The entire northeastern US is notorious for poor am reception caused by horrible ground conductivity and man-made noise. The Northeast where a 50kW AM can squeak out 50 miles... (VS the midwest where 5kW can cover 100+ miles easy)
Ditto on gas station interference, oddly in town at the only gas station my part 15 has no problems yet in the next town over the pumps wipe out AM and much of FM. At the in-town gas station I suspect if there was no overhead canopy there would be no signal fade at all.
I'm sure the ground conductivity is not as good as the USA as much of Canada is on the Canadian Shield which is higher elevation and as I understand lower lying flat land is more moist and conductive. Maybe southwestern Ontario would be best for ground conductivity. Also southern BC and Vancouver Island. The map of ground conductivity doesn't include the Canada map. But you have to be fortunate to live with your own property on the right type of ground for this to even matter.
Mark
Maybe it explains some of my frustration with AM that some other people are not experiencing and that they can't understand why I'm so frustrated. If the ground conductivity is so bad and there's more man-made noise from the Northeast and even maybe the southeast who knows. I would think that North Carolina and Virginia are somewhat in the middle Southeast section. still close to the Seaboard.
In post #15 I called to question a statement made by another poster because it read as a statement of universal truth. Such statements can be discouraging to those seeking advice or help with Part 15 activities.
I do not question the validity of anyone's reports of their personal experience but I do point out that extending a personal experience to a general conclusion is not valid.
Just in this thread alone there are reports of success with AM as well as problems with AM. Both types of experiences are valuable learning information, especially those reporting good results with AM since these show that it is possible.
Neil
I know New England is real bad, as well as a HUGE chunk of the eastern seaboard thanks to the rocky soil. Charlotte, NC apparantly has AWFUL ground looking at the pattern for 50kW WBT. Compare that to 5kW KLIF, 5kW WNAX, or 50kW KFAB.
The difference a good ground can make to Part 15 AM is amazing, and in my experience is a much greater factor than background noise.
Case in point. When I lived on Bowen island (basically a big rock sticking out of the ocean), the ground mounted Rangemaster I had barely went 1/4 mile to a good car radio, and that was with radials.
When I lived in Pitt Meadows (situated on the floodplain of the Fraser River), with a ground mounted Rangemaster (the same one), grounded to just a single metal pipe driven into the earth, I got over 1 mile, and almost double that in some directions, with the same car radio.
Bowen Island is semi-rural, and in the area I lived, it was all relativey small houses on very large lots (acreage) so all in all little noise.
In Pitt Meadows, I was in a suburban area, mostly smaller homes on small lots, but a lot more of them, so a lot more noise relatively speaking. And still the range was much greater in Pitt Meadows.
I just read a report. Field Measurements Of Unauthorized FM Band Radio Signals In New York, N.Y.. This bothers me. I am SO glad I did not fire up the 30 Watt Veronica, dialed back to 1 Watt! I now have my Signstek down to setting 2.
Even AM is out of the picture. Forget that Greek 10 Watt unit! LOL! Read this entire 103 page report. It's a PDF:
https://dl.dropboxusercontent.com/u/82565753/Pirate%202016%20study%20final%20pdf.pdf
Thoughts? I had no idea about any of this. Miami is just as bad...
Doug
Makes sense, NYC has a huge pirate problem. I'm curious if other high pirate areas have the same thing. In Dallas we mostly rely on interference complaints.
I got a link to the New York law on piracy from let's say a free radio site. It was interesting to know as other forum members of that site suggested that the local police in New York had no jurisdiction on anything below 88.1 megahertz as the article to suggest.
If need be I can go to that site get the link and post it here. The funny thing was that our favorite hobby broadcaster person had posted a comment on the engineering site but didn't even mention that anything below 88.1 was out of New York's jurisdiction.
How I found this was I've been Googling for 87.7 megahertz and 87.9 megahertz and free space trying to find out if there has been any recent updates to the possibility that we may be able to soon legally broadcast on the lower portion of the FM band. As it is right now from what I gather it's not yet legal however there was a link to a new certified Wi-Fi transmitter That was supposed to transmit down in that white space area.
what I want to know is if that is the case is it limited to internet Transmissions only in the white space area or will we soon start to see certified audio transmitters in that area which is supposed to scan for a blank frequency. If its user controlled in any way shape or form trying to make it transmit on 87.7 or 87.9 and then let the transmitter check to see if it's okay I might be the way to do it. I will continue to Google and do research to see if any new developments arise from this. I just thought I would let you know what I have found and like I said I will post the link if need be of the particular article I'm talking about.
Thoughts ...yes. It's all about interference being the problem. Then why is all the interference that prevents an AM station from getting a good signal to listeners in a given area, especially in their homes allowed? What about that? How come you don't hear of an AM station complaining about this and going after the FCC to stop it?
