Total posts : 45366
Rich is correct regarding the prevailing science and practice for ground systems in shortwave and AM broadcasting. However, if you were to have such an enhanced ground system inspected by the FCC at your Part 15 AM radio station, you should be prepared to supply the technical reasons for operating such a system under Part 15. Simply put, when you get behind the wheel and drive a hundred mph; and then you are stopped by the police, one of the first questions you will be asked, “Did you know you were speeding?” What would your answer be?
Don’t over build a Part 15 station. Several postings on this site address the Part 15 issues involved with “legal” ground systems. Unfortunately the explanation you have received so far, has either been either cryptic or overly technical. Keith Hamilton and several others, including William Walker, who have been at this game for years, will tell you to elevate the transmitter/antenna package 20-30 feet in the clear. Install a single ground path (conductor/wire) straight to a ground rod. This system has passed and will pass inspection because the FCC considers this ground system a safety or AC/DC fault ground. This ground system, realistically however, will not act solely as a “safety” ground. Because of the remainder of the transmitting system (antenna/support/feed system and ground) will radiate there by extending range some.
If you are really curious, let me give you some internet resources who will be glad to answer phone calls and discuss “real world” practices.
And finally, if you really want the answer to your question, call the nearest District Office of the FCC and ask. They are the folks who will ultimately decide whether you are operating legally or not.