I just came across a NMO to N base station converter that i picked found at a pawn shop and i want to mount an 800mhz mobile whip to this for a trunk system in my area. The antenna is a 3 db gain 855 MHz whip 13 inches with a coil towards the bottom and an NMO mount, however the base station converter didn't come with radials..no problem i can make some out of materials i have. My question is how long would i have to make my radials For this 13 inch whip ?