And why are the HD stations right where the normal stations are, wouldn't common sense say to expand the FM band to say 80 to 108 and all the HD stations can go there? You could fit hundreds in a small space as transmitting via binary code takes a lot less space unlike analog.
Mark
Putting HD on a separate frequency then analog FM would be the wiser idea I totally agree. However for some reason the FCC has done the public Wrong by not doing so.
Something more Sinister is going on here other than worrying about interference. There are some things in that hundred page report that I totally disagree with. One thing that stands right out like a sore thumb is the fact that most of these stations were running well over 100 watts and yet the safety for health is at 20-foot so half of 100 watts is 50 which would have been 10 foot 25 watts at 5 foot and 12.5 watts at a lesser range to be safe. this suggests that anything under 10 this suggests that anything under 10 watts is really not that much of an issue.
in the In the report 10 watts was also mentioned for interference nothing underneath 10 watts was even mentioned in that survey and report. This also points the fact that one what would not be a problem in fact even greater wouldn't be a problem keeping it under 10 watts.
I've spoken I've spoken on this subject in more detail on the new radio Revolution site so I'm not going to go into that over here. Getting back to the subject of a.m. and I'll be ready oh I understand that part 15 was meant to stop interference. But if a separate service was made for had the radio on AM without the without the silly ground rule of three meters I think we could actually have usable range That most people could be happy with.
many have said many have said that with a better antenna ground system even at 100 milliwatts you could do 5 miles easily. But again that might not work for apartment dwellers. Right now there isn't a project being worked on that could help that situation a little bit. Will see as time marches on.
Back on topic, I find the Pirate/interference problem heavy in big cities. A town like Legacy lives in, a ten watt FM is perfect. A nice neat little package to cover most of his town. But a good ten watt is expensive! So you find these Chinese corned beef hashers for $50. A recipe for a NOUO.
But, Legacy, the one you have is a good one from what I've researched. Your issue is modulation, and I see you have that covered. But FM is best for multi-unit apartments. Mine is a four-plex. My Signstek tx covers the whole building on 10mw. That's setting 2.
I wonder how this would do in a 10-story apartment/dorm? I'd check it on full power (1/5th of a watt) and see if it covered everyone. The problem you get when you crank the power on any FM transmitter is, nearby radios get saturated. Your next door neighbor might not pick up their favorite local station, recieving YOU instead.
That could be problematic. Complaints come from that sort of thing. "I can't listen to Z-93 any more! Some new station is playing polka!" LOL! Whatever. It happens. Imagine firing up the Veronica with a full 30 watts in the middle of an apartment building! With a Comet Co-linear in the middle of the room! Haaa haha! Don't.
I seem to be in a very fortunate situation here. My building is getting a clean FM stereo signal, and I'm not breaking the law! I don't think. But...that does not solve the issue where Part 15 FM cannot be used for real broadcasting like AM can. Legally.
Interference on FM is a BIG problem. My concern is the "proximity effect" on nearby radios at powers above the rules. A 5 watt can blanket a neighbors radios and cause complaints. You might not even know about it. Just that you get visited. That's never good.
Harmful RF radiation? I'm not even gonna go there. I don't know enough about it. Legacy's formula above makes sense to me.
Doug
First off if you live in a fourplex I would keep my signal down to about 500 milliwatts that's if you know they listen to other stations. I myself visit my neighbors and ask them directly along with carrying my radio around the complex and to the other complexes nearby to see what type of interference I might be causing.
They Know if they hear me to call me or knock on my door. If bleed becomes an issue I'll go AM with a Spitfire or other AM TX and again check. I'm always concerned about RF interference and if the EDM could cover 1 1/4 mile to a car Radio I'd like that as Tim said No Spurs on his spectrum analyzer.
Even my Whole House 3.0 310 mW TX washed out FM where as the 7 Watt did not.
I'm not here to tick people off here but this was a good point and something to learn from.
FCC §15.239 applies to the fields existing 3 meters from the antenna radiating those fields, regardless of the physical location of that transmit antenna inside or outside a structure, and/or the configuration of that structure.
The FCC limit of 250 µV/m at a distance of 3 meters from the transmit antenna applies no matter the power output of the transmitter, the maximum gain of the transmit antenna it uses, and the physical location of that system (inside or outside).
I have tried to bite my tongue and remain silent regarding some of the ridiculous technical "facts" which have appeared in this thread but, alas, I have failed.
TheLegacy, in particular, throws out power levels and offers advice for legality and safety which has no factual basis and it is time to return to the truth which is the legality of a Part 15 FM transmitter and antenna system is determined by the maximum field strength which is produced at a specified distance.
Trying to correlate power and antennas to legailty is just plain wrong. It is time to stop misleading people that a certain power is OK or that not producing interference to neighobors' reception makes it legal for it certainly does not.
TheLegacy wrote "I am not here to tick people off.." which is admirable but fails with me.
Neil