What then of combining both fractals and curved perimeters? When I tried my 20M 14ga TNN wire fractal yagi (your call was mentioned in the design), I had essentially sparrow flatulence as gain; no different than my monopole long wire. I wonder if a fractal perimeter can be wave-guided not unlike a yagi's reflector/director with a loop approximating the fractal, both as director & reflector, simplifying design. I need more coffee. The measurements were by report and observation from my sycamore tree, rather than the confines of a meaningful test lab, and I recognize the anecdotal nature of them. This said, I'd like to find combos that defy legendary designs.
Nope. I can't take credit or blame for others mistakes or errors, let alone successes. Which design are you referring to. Picture? Could be something simple to fix it. Why would I publish or make an antenna that is unidirectional --without gain? Anyway, you can email me, so that the focus of this thread is the OP. 73 Chip W1YW
I would like to add a short comment: The mathematics was only a part of the purpose of the paper, a summary statement . For me the receiving power/ability was much more of an interest. On the chimney I put a 23 feet marine whip antenna to be driven by the AT 130 ICOM tuner and the ICOM 7610 . This was my reference antenna system . For accuracy reasons I used an R&S calibrated test receiver model ESMD and/or the PR 100 The test loop antenna showed a smaller signal as expected and followed the calculations. The loop also acted as high Q input filter The mobile whip antenna was another test case , less signal then the 23 feet vertical. Actually the loop at 14 Mhz was about 3 dB stronger at the receiver place . Again this requires a calibrated test receiver. As the active antenna was much smaller then 12 feet there was no surprise the the signal received was less , but followed the math. prediction. I had hoped to make this clear but may be because of overwhelming calculation that got lost. 73 de Ulrich
Hi Chip, Hope you are good. I appreciated your full explications here. I would like to ask you something, not sure if fully related to the above statement, but no one knows the answer. If you place a cubical quad, same boom length, same height, same location, by a Yagi. Quad will outperform Yagi 90% of the time. Running antenna simulations on NEC4.2 shows same, or quite similar, gain and F/B figures. Why results does not match simulations? I am not sure if it's related to antenna's footprint, or it's related to polarisation, or what. You got some cubical experience, hopefully you can help here. Thank you in advance. 73, Maximo - EA1DDO
Hi Maximo, Ulrich and Kai have an interesting thread going, so I am trying to divert off-topics to emails Its rare that Ulrich gets on QRZed and I think its important that the community have access to him. Antenna sims are only as good as the initial conditions and 'meshing' (sampling) allow. I suspect, however that in your A to B comparison, the vertical (elevation) power pattern differential may occasionally favor a quad Yagi, even though the PEAK gain and F/B are similar . We tend to lock in on very low launch angles as the only measure of 'goodness ' to Yagis, when on many circumstances the height of the antenna and propagation changes during the day, favor higher (that is, away from the horizon) elevation angles for the DX. IOW the best path at a given time to a given DX may not be the lowest elevation coverage of the Yagis. My impression is the quad Yagi has an edge in that case, but do not have the power patterns in front of me. 73 Chip W1YW
Ulrich It looks like this paper is for IEEE publication. I would recommend that you get Dr. Stephen Best to do a critical review for you. He is a recognized expert on small antennas and an IEEE fellow. Dr. Tim
Hi Dr. Tim, I am afraid this paper with all the mathematics, measurements and pictures is too readable and not too clinically dry enough. Maybe if you put a good word in for me it may work.. Thanks, Ulrich
Let's not forget the simplistic reason for the difference. It is not "at the antenna," but likely the near and far field environment. An E field is very easily perturbed and absorbed, whereas not so much with an H field. The matrix of loops gets through the trees in the forests and structures much better than the Yagi-Uda or simple dipole or vertical. Fractallian a winner? Well with all the abrupt shifts in E field, well, be the judge. At least practically speaking.
Maximo is referring to electrically large--one wavelength electrically-- quad loops. These have two current maxima in phase, separated by 1/4 wave and co-planar. Not 'magnetic' loops, which are very electrically small. There are no fractals in his discussion.
