The above clearly indicates the fact that even at a simple level, we cannot IGNORE THE PHYSICS. You can't just brush it aside. Here's an illustrative thought experiment. Take a driven element and a 1/8 wave separated parastic. Make the parasitic slightly smaller than the driven and then excite the driven at resonance. You will get some--but not complete-- constructive interference in one direction, and nearly complete destructive interference in the other. Now: cut the parasitic to exactly the same size as the driven--what happens? Its still 'out of phase'--partially --because the baseline time delay offsets a wave generated by the parasitic (and phase reversal from re-radiation). BUT the behavior of the first case is not replicated---ask yourself why. Finally, make the length of the parasitic slightly LARGER than the driven. Now the case of 1 is REVERSED, even though the element spacings and positions have NOT changed. So we know that re-radiation causes a phase reversal, but case 1 and 3 BOTH already incorporate said phase reversal (and baseline phase offset), with vastly different outcomes. The strikingly different outcomes incorporate THREE physical--as in physics-- attributes in producing the interference effects...1) baseline offset phase delay; 2) phase reversal in re-radiation; and 3) phase effects (lag differences) from reactive differences, in this case capacitive vs inductive (or visa versa) of the parasitic in cases 1 and 3. So, describe what happens in CAPACITIVE REACTANCE vs INDUCTIVE REACTANCE with PHASE LAGS. If you do not have even a simple understanding of this ---simple is the operative word-- then you cannot have even a remote understanding OR APPRECIATION of how antennas work in the amateur radio service. And that is the point here....it is important to know AND FUN to understand. No college course needed. No textbook needed. Just you--as a HAM--and your innate curiosity. All you need to understand is interference and phase--and what phenomena cause phase differences. Simply. 73 Chip W1YW
I'm still waiting for the "apples to apples" comparison of the dipole and the hex-beam at 5/8 wavelength above earth. How about modelling both antennas at 5/8 wavelength above earth for each of the bands on which the hex-beam is designed to operate? Maybe the hex-beam has some fantastic gain on some band other than 20M. So far, the data seems to suggest that the hex-beam has from 2.5db to 2.7db of gain over a dipole on 20M. This difference would be barely discernable "on the air".
That 2.5db gain figure for the hex-beam falls far short of the 5.5db gain that you cited in an earlier post.
I cited 5.5dBi in free space. I then modeled it to show the gain over earth. It has on the order 2.5dB-3dB performance over a dipole in a similar setup. This is ignoring the benefits of the directivity which greatly reduced interfering signals. I will gladly model both the exact configuration, but I am not sure you are willing to accept facts. You have latched onto a single website and I asure even the owner of that website would tell you that you are mistaken.. you may still not believe it
You seem to want to avoid modelling these antennas, and instead, attack my character and the work of a highly respected individual who has taken the time to publish his information for the benefit of anyone who is willing to learn. The facts are what I seek, I want to ignore the myth and hype and old wives tales that are in abundance. I will gladly admit if I am wrong, but, so far, you haven't proven me wrong. All you've done is tap-danced around the issue. My contention is that the hex-beam doesn't provide very much gain over a dipole when both antennas are at the same height above earth. Your latest model shows 2.44db of gain for the hex-beam over the dipole and an insignificant one degree lowering of the main lobe. This proves my contention that the hex-beam is only slightly better than the dipole, it's certainly not a "flame thrower". Yes, there is a little more directivity and, of course, some front to back ratio, but I wouldn't consider it to be in the category of "greatly reduced interfering signals". Model the hex-beam and the dipole at 5/8 wavelength over earth, that's 50 feet on 20M, 30 feet on 15M, and 23 feet on 10M. My bet is that you will not see 3db of gain, even at the design frequency. The gain and directivity of a parasitic array falls off rapidly and significantly as you deviate even 2 or 3 percent from the design frequency. Without changing the length or spacing of the elements, model the hex-beam at the top and bottom end of the bands and see how the gain and directivity degrade even lower from its already mediocre performance. Merry Christmas
Here are models at three frequencies across 20m all at 50 ft since that is what you requested. Why do you not model them yourself since you are in a "search for the truth"? The consistently show about 2.5dB of gain. You say that is insignificant, but when coupled with the rejection of off axis signals, I promise it is a significant performance upgrade. I have certainly not tap danced. I have modeled everything you have asked me to model. Merry Christmas
I don't model them because that work has already been done and published by others. You called their work into question, that's why I asked you to model it for yourself, not for me. I did ask for 15M and 10M models, which you haven't done, but nevermind, I think it has come down to a matter of opinion about the significance of a 2.5db improvement, and we all know what opinions are like. 73
As my last comment in this thread, I would encourage you to reach out to W8JI and get his feedback on this since you seem to value his opinion. I will try and find time tonight to model the other bands and post them
Just get something in the air. If you take the time to do the math/physics it might just work like you want it to. If you don't - good luck. future 17m dipole... 73 and Happy New Year ! RJ Maybe my 2019 New Years Resolution should be "DO NOT REPLY TO OUT-OF-CONTROL POSTS ON QRZ.COM". At 17 pages - this one is OUT-OF-CONTROL.
