Like many in urban Southern California, we live in a lot not big enough to raise antenna farm, and if we did, HOA deed restricts construction of tower and/or decent antennas. That’s the situation for me for almost all of my ham life, so I have been always experimenting with new ideas, to see if I can get any better. I have tried several trap verticals, full size and shrunk dipoles, odd balls like end fed Zep and Off Center fed Carolina Windom, etc., etc. Some of them stayed around for a few years, others, just a few months. I have never been fully satisfied, it’s just me. They say good dipole antenna is hard to beat. But my experience with them were not so rosy, most likely because I could not raise the antenna high enough (only 7 or 8 meter at most) to be effective. In my attempt to be invisible, using relatively thin gauge wires (14 ~ 18 Ga) did not help, either.
After much soul searching, I built a full size 40m quarter wave vertical, a fiber pole as the support. I actually liked this antenna very much; I never had such a good result on 40 meter band before. But as it was, I could only use it for 40 and 15 meter band. Other bands were possible only through the tuner. That prevented me from understanding how the antenna is really working when tuned. And it restricted the transmission power level; not that I do that often but I do own a linear amplifier and would like to leave that option open. Since 20 meter is my main DX band, I decided to add a second quarter wave element just to support that band. That worked fine, but other bands remained restricted.
Then one day it just occurred to me. After evaluating wave lengths of all relevant HF ham bands, I figured out that three elements of strategic lengths lets me operate on all HF bands 40 meter and above, and some bands actually can expect some gain! And the structure is not complicated at all.
I am calling this custom vertical a Mission Viejo Special, commemorating deed-restricting city USA. It is not-so-visible but of good performance (wide bandwidth, good radiation efficiency, low radiation angle), very suitable antenna for the area.
I welcome any questions, comments, suggestions concerning this antenna design and implementations. Click here to email me.
Tak Asami / W6Si
(Originally posted: August 22, 2014)
Duplication and experiment by any individual ham operator is encouraged. But with any antenna project, be extremely careful and pay attention to the mechanical integrity of the structure. The author discloses as much information as practical, but the ultimate responsibility lies with each practioner..
If anyone wants to commercially productize this design, please contact me prior to doing so.