Perhaps the lack of difference in the VSWR bandwidth of the two designs explains why the Cushcraft 402CD/XM240 designs go to the trouble of using capacitance hats after the loading coils. capacitanc
I agree with Dave. We had a similar discussion about this (using monopoles) nearly 20 years ago in the rec.radio.amateur.antenna forum. I wrote a little paper at the time; I see it's available at:
I think we all know why -- hardly anyone bothers to study stuff. 73, Jim K9YC _______________________________________________ _______________________________________________ TowerTalk mailing list To
On 4/28/2020 6:50 PM, David Gilbert wrote: Whether NEC accurately models the current isn't the point. You don't need a model to know that if you push the coil out away from the center the portion of
https://www.qsl.net/n7ws/Loaded_Antennas.pdf Dan, AC6LA _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com
Agree on all of that, which is why I agreed it isn't a dominant effect. And of course you and K6STI have a good point about the additional wind loading of mid-element coils. Every commercial coil lo
Excellent post Dave. I found this to be an interesting towertalk discussion with some initial surprising model findings. I do recall modeling a loading coil far out on the element and found it to be
Wes N7WS I think, though, that the whole "short vertical" thing (typically in the context of vehicle mounted antennas) is a much more extreme case than a loaded 40m, where the elements are nearly fu
Agree on all of that, which is why I agreed it isn't a dominant effect. And of course you and K6STI have a good point about the additional wind loading of mid-element coils. Every commercial coil loa
Of course. On 4/29/2020 6:21 AM, jimlux wrote: On 4/28/20 9:35 PM, Wes wrote: I agree with Dave. We had a similar discussion about this (using monopoles) nearly 20 years ago in the rec.radio.amateur
The forward gain difference between my single-coil and two-coil models is 0.02 dB. This is with no coil losses, whose difference might easily overwhelm a small directivity difference. But I restored
Physical bending of the tubing is not necessary. By using mounting plates with isolating Stauff clamps at the needed angle as element holders straight elements can be used. 73 Peter The forward gain
That seems a little high for OWA gain reduction, especially with modern designs. I believe the theory is that a conventional a Yagi has losses from the match and a OWA of course has no match losses.
Here are the four AO (.ant) models described on the above page converted to AutoEZ (.weq) format, with the AO variable names used in Brian's models converted to AutoEZ variables: https://ac6la.com/ad
How much loss is there in a conventional Yagi match ? From what I understand the OWA has about a .50 dB loss in forward gain compared to a conventional Yagi. If a conventional yagi has about the same
There is no reason a yagi match would loose 0.5dB. By lengthening the boom for OWA the gain can be kept the same as with the conventional yagi. 73 Peter How much loss is there in a conventional Yagi
I have used OWA Yagi's for over 20 years, so lots of real experience - I would never install anything else here. The wide VSWR bandwidth is really a great feature. I have four legacy beta matched 10
Peter, Thats good to hear. Thanks Bob K6UJ _______________________________________________ _______________________________________________ TowerTalk mailing list TowerTalk@contesting.com http://lists
Tim, Thanks for the info ! I am thinking about fabbing a 20M OWA. I have the materials and more than enough time now with the shelter in place, hihi. Bob K6UJ ________________________________________
Indeed, I built a 7 element 10m and a 6 element 15m some years ago and converted 2 of my KLM yagis to OWA last year and 4 other KLM to follow during the summer. Also converted HyGain yagis to OWA suc