Just a technical aside. Radials installed perpendicular to your antenna and opposite of each other, regardless of whether they are elevated or not, do not radiate. .... .. If those elevated radials are not equal in length and opposite to each other (say, 4 radials, 90 degrees in separation, and all 3 meters in length), then they definitely will radiate. As will sloping radials....
That's interesting, I didn't really realize that although it's probably been pointed out before, but I was really referring to buried radials, I can see how elevated radials might raise eyebrows even if they are of equal length and opposite each other.. But what is clear that the three meter limit specifically and exclusively related to "all radiating elements", therefore use of non-radiating radials buried in the ground are not counted as part of the 3 meter limit. This has been confirmed as an undisputed fact numerous times by various reputable knowledge engineers and I've never seen anyone refute that point - which is what I base my "knowledge" on concerning the matter. I don't pretend to posses any personal expertise on the matter, I say these things based on what genuine engineering experts have concluded.
Just wondering about the FCC response NightAire got from the FCC? It ..... ..Somehow you have to question that. ... ..The wording is antenna and ground LEAD, which seems to not include what is underground. ...
The electrical ground in a typical home is a copper and steel stake 8 to 10 feet in the ground. Does that mean you can't power it from a wall socket because you are using the building electrical ground/wiring, and that will make it work better?
.... When you try to contact them(FCC and ISED/CRTC Canada), you get things like this that they are trying to tell you that the written rule doesn't. "Oh you can't do that and that"....
Yes, exactly, the "ground lead" is self descriptive, it is the path from the transmitter leading to ground, period. It does not include the length of your 6ft or 8ft or 10ft or whatever length ground rod, likewise it does it apply to any radials in the ground either, because none of them are radiating elements.
As for utilizing the buildings electrical ground/wiring for your transmitter - well that's exactly how the Talking House and other similar certified transmitters have always grounded their transmitters, that method is actually part of their certification, even though technically that method does appear to exceed the 3 meter rule (which has always been peculiar yet somehow legal method). Whip and Mast style transmitters on the other hand usually utilize a direct ground lead to ground rod method, which is actually a less controversial method because it does not violate the 3 meter rule (provided it's a ground mounted install) - So go figure.
When you try to contact them(FCC and ISED/CRTC Canada), you get things like this that they are trying to tell you that the written rule doesn't. "Oh you can't do that and that"....
Case in point is that 1991 FCC Public Notice that had been issued in response to a large influx of citizens contacting the FCC with inquiries about starting Part 15 AM community radio stations (this had been instigated from all the media articles and tv news reporting on the Talking House Reality and Billboard Radio craze during the 1980s). Some flustered employee of the FCCs Media Department clumsily threw together that document stating the 200ft range limitations which even the Chief Engineer of the FCC Technical Rules Branch refuted.
https://docs.fcc.gov/public/attachments/DOC-297510A1.pdf (You can tell just by looking at it that it had been hastily thrown together) - It wasn't untill later that when the FCC Chief Engineer was pressed on the legitimacy of that document that he responded that the document "is wrought full of errors" and that the author of that public notice should have consulted with someone from the FCC engineer staff before publishing it.
It exactly the same situation as with the response NiteAir received from the EOT branch, it's just how that particular employee of the EOT interprets what the rules means, but it starkly clear that individual doesn't know and simply replied to the best of his knowledge - with what turned out to be a clearly inaccurate response, just like the FCC Media Branch did in that "still in effect" 1991 Public Notice.
@richpowers Looks like I'm "15" on the FCC's map, although I'm not sure exactly what that means...
@mark It's insane, to me, that you can't get an honest answer from the organization that's supposedly working FOR you (using your tax dollars, anyway). Time for me to stop asking questions...
Oh how most part 15 AM hobbyist would kill to be in a ground conductivity area of 15!! Here in my area in Georgia the ground conductivity is more around a 4, right on the coast it's around an 8. In a past installation of mine that was in Ellabell (ground conductivity of about 4) I was able to acheive reception weakly about a mile from my the transmitter (so an approximate 2 mile radius), this was with about a ten foot ground lead with the transmitter on top of my mobile home in a heavily wooded residential area. but I suspect that if my transmitter had actually been mounted about a foot above the ground to be compliant with the three meter rule it still would have achieved about the same.
I tend to believe that ground conductivity of an area is the most important factor in relation to actual range capability and think most would agree. Although you have to take the ground conductivity map with a grain of salt, if your in a 15, then you already have a lot of potential advantage, but you know there's just so many variables - But a ground conductivity of 15 is a pretty damn good initial advantage!
@mark It's insane, to me, that you can't get an honest answer from the organization that's supposedly working FOR you (using your tax dollars, anyway). Time for me to stop asking questions...
