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In theory, minimum ground loss is one wave length or higher above the ground, to the bottom of the antennas.
Best height for skip, reflecting off the ionosphere, is 1.5 wave lengths above the ground, to the bottom of the antenna.
A minimum height of 36 feet is result in the least ground loss...
Yes I know the 5/8 wave gain master, but Sirio also has fiberglass coaxial half wave antenna, that has a large coaxial RF choke at the bottom feed point to isolate the feedline.
It has a very wide frequency range for a coaxial half wave antenna.
It is basically a Big Stick with an RF choke...
There are antenna computer programs that predict antenna gain and pattern, with both horizontal and vertical yagi antennas.
I haven't looked at them and found out what they claim.
Vertical will be parallel with a mast and tower, where horizontal would be completely above those.
Hygain used to...
Until your picture, I didn't know the 16ft model had a coil at the bottom.
I don't think I ever saw that inside the 18.5ft version, but it had a small coil and a capacitor in the center, at the top of the bottom section.
It was a tiny component type coil, not as large as the one in the bottom...
There were at least two false theories about delta loop antennas in 1963.
These influenced the PDL-II and the V-quad.
One was that loop antennas didn't gain much by making them more than two elements.
The other was that both loops, driven and reflector, worked best when made the same external...
I mean for yagi antennas, for every type of antenna.
The vertical and horizontal reflectors on Monnraker type antennas is supposed to reduce the difference between horizontal and vertical.
Also many of these older CB antenna designs were designed back when the height limit was 20 feet and that...
Vertical full loops make good reflectors for Yagi antennas, because their angle of radiation is lower.
That's the main reason for the Moonraker type antennas.
Vertical is popular in CB and not so much in ham radio.
A horizontal dipole starts out as bidirectional, while a vertical dipole is...
The PDL-II was designed when antenna design didn't fully understand quad and loop antennas.
Both the PDL-II and Maco V-Quad had both loops exactly the same external dimensions.
This used to be thought to be important.
Later it was found that the reflector loop could be physically larger...
I often wondered how the inside of the 18.5ft ones and the 16ft ones differed.
I had an 18.5ft one.
I burned it up with too much power, but it had a very small coil and a capacitor in the center.
The RG-58 coax inside the bottom half, had "Shakespeare" printed on it.
Radio Shack later came...
A modulated carrier changes power by a factor of 4.
This can cause significant load changes on the radio to amplifier.
Some good amplifiers have a load balancing circuit, usually made of resistors, on their inputs, but many amplifiers have a gimmick high / low switch that switches out this...
Yes, I've seen some burned out finals in CB radios too.
Even without power reducing protection, they are designed to produce their rated power into a 50 ohm load and will produce less power as the. SWR increases.
Yes I know.
The drive power for most CB amps is lower than full power CB radios.
I had a HealthKit amplifier with resistors with coils around them, on the inputs of each tube that increased the required maximum power from around 50 watts, up to about 100 watts.
If running tube final radio...
Looking at the model recommended design amplifiers from the transistor companies, besides proper bias, they have an input circuit that has a network of resistors in it.
This because as an AM carrier is modulated, the impedance the radio sees changes and the input circuit resistors are there to...
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