The CB band is no different than any other band. Height relative to wavelength remains the same.Good low angle radiation can be had with as little as 1/2 wavelength above ground but admittedly even better is a full wavelength. Both heights take advantage of ground reflection gain. Then again two full wavelengths is even better and three is better still etc.
I do have a question, what is the basis for your belief that the best height is 16-17% greater than a full wavelength? I realize that you did say that it was "IMO" so I am wondering what it is in your opinion that this is so and where did you get that figure?
Well CK, back in the early 70's I think my radio mentor gave me a 20 meter wire dipole, and suggested I experiment with cutting and getting it tuned to the middle of the CB band. He wanted to see if I could get it to work good enough to make a CB contact with him about 30 miles southeast of me to his home.
He told me to string it up as horizontal as I could with the ends going east/west more or less, and said that would be close enough to maybe pick him up just a little Southeast of me a few degrees toward Galveston.
I got it to tune and tried to reach him with no luck. I called him and he asked how high was my dipole. I had strung it between two trees, up about 20' feet. He told me, "...this is you first lesson...so don't forget the idea involved unless one day you figure things out better."
He never explained much of anything he was trying to get over to me in words...he wanted me to figure things out with as little instruction as possible.
I climb the trees and got it up as close to 42' feet as possible. I noticed the tune changed on me a bit, and I re-tuned a little, just to get a better SWR.
I made a call to Sanders and on the first call he came back stronger than I could imagined, based on our prior vertical contacts using my old HyGain CLR2.
He told me, "...now figure out what you think just happened in this situation. and tell me about it in a day or two." A few days later I told him what I thought had improved my ability to make the contact, and he never said another word about that wire antenna...even though I asked him questions all the time.
Sanders was a retired Master Sergent in field communications for 25 years, and he did training all over the Pacific area. IMO such guy's typically have just one speed with everything they do, and that is their speed, and you either accept it or get on down the road. He was my friend for 32 years, N4SEX (SK).
Since that those days I've heard and read other folk's suggesting that 42' feet is likely somewhat of a beneficial height at 11 meters and in particular when using a horizontal dipole. But, I've never really understood why for sure.
When I was able to model, I tested that idea with a center fed vertical dipole, and I didn't notice anything out of the ordinary seeming to happen when I reached 42' feet. But I was still curious, and I wanted to see what happened if I went up 6' feet more. Again...nothing remarkable with my vertical model.
Maybe this would be another discussion to see if there is something in theory that considers what the horizontal models below show, and what I was told many years ago by an old man that never had access to tools such as modeling.
Below I modeled a vertical center fed dipole and using the same dipole set horizontal. Low and behold something unexpected seem to happen with the horizontal model at 42' feet...that didn't seem logical considering the explainable responses from the vertical models. I also added a hand written recap of all the models for easy comparisons.
This is the bases of my thinking CK.
View attachment Dipole's at 42' feet.pdf
