[disclaimer]
I provide the following link and it's content for information purposes for those that are in any way curious. That my experience with the A99/Imax2k and their clones mirrors that of W8JI, Tom Rauch is coincidental, or not ...
[/disclaimer]
https://www.w8ji.com/end-fed_vertical.htm#IMAX
[opinion]
Anyone interested in furthering their education in radio communication should bookmark his pages. The answers to many questions regularly asked here are within Tom's pages.
[/opinion]
"
Most of the radiation is up in the sky at a high angle. The angle is so high, it is even useless for skywave.
This is a NEGATIVE gain antenna at low angles. A 1/4wl ground plane would seriously outperform the I-MAX 2000 or any other 1/2 or 5/8th wl antenna that does not have a large ground plane.
This pattern is over real earth, where a conventional dipole has about 8 to 8.5 dBi gain. This antenna about -2 dBd gain maximum. It has negative gain over a dipole. The gain over a dipole at most useful angles for DX is about -10 dB....significant negative gain."
Even if we use the optimum feed line and mast length, here is the very best the end-fed vertical antenna will do is this pattern.
"
In this case we now have 2.67 dBi at 8 degrees elevation. This is actually an amount that is unnoticeably less than a perfect 1/4wl ground plane will produce! These severe common-mode mast and feed line currents make "no-radial" verticals extremely sensitive to mounting height, mounting structure, feed line length, and grounding. CB'ers for example often talk about grounding coax or changing coax length to match an antenna. If changes in mast length or feed line length or grounding affect the antenna pattern or SWR, it is an antenna design problem.
The gain over a dipole is now a few db at some really low angles, so it can be better than a dipole. At slightly higher angles for shorter skip, the dipole takes over and can be several dB better than the vertical.
This change is entirely the result of altering height and feed line/mast length!!! No antenna changes were made!"
The above content courtesy of W8JI, Tom Rauch.
Many thanks to Tom Rauch for his tireless experimentation and publication. Also thanks are due for his continuing to allow hot linking of his images .
I went to the trouble to offer opinion and post this information because full length whips are increasingly hard to find due to exorbitant shipping charges for length alone. Even suppliers for full length whips in glass or stainless have diminished to a handful . Once cut there is no going back. I was just trying to save a full length whip. Kind of a silly reason but I'm full of unique and obscure alternatives , when I'm not being a dick.
Apologies to Silver Devil and Staff .
