It's All a Question of Range with Part 15 AM

This is a copy of one of my own responses posted about a year ago in a Hobby Broadcaster thread of the same title. I thought it worthy of reposting here, with some image illustrations added:



The FCC Certified
Hamilton Rangemaster
FCC ID: NXWAM1000

Excerpted from the HobbyBroadcaster discussion;
"It's All a Question of Range with Part 15 AM"  [https://www.hobbybroadcaster.net/community/index.php?topic=7248] :

An example install.

I had a Rangemaster install several years ago, elevated about twelve foot with a single ground rod in an area with a ground conductivity of 4, in a relatively quiet area (no businesses neons, few power transformers or other factors which often lend to increased interference, in a rural area) and I could barely receive my signal at a mile, and that was with the volume full blast and a lot of static, you could barely hear it, - it's not what I would consider a useable signal. But at a half mile it sounded pretty good (so, a mile radius).
I had another similar installation (about 20 foot, single ground rod) but with a ground conductivity of 8, in a congested area, businesses and tall condos and motels surrounding it, etc. and my range fared about the same as described above.

Now, neither employed an engineered ground with radials and so forth, but I assume with a good engineered ground both those previous installs could have achieved a good signal at around a mile (2 mile radius). But note both described involved more than the 3 meter limit, so were not actually to the letter of the law, at the time it didn't really occur to me.. I wish I had tried it at ground level (like the challenge did) and see how the range was affected. 

What I'm getting to is that based on my own experiences, I find it extremely difficult to believe that any legal install could ever possibly achieve greater than a 2 mile radius. But putting my own experiences aside, historically, the range capability of 15.219 has always been documented anywhere from 1/4 mile to approximately a mile maximum radius, dependent on the area.. So is it possible to legally achieve a 2 mile radius with a usable signal??.. With a premium transmitter and a optimal engineered ground in a high conductivity, low interference area?.. Perhaps, maybe, if your really super fortunate. Maybe, just maybe.

At one time was installed on the pinnacle
of the pavilions roof, tied into it's massive
1 inch copper cable grounding system. 

Yeah, about ten or twelve years ago I have had a Rangemaster 40 or 50ft in the air tied into a massive ground system and achieved an easy 10 miles range of usable signal here on the coast, but it certainly wasn't legal.

That's my take on the matter, based on 75% factual and 25% speculative. But I'm no real expert.