Total posts : 45366
The 4-individual wires of the 4-element should not be electrically connected to each other at the top, in my opinion, otherwise you’d be loading the signal back into each wire from each other wire and there could be some phase cancelation. That is entirely an unscientific attitude, like avoiding ground loops being another example where electrical connections should not be made at more than one point.
The tuning, matching, I think, is done as you would to a single wire, element or pipe.
The bottom should be fed from a single point outward like a spider of equal-length wires to the 4-elements, which should be secured to be equidistant from each other all the way from top to bottom.
There are no estimates yet as to how close or far apart the elements need to be from each other.
I wouldn’t recommend a metal electronically attached ring at the bottom, unless the ring was a solid piece of metal, because the RF wire from the transmitter needs to feed the 4-elements from a center point, so perhaps a non conductive pair of rings for securing the top and bottom of the 4-elements would be desirable.
For my FM cage I used securing devices (top and bottom) constructed from toothpicks and corks which I will photograph and post rather than attempt to verbally describe. The FM cage is held in the air from a three-leg tower built from bamboo poles.