Hello, I'm planning to build a biconical antenna, for a center frequency of around 162MHz, and a flare angle of around 30° (both upper and lower cones are identical.

I've read in John D. Kraus' "ANTENNAS" (2nd edition), that the impedance of an infinite biconical antenna is Z_r = 120 * ln( cot(theta/2) ), where theta is the half-flare angle, so in my case around 15°.

What I found confusing, however, is how to calculate the impedance for a finite (i.e. an actual, practical antenna). Since the center frequency shall be around 162MHz, I imagine a quarter wavelength cone length is in order, but the book states this might not be the case. The rest of the book kinda goes over the top of my head when I really just require a formula to calculate the impedance depending on the flare angle and length of the cone. Is there a book or somewhere where I might find that?

Furthermore, the book doesn't really go into detail how the flare angle influences bandwidth. In its extreme form, (flare angle 0°) the antenna is basically just a regular half-wave dipole, but the larger the flare angle, the wider the band of the antenna. How exactly the angle relates to the band widening, is not explained.

And last but not least, How do I connect my Antenna to a 50 Ohm RG8 coax cable, when the impedances don't match. According to my (rather mediocre) calculations, the impedance of the antenna is much higher than 50 Ohm, roughly about 100 Ohms, How do I match them up properly? I imagine I need some sort of balun if I want to attach the lower cone to the shield of the coax and the upper cone to the core?