[TowerTalk] More on radials

[Jim Brown]

On 9/5/2017 5:11 PM, Rudy Bakalov via TowerTalk wrote:
> Now that I have decided to lay on the ground radials,

How many do you plan to install?  You'll need a lot more on the ground 
than elevated to achieve the same low ground loss.  4 per vertical is 
minimum for elevated radials, and I wouldn't consider anything less than 
32 on-ground radials. Elevated radials need to be close to a quarter 
wave, but on-ground radials are lengthened by their proximity to the 
earth, so have VF on the order of 0.8. In other words, they can be 20% 
shorter.

>   another practical question pops up and so far I have not found an answer.
>
> I plan on shunt feeding for 160 the tower in the center of my 80 4SQ,

How tall is the tower?  Depending on its height, it might be worth 
rigging a sloping wire from the top and feeding it from the base against 
radials. I'd try an NEC model. I'm doing that and getting a couple of dB 
from the tower acting as a passive reflector. (And it needs radials too!)

> can I/should I tie all the radials together? The 160 radials will certainly cover the same distance as the 80 radials so is there a requirement for each 80 element to have its own radials?

I don't know enough to offer advice on this.

73, Jim K9YC