Here's one that I ran across today and found interesting.
I wonder if they have built the prototype?
73
Jeff
I wonder if they have built the prototype?
73
Jeff
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$1000 PDL II clone
- Thread starter AudioShockwav
- Start date
Snake oil, besides that antenna gain is not in dB 
Yep Mike, that gain figure looks like slightly inflated DBi, I think a two element quad is a little less than 4 DB over a dipole.Snake oil, besides that antenna gain is not in dB
I used to have a PDL II many years ago and it was a decent little antenna for the size of it.
73
Jeff
They don't mention what the "array of high-performance features" actually are. "Co-Inductive"?? Like Mike said, snake-oil.
Here's another Quad option, minus the snake oil, all tubing, 50 ohm feed, 10 or 11m, by a real antenna company, at half the price.
https://www.dxengineering.com/parts/iva-18487-0021#overview
https://www.dxengineering.com/parts/iva-18487-0021#overview
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 around.
The loop spacing on the PDL -II is very close.
Maybe not bad in itself, but doesn't seem optimized.
I have seen a couple of sources claim that despite the driven loop looking like a full wave loop, its gamma match feed actually has it tuned or acting as a folded half wave element, with a quad loop reflector.
When these two antennas were designed, it was falsely thought that loop antennas didn't gain much by having more than two elements.
It has since been found that loop antennas gain as much from additional elements as Yagi antennas do.
Modern loop antennas use different size loops for the different elements.
The Maco Y-Quad (not the V-Quad) usually has a wider frequency range than the PDL-II and Maco gamma match might be slightly easier to tune.
I do like true quad loop antennas though.
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 around.
The loop spacing on the PDL -II is very close.
Maybe not bad in itself, but doesn't seem optimized.
I have seen a couple of sources claim that despite the driven loop looking like a full wave loop, its gamma match feed actually has it tuned or acting as a folded half wave element, with a quad loop reflector.
When these two antennas were designed, it was falsely thought that loop antennas didn't gain much by having more than two elements.
It has since been found that loop antennas gain as much from additional elements as Yagi antennas do.
Modern loop antennas use different size loops for the different elements.
The Maco Y-Quad (not the V-Quad) usually has a wider frequency range than the PDL-II and Maco gamma match might be slightly easier to tune.
I do like true quad loop antennas though.
Horizontal Full Wavelength Loops also make excellent Driven Elements for Yagis. Typically a bit quieter and 50ish ohm feedpoints when parasitic elements are added.
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 omni-directional.
A horizontal yagi often has more gain than a vertical yagi, but a vertically polarized full wave loop is bidirectional, which makes it start out stronger as part of a directional antenna than a vertical yagi element.
Have to disagree with you on that one. There are amateurs the world over working HF with ground-mounted and elevated verticals with multi-wire ground radials under them. And a thriving market of manufactured antenna choices out there.
7 3
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 was measured to the top, not the bottom.
Hygain used to advertise that vertical beams had more gain the horizontal antennas.
At the time, Hygain was selling horizontally stacked vertical yagi antennas, but the biggest difference was at low height, the horizontal antennas could suffer greater ground loss than the vertical antennas.
In space the gain is the same of course, but when a horizontal antenna is close to the ground in can suffer greater ground loss compared to a vertical antenna at the same low height.
Not really a gain difference, but great ground loss would decrease gain.
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 dimensions.
Note that three element beams have greatly increased front to back ratio, compared to two element beams.
dual loops do have slightly better front to back ratio than a two element yagi, which generally has poor front to back ratio.
This is the reason two element yogis are fairly rare for CB.
The two element loops were designed back when that was thought sufficient for loop antennas and the trouble to add another loop was thought not worth it.
So three element can make excellent front to back ratio.
More elements generally increase gain by narrowing the beam width, which isn't always desired.
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 dimensions.
Note that three element beams have greatly increased front to back ratio, compared to two element beams.
dual loops do have slightly better front to back ratio than a two element yagi, which generally has poor front to back ratio.
This is the reason two element yogis are fairly rare for CB.
The two element loops were designed back when that was thought sufficient for loop antennas and the trouble to add another loop was thought not worth it.
So three element can make excellent front to back ratio.
More elements generally increase gain by narrowing the beam width, which isn't always desired.
Thanks for the education, fellas! I have a six element Joe gun and I am thinking about putting it up vertical. The reason is, I only talk on 11 m. I do have a rotor and a hazer. I’m sure I would probably benefit more, running at horizontal! Curious, what’s your input?