Seems like everyone has an opinion about verticals. They either love 'em or hate 'em.
Those who hate 'em say the best helpful hint is to throw them away. Those who love 'em say
(and I count myself on this side) you just need to understand a few things.
Right off let me say that I am not the expert but I have studied a lot of documentation and I have done some experimentation. I have found some favorite resources. A lot of credit goes to my good friend Bill Rinker, W6OAV for getting me thinking about verticals during a trip to Dayton.
The light eventually came on for me and I put a small list of "revelations" together:
1. A big top hat (like the one in this picture) helps a lot. It raises the radiation resistance which makes a vertical easier to match and makes it more efficient.
2. Near field ground conductivity determines efficiency and far field, angle of radiation.
It's pretty obvious you need a good ground system but do you need as much as I have in this picture?
3. Since the near field determines efficiency, losses here are very important. Ground loss is one of those losses, and ground losses can be affected by the ground system. Soil conditions determine how many radials are needed to keep the near field losses at a mininum.
4. Soil conditions also affect the far field and the angle of radiation but we can't change that, other than to pick a location with good soil when we are looking for real estate.
5. Good traps don't waste significant power. Coax traps are not the best but they are not very bad.
6. Shortened verticals have the same radiation angle as a full size quarter-wave vertical, but shortened verticals are less efficient. Verticals longer than a quarter wave have gain.
7. Shortened verticals have narrower bandwidth and lower impedance.
8. "The radius of your ground system need only be as big as your vertical is tall". This statement has some doubters. Shortened verticals don't need a full-size quarter wave ground screen.
9. Low power Hustler coils radiate better than high power Hustler coils due to capacity coupling from their end caps, but it's barely measurable.
Ok, I've thrown out some statements here. Do I detect any skeptical thinking after reading this list? I'd like to reveal one of the authors who I believe is very expert and the one who has contributed many of the above statements. His name is Jerry Sevick,W2FMI and he is widely published. Dr. Sevick's works are a must read for any vertical antenna enthusiast.
I am also a devoted follower of Rudy Severn, John Kraus, Frederick Terman, Ward Silver, John Devoldere, Ron Prack, L.B. Cebik and many others I forgot to mention. These specialists have contributed greatly to my understanding and to the advancement of ham radio antenna practices.
If you don't recognize the name Jerry Sevick you might remember this antenna---the famous 6 foot 40 meter vertical.
This antenna was first published in QST in the mid-1970's and is
documented in several places, including The Short Vertical Antenna and Ground Radial, Sevick, CQ Communications, Inc.,2003.
I don't mean to diminish anyone else's publications. What makes Dr. Sevick's publications special
and why I respect Dr. Sevick's
work is this. He doesn't take anyone's word for it. He builds it himself and he measures the results himself.
And then he documents the results and publishes them. That's a tall order. Dr. Sevick's career was
at Bell Labs where that kind of "prove it to me" mentality is typical.
Next, I will discuss how I constructed my vertical and how I made my measurements.