half wave over a quarter wave is better than any other half wave antenna (including an Antron 99..),
because its truly a 1/2 wave over a quarter wave, meaning both portions of the antenna actually do radiate!
The Ground Plane at the bottom, creates two significant perks for the 1/2 wave antenna. First being, is that it
actually lowers its angle or radiation, and second being, is that it also lowers the overall impedance of the
antenna from 3,000 to approximately 850 ohms. This means less matching is needed, to achieve the
desired 50 ohm impedance. This makes it easier to reduce matching network/inductor loss, when
performing the impedance matching transformation.
The 1/2 wave can be mounted on a tower, a pipe, or even tree mounted. It also has a great bandwidth, and
with the 1/4 ground plane element underneath it, it also achieves a decent low angle of radiation gain thats
superior to conventional 1/2 wave base antennas. Unlike other half wave 18 foot CB antennas, this 1/4 wave
section is truly an active part of the antenna, and will affect SWR and performance significantly if it were to be
removed.
I used an optimum parallel matching technique, to efficiently match the antenna to 50 ohms. The drawback
of the antenna, is that it requires both an inductor and a Hi-Q transmitting capacitor to achieve such
efficiency, which also limits its power handling to 5000 watts approx. Its nearly impossible to find affordable
transmitting capacitors that can handle more than 5000 watts. The capacitors I use are ceramic, and are
rated to handle 15,000 "peak" volts at 15 amps of sustainable RF current, which equates to about 5000
watts max.
because its truly a 1/2 wave over a quarter wave, meaning both portions of the antenna actually do radiate!
The Ground Plane at the bottom, creates two significant perks for the 1/2 wave antenna. First being, is that it
actually lowers its angle or radiation, and second being, is that it also lowers the overall impedance of the
antenna from 3,000 to approximately 850 ohms. This means less matching is needed, to achieve the
desired 50 ohm impedance. This makes it easier to reduce matching network/inductor loss, when
performing the impedance matching transformation.
The 1/2 wave can be mounted on a tower, a pipe, or even tree mounted. It also has a great bandwidth, and
with the 1/4 ground plane element underneath it, it also achieves a decent low angle of radiation gain thats
superior to conventional 1/2 wave base antennas. Unlike other half wave 18 foot CB antennas, this 1/4 wave
section is truly an active part of the antenna, and will affect SWR and performance significantly if it were to be
removed.
I used an optimum parallel matching technique, to efficiently match the antenna to 50 ohms. The drawback
of the antenna, is that it requires both an inductor and a Hi-Q transmitting capacitor to achieve such
efficiency, which also limits its power handling to 5000 watts approx. Its nearly impossible to find affordable
transmitting capacitors that can handle more than 5000 watts. The capacitors I use are ceramic, and are
rated to handle 15,000 "peak" volts at 15 amps of sustainable RF current, which equates to about 5000
watts max.
More to follow coming Soon
My "true" 11 meter 1/2 wave over a 1/4 wave aerial antenna
All antennas are tuned
and checked for a low
SWR, via the trusty MFJ
SWR Antenna Analyzer.
and checked for a low
SWR, via the trusty MFJ
SWR Antenna Analyzer.
My highly efficient Hi-Q
coil, is about 10 times
than the IMAX 2000 coil
coil, is about 10 times
than the IMAX 2000 coil
An example of a
competitor's (IMAX 2000)
coil matching network
competitor's (IMAX 2000)
coil matching network
system, next to the
competitors'
competitors'
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