I DO NOT want nor intend to start the ground lead discussion (again)
However, I KNEW I had this laying around someplace.
Back when I was first shopping for a trasmitter and carefully scrutinizing all the websites of various makers, I saved and printed most of the info I found for later extensive analasys.
At the time, not knowing diddly about the long ground lead issue. Procaster had this as their opening page on their website:
Clearly showing what is an illegal in the USA ground lead. Now, I know things are different in Canada and it's probably fine up there. But as a Part 15 newbie back then I would have installed my transmitter exactly like this (it's also covered in the installation manual). I would imagine that thousands of innocent newbies who just searched, found, bought, installed, without researching and reading a bunch of forums would have never suspected possible trouble.
In face my installation looks exactly like the one pictured, except my transmitter is outside mounted to a wooden outside attic window frame, and I don't have any ground lead at all.
I see they've changed their website since then, nearly 2 1/5 years ago.
TIB
Here the rule is the same as the US for AM and antenna and ground.
But BETS-1 for AM is field strength and not about power or antenna length.
BETS-1 says 250uV/M@30 meters.
So the set up in your posted picture would not be illegal here under BETS-1.
This is truly a legend as told to me by several radio people over the past several years.
Once upon a time the FCC was lax about counting long ground leads as part of the antenna length under 15.219. So the story goes.
The tale continues. Aware that long ground leads would make Part 15 AM transmitters more appealing to the marketplace, manufacturers made "long ground leads" part of their instruction for safe installation.
One radio engineer somewhere in the U.S. spotted the long ground lead as a possible source of "bonus" radiation and, remembereing this is only an anecdote handed down from the past, this engineer turned "ground lead justice" into his own life mission, and began warning manufacturers they were in violation of FCC rules. The manufacturers were highly annoyed by this engineer's ongoing assault.
What's more, this is what I was told, that self-deputized engineer began phoning, mailing and e-mailing the FCC complaining vigorously and persistently about the detected violation. Although feeling pestered by the constant complaints, FCC Inspectors responded with action.
Crack-downs began, transmitter users were notified of violations, manufacturers were forced to edit their instructions removing the ground lead part.
Transmitter sales hit the dumps.
Today this fabled engineer rides his victory as if it were the invention of radio itself. This isn't me making this up, it's only based on stories. As we hear it, he holds top place as the "discoverer" of radiation from long ground leads. It is a subject that attracts him like a bear to a dead fish.
I'd like to know what the field strength would have been for an antenna mounted in that way. And if it met the field strength rule how far did it go? Maybe someone would actually test that installation and find out.
Do a search on this site. Rich has published field strength graphs several times for both strictly legal Part 15 AM transmitters, and those with long ground leads.
As for Canada, there is BETS-1 (for broadcasting to the general public) and RSS210 (for everything else). RSS210 is essentially the same as Part 15 (sans broadcasting) and that ProCaster installation cited by Tim would be illegal there as well.
In the real world, however, I have never seen anyone running under RSS210 in Canada told to cease and desist because their ground lead was too long. And that is after extensive research. It IS possible that it has happened and never been communicated publicly.
I have also never seen anyone broadcasting (as opposed to non broadcasting) using RSS210 (i.e. Part 15) certified transmitters on the AM band get shut down either.
I've tried to understand some of those graphs and have a hard time with it. Maybe its my vision I am not sue. I'll have to try and find out about how far a system installed like that of what was posted on the website years ago would go. Yup one person always has to spoil everyone elses's fun. Never ends. Anyways nice link.
I also would prefer not to see this thread drag on and on on the ground lead topic so perhaps we should post experiences and leave all the other much discussed stuff out.
I will just add that my experience with a ground mounted over radials AM transmitter, legal according to 15.219, gives a decent signal out to about a mile on a car radio. I have no experience with tx. using long ground leads for comparison.
Neil
The thing to take away from those graphs is the field strength - the transmitter with a long ground lead has a significantly higher field strength than that of one ground mounted and that strictly complies with Part 15 regulations. I seem to remember it was about double, but not sure about that.
I just realized it would be VERY easy for me to test.
Well, maybe not VERY easy.
My transmitter is on the third floor attic window. It's not connected to any ground. It would be VERY easy to clip a ground wire to the lug and clip the other end to my ham radio antenna ground which is a big ol' ground wire that goes down into the Earth and comes out in my basement and is connected to the water pipe where it comes through the floor into the house. It's a VERY good ground. Here in old small town USA it goes right out to the street system and it's all metal.
It wouldn't be too tough to take a FS reading at one of my fringe spots, connect the ground, take another reading, and compare the difference.
Of course to do this I have to remove the attic window to access the transmitter.
But it sure is tempting.
I've often wondered what would happen if I moved my transmitter to the ground and ran the ground lead straight down into the Earth where it would enter my basement and connect to the water pipe. If that would be better than my elevated install with no ground? I never worried about it because when I put the transmitter up I got the minimum range I needed and didn't experiment.
How good is our water system ground here? Let me tell you. In the winter, when we get a week or 10 days of temperatures around -25 or -30 below the water pipes buried in the yard, and even out in the street often freeze up. You're supposed to remember to leave your water running when it's this cold so it won't freeze, but people forget. Anyway. The cure for this problem is... you call "the guy". "The Guy" comes in a big truck with a huge Lincoln welder in the back. He connects one long thick cable to your water pipe in the basement, and the other end to a water shut off valve out in a front yard, or in a sidewalk, or in the street, and puts the juice to it. It heats up the pipes and melts the ice in the pipes! I've seen him do it on our block where due to 12 foot snowbanks and ice, he has to choose a shutoff valve nearly a block away, and he still gets continuity from there to a house! It's pretty amusing if you've never seen it done before.
Ugh. Do I have the ambition to make the test. Now I'm So curious.
TIB
My AMT3000 is connected to a firm ground down in the basement which is attached to water pipe and electric box earth ground, and the signal is very intense within 200-feet, but drops off fast.
The AMT5000 has two radials in the ground, one running south and the other north. The range is blocks and blocks and blocks, sometimes a mile other times not.
The point is, there is a significant difference between an electrical ground and radials.
Mr Blare wrote in Reply 3 above: ... This isn't me making this up, it's only based on stories. ...
The clip quoted above is by far the most truthful and significant content of that entire post.
The topic of radiation from long "ground leads" will disappear from these boards when its existence and value in producing higher radiated fields than possible for compliant FCC §15.219 systems is understood -- rather than denied and subverted.
My comments above are made at the request of a radio engineer somewhere in the U.S.