007, except of talking on these antennas my experience earlier was with mobiles. I only became actively interested in base antennas in the early 90’s after I got back into radio and several new high gain base antennas came on the market. Ads were making big gain claims that I had never experienced. I became curious and started to study and understand what I could of a complicated issue, and then to experiment and compare results.
It is ironic that you and I differ so much in our experiences and words. I talked about some rather nebulas topics regarding the effects of Earth and the soil under these CB antennas we use and compare. Again, It was my sole point to call attention to the fact that the theoretical chart for antenna gain I submitted was calculated and determined as though the antennas tested were positioned over an infinite conductive surface and to avoid the effects of Earth. And, you claim those effects are minimal.
The description of how these results were determined is listed right there in the captioned text of the each chart. The creator of the chart wanted to make it clear, regarding the distinction and to advise the reader about how the test was conducted. The words in the captions had a purpose.
At our level of understanding I realize that the topic of “Ground” and the affects of Earth on antennas may be a bit beyond our ability to determine or measure, and you raise a good point for why we raise our antennas as high as possible. But, it was the scientists involved with radio that made a singular distinction in considering too eliminate these affects of Earth in their determinations for gain---and they said nothing about height.
I consider this information as important distinction and you claim it is irrelevant. You say that due to the height we place our antennas the affects of Earth are negligible. I agree Earth factors are minimzed, but I'm not sure they are irrelevant. Even so---the numbers for gain that have been established as a standard are the same numbers you use, so no arguments up to this point, right?
It is my opinion that within some varying and reasonable range of height and location, that I find little overall real difference in performance between the CB 1/4, 1/2, 5/8, .64 wave antennas that we use and compare. You post you find lots of difference.
I record RX signals only and do not depend on TX signal reports. The differences I find vary a little depending on the location of the TX stations recorded. I test two of my antennas, side by side, and I record signal results from stations 8 – 60 miles away. You instead find 10 – 15 db or more differences between a 1/4 wave and a .64 wave antenna.
I do test all antennas at the same tip height based on the old FCC rule governing maximum heights for vertical CB base stations. I concede to the idea that maybe testing should be conducted with feed points as the same height. However, I have been told that when vertical antennas are actually tested on a test range, the antennas are all tilted over into the horizontal to make testing fair and easier to measure FS testing. If that is true, then my efforts to make height fair are due some consideration. I accept your arguments that this may be the difference we are discussing.
I can give you some links to these ideas that go all the way back to the ’20 and Stuart Ballantine, wrote “On the Optimum Wavelength for a Vertical Antenna over Perfect Earth,” if you like,
Thanks for your comments.
Excellent and thoughtful reply!
First, it sounds like you're making my argument for me when you mentioned that the very Scientists who gave us these gain figures (to use for workable comparisons) thought ground effects so minimal that they not only decided NOT to allow for it, but didn't even worry about specifying the height of the antenna above ground, as you mentioned.
It sounds to me like we are in agreement instead of debating...?
Also, when one compares one antenna's performance to another at their home shack, if it is a real-world comparison, who in the world is going to go purchase and install, (or plant) two or three different masts, towers, trees, etc. so they will be "Fair" about the comparison?
In the real world, one goes as high as po$$ible and then uses what they have as a supporting structure to place the antenna atop, - so who really 'gives a rip' if the tops or feed points are the same or not when one considers that one antenna design, by nature of it's design, (ie: Starduster, Astroplane) causes that antenna to be inferior due to it's very design providing inferior horizon visibility? (as in these cases in comparison to a .64)
That, in and of itself, in MY book is one MAJOR determining factor in the real-world performance comparison.
The idea is to find the best performer for one's station, NOT the best design
IF everything is
adjusted so any design
deficiencies are
equalized out, as that would result in a bogus comparison for everyone except maybe for someone on a mountain top, then they have such a height advantage they could run a 102" whip and probably still rule the county.
Please keep in mind, I'm referring to long range ground-wave performance when comparing omnis since a beam is usually preferable to a vertical for sky-wave DXing.
As far as seeing local differences between different designs, I recall when I bought my first dummy-load A99.
I had the Penetrator atop a 5-section telescoping mast and couldn't believe that ridiculous gain rating of 9.9dB on this new whiz-bang fiberglass antenna, but I HAD to try it just in case technology had found some new way of gaining efficiency.
I took the first A99 back because I thought it was defective since I lost so much performance. Stations who had consistently given me S-9+3 dropped to a weak S-7. I returned it, swapped it for another new one and same result.
I couldn't believe someone would not only lie about gain to such a ridiculous degree, but would even
offer such an inferior performing antenna.
That's ~2.5 S-units difference (over about 10-12 miles) between two (1/2 wave) A99s and a (.64) Hy-Gain Penetrator, both mounted at ~60', same radio, coax, days, etc.
One thing I noticed about your comparison parameters, you mentioned that you used two separate masts. In my opinion this is a no-no because of the possibility that the testing station might be skewed to a degree off to one side, thus providing for a potential null to one antenna whilst the other may be nearer to a peak in the sinewave propogation.
Except for comparing static-bleeding capability, I have NEVER compared two antennas performance under side-by-side conditions. I always use the same mast, coax, radio, day or time of day, etc.
73