Oh I meant to comment on that. I think that individual from OET did give you his honest answer, from his perspective, but it just wasn't an accurate answer. Don't make the mistake of thinking just because they work at the FCC they have knowledge of the intricacies of Part 15. It's like asking a cop about intricacies of some legal matter, they can answer from their perspective but that doesn't mean what they say is accurate l, because they don't actually know the legal system any better than you or anyone does, for accuracy you have to find what's in the books.
I'm now looking at (over time) having the Hurricane inside, running coax out to a 1" copper pipe with a choke to keep the signal from feeding back and making the line part of the radiator.
I'll mount the pole on a non-conducting base with a fiberglass post in the center to fit the pipe over, and run guy wires out to keep the pole steady.
Finally, I'll bury radials (still determining number and length) around the radiator, I believe running them back to the ground on the Hurricane... although I still have to confirm that part.
If the FCC ever looks at it and has a problem, chances are a snip of a wire will eliminate the issue.
(Starting out it'll just be the Hurricane on the floor with the included antenna stretched to the ceiling and a ground run outside... but at least that will get me started!)
I should have the cash to buy it in a week. Then we'll see how long it takes to come from the UK.
Thanks, everyone, for your insight on all of this!! It feels good to be part of this community.
You might want explore how Dave Richards did it (he still participates here from time to time) This was a long time ago when he was still using a SSTran which is similar to the Hurricane without all the extra bells and whistles. Any he built his own antenna and put the transmitter in a weather proof container to make it a whip and mast outdoor install. https://aa7ee.wordpress.com/2010/10/08/the-sstran-amt3000-a-part-15-am-transmitter/
I'd prefer to have the transmitter outside, but I'm in Oklahoma where we get up above 110F some summers, and down to 0F some winters... and while New Orleans has higher humidity, we must be running a close second. I'm not sure how I'd (cost effectively) keep it from melting, or rusting, TBH.
Still, I would be interested to hear more about what he did.
The 'audiophiles' of the antenna world will say that each radial should have a length slightly longer than 1/4 wavelength.
But in the real world, there's not much point in having radials any longer than the length of your radiator, i.e., about 3 meters, or 10 feet. After that, it's greatly diminishing returns.
The point is to get as many of them down as possible, at least 4, ideally 8 to 16, to improve that effective ground conductivity, and therefore improve antenna efficiency.
I've also seen some radio amateurs put down thin sheets of metal or flashing around the antenna, giving you almost an ideal, fully conductive ground.
Having just gone back and read the preceding posts, you have great ground conductivity, so you can probably get away with 4 to 8 radials.
Height matters more with FM than with AM. When I was experimenting with AM, and located on a flood plain, my ground mounted installation got as much range as when I elevated it. That was in the open, well away from the house. And using a Rangemaster.
When I had a Talking Sign (the Canadian version of the Talking House), I ran the wire outside of the house, and saw tremendous improvement in the range when I managed to get the wire over the roofline (I had to mount the transmitter on the ceiling!). AM signals should bypass obstructions in theory, but if you're installing close to an obstruction (i.e., in your house), I think that wiring and the materials in the house will absorb part of the signal. That's why it was important to get the wire (or, in your case, the copper pipe) well above the roofline. My explanation, anyway.
It's good to know the theory. But it's even more important to experiment with Part 15. You never know what might happen!
@nightaire Yo can click that link right above that picture to go to the page where he talks about it, there's also several old post and plans on how many had constructed such antennas for the SSTran because it was such a popular transmitter when they were around.
I never understood why you couldn't simply replace the wire antenna with a whip antenna, which would be a whole simpler - but the reasoning is over my head, evidently doing it that way isn't particularly effective. I don't much about it.
@artisan-radio I've also heard of burying chicken wire or those heavy metal screen door protector panels, I've never tried anything like that myself but anything is usually better than nothing.
Anyway.. it's probably time to start a new thread about this discussion instead of continuing in this old thread about how the Range Extender got its certification!
if you're installing close to an obstruction (i.e., in your house), I think that wiring and the materials in the house will absorb part of the signal.
That's what I've been reading about. My goal is to put it approximately in the middle of my back yard, which puts me about 15 ft or more from our house, the metal shed, and the chain link fence. My wife's not excited about it, but I've promised to make it some sort of a "decorative feature," lol.
I can bury the radials so they're easy to mow over; same with the coax out from the transmitter. The guy wires are a bit of concern; I may need to have decorative rocks or something from the base of the copper pipe out to the guy wire anchors.
For sure this will be a work in progress. I've never done this before, so I won't be surprised if what I end up with only loosely resembles what I'm describing here. 🙂