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Part 15 Night Time Requirements
- Thread starter H82BL8
- Start date
H82BL8 said:
I think the answer is yes to all of those.
You must first grasp the concept that Part 15 is not really about hobby broadcasting. Part 15 is to clarify which electronic devices are intentional or unintentional radiators. Garage door openers and our little transmitters are intentional radiators, that is they were designed to transmit a signal. Televisions, computers, power supplies, ect are unintentional radiators in that they have electronic circuits that do spew out some RF crap about the spectrum even though they are not meant to. Part 15 breaks down the spectrum into little segments and tells us how much signal each of these devices are allowed to emit. In the AM and FM bands it spells out how much power or signal strength is allowed before you have to go out and get yourself a license! LibertyNT is correct in that Part 15 does go into a little more detail about antennas and technical specifications of the transmitters, signals, ect. but is pretty much silent on the content of those signals.
The good news is that an FCC Public Notice issued in 1991states that there are no restrictions on the operating hours and content of a system that meets Part 15 AM / FM Rules.
The bad news is that this notice shows the "Approx. Maximum Coverage Radius" of such stations to be "200 feet."
See http://www.fcc.gov/mb/audio/decdoc/scandoc/910724/1.jpg
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The bad news is that this notice shows the "Approx. Maximum Coverage Radius" of such stations to be "200 feet."
See http://www.fcc.gov/mb/audio/decdoc/scandoc/910724/1.jpg
//
H82BL8 said:
If 1% of the 800 person potential audience is listening to your station would that be considered a success? (with all that's available on radio/satellite/cable/internet/cellular that would be closer to reality) ...It would be better to get venture capital and put a real radio station on the air!
p.s. knowing how seriously degraded the "graveyard" frequencies are (1230/40, 1340, 1400/50/90) at night, the range of your station will probably go from about 4 city blocks in the daytime to just 1 city block at night (on an average receiver - not a DXer's setup), even on the "x-band" (1610-1700) The distant station couldn't care less about your interfering with them, since you're beyond their normal service area, but listeners to your station aren't going to enjoy hearing another station(s) under yours since there are much clearer to hear options available...Sorry, but Part15 AM is really narrowcasting in the truest sense of the word...
H82BL8 said:
For further consideration about usable coverage into a 20-story building -- most such structures use a steel framework and concrete with re-bar for their floors and exterior / interior walls, which all is rather opaque to medium-wave frequencies.
Even the signals of licensed, local, commercial AM broadcast stations radiating a kilowatt or more can be difficult to receive inside such a structure.
Also, the radiation from a typical Part 15 AM antenna is maximum in the horizontal plane, and much less at high vertical angles near the zenith (+90 degrees).
So even if the Part 15 station was located on or near the lowest floor of such a building, it would not radiate much energy toward its upper floors (sorry).
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H82BL8 said:
Have no idea if you're actually living in the building that you're describing, and even if you could permission to get the management to allow you to install an AM carrier current system, my guess is the building's electrical infrastructure would have multiple transformers that one would have to 'bypass' because the signal would be seriously degraded in strength going through a power transformer...the cost would be astronomical for a hobby station.
Perhaps FM would work better, especially if you were on one of the middle floors and could keep the signal confined to the building... Things might be different where you are, but in my area I can only get reliable reception for about a block or so in the daytime (and we're not talking about a commercial grade signal at that distance-- just something that's listenable on a good car radio). At night time, the range extends to about the end of my driveway. Sometimes, I can even hear interference within my own home at a distance of 50 feet or so from the antenna. This is due to co-channel interference from distant stations, and hiss from IBOC transmissions on adjacent and second-adjacent channels. I don't bother with FM because it doesn't even cover the house. That is not surprising, since 50 microvolts is hardly a usable signal in an urban area, and that's what you're allowed at 15M (about 50 feet).
I like the idea someone else suggested of putting up a Wi-Fi network that people could log on to with their computer and receive your audio signal that way. You'd have to put some effort into publicizing it, but I think this could work reasonably well. You could set your SSID to broadcast a message like "OldiesRadio" and it would easily show up in a Wi-Fi scan.
I like the idea someone else suggested of putting up a Wi-Fi network that people could log on to with their computer and receive your audio signal that way. You'd have to put some effort into publicizing it, but I think this could work reasonably well. You could set your SSID to broadcast a message like "OldiesRadio" and it would easily show up in a Wi-Fi scan.
If You Properly Set up a rangemaster you can go 2 miles or so.
I think that Info on the FCC site is outdated. I saw that 200 Foot deal.
But that would mean practically all Part 15 stations are Illegal.
SO im guessing the FCC changed that for AM. as the Part 15 we all use mentions
no field Strength Limