i'm not sure .64 is even relevant, even to the hy gain penetrator 500. in 3 manuals and vintage advertising on cb tricks, nowhere does hy gain claim the penetrator is .64 wave, infact on all 4 pieces of documentation from hy gain they claim its a full size 5/8 wave. don't take my word for it, check it out on cb tricks.
At 27.385MHz my Hy-Gain Penetrator at:
X = 0, 1:1 SWR = 274"
Average circumference - 2.5"
Unused .5" of radiator below feed point for bolt hole strength
--> 274" + 2.5" - .5" = 276" electrical, at .999 velocity factor of air.
11811* ÷ 27.385 = 431.3" x .64 = 276"
*speed of light
Notice anything similar there? It's clearly a .64λ.
In a day when everyone was touting the performance of the 5/8λ design, why would a company's advertisers be so obtuse as to offer anything else, except what was popular; a "5/8λ"?
Look at all the silly negative posts in just the last 3 months about the Sirio Gain Master being just another snake-oil big stick, or another fiberglass POS, etc..., some even coming from intelligent Amateurs who should know better.
People tend to disbelieve and shy away from anything new while following the pack, and Hy-gain obviously knew it.
No one wants to be the guinea pig until someone else takes the risk first and proves it for them.
Just because Hy-Gain decided to name it a 5/8λ or a 211/330λ or a blue flamingo doesn't change the physical or electrical properties, and it is a .64, like it or not.
i've never heard .64 mentioned in any other radio/tv publication except for cb, which suggests to me its just another piece of bullshit hype marketing, most likely from dealers as from what i can see it definately isn't being claimed by hy gain.
I posted only a few of the .64λ Double Extended Zepp websites, there are many more, and each is specifically referring to a .64λ, even though some might not be quite intelligent enough to actually put 2 & 2 together and do their own calculating.
Some of those websites obviously used a velocity factor in their calculations but failed to mention it.
- I'll address that in more detail in my reply to SW.
as for radials cancelling out the bottom 1/8 wave radiation, surely the radials would have to be more than 4 feet above the feedpoint, not 12-14 inches for that to even be contemplated, as it has 4 equal sized radials at right angles then cancellation from radials opposite each other would prevent radiation from the radials which if i'm not mistaken radiation would be required to cancel out radiation from the radiator bottom 1/8 wave which is out of phase.
If the radials were to cancel all of the bottom 1/8λ inverse current they would certainly have to be mounted at a point 4.5' up the radiator, but as Shockwave already pointed out in his silly rant, and according to him that would not work.
If that's true, I imagine Hy-gain may have tried that and found that 4.5' wouldn't work, and that 2.25' wouldn't work, and that 1.125' wouldn't work, but that 11" would work so instead of bottom-mounting the radials as did many others, like A/S on their Jam Ram, Hy-gain chose to use them in an application which helped to both lower the TOA and add gain to their .64λ Penetrator which they chose to call a "5/8λ", no doubt for marketing purposes.
another thing that strikes me is nearly every antenna be it 1/2 wave vertical (silver rod) or 5/8 wave vertical uses the exact same radial/bracket arrangement,including many ham and commercial antennas, yet i've never seen one manufacturer claim it made the slightest bit of difference in over 30 years of radio, i find that staggering seeing as nearly every other aspect of antennas has at one time or another been claimed by the deluded to improve things over their competition.
The metal is there for all to see. The math is there for all to see.
The feed point is only .5" up from the bottom of the radiator, the RF gets to the upper radiator somehow, you tell me how they designed it to, miraculously, amazingly, mysteriously prevent the bottom 11" of RF from radiating without a canceling Vector basket or some other form of radiation prevention?
Just a wee sprinkle of some magic Shockwave-Faraday dust, perhaps?
i'm also certain if it did provide any gain it would have been the bracket style used on the A99 so that radials could be added easily to improve the 9.9dbi gain claimed by solarconmen.
Perhaps this will help to clarify why:
There is no inverse current in a bottom-fed ½λ radiator.
i'm sensing a lot of snake oil on this penetrator 500 (probably more out of sentiment than reality), i doubt very much its any different to any other 5/8 wave apart from maybe tiny gain from having a better quality/less lossy coil than other antennas, but i doubt very much even if that was the case that it would be measureable without some very sophisticated test gear and an anechoic chamber.
this is just my own personal opinion.
op: