It is well documented that a lengthy ground wire connecting an elevated transmitter to earth exceeds the 3-meter limit imposed by 15.219, and all schemes to circumvent this problem with lightning arresters or toroids have doubtful benefits.
There are two solutions being presented for consideration.
Solution # 1 is to convert the transmitter ground to an infra red beam and shoot it to the earth where an infra red receiver converts the ground to a very low impedance and connects direct to a ground rod and buried radials. A second infra red beam from earth to transmitter would provide the return path for the ground;
Solution # 2 is to do much the same thing but with a fiber optic path from transmitter to earth. Fiber optical cable is a two-way medium and would provide the 2-direction pathway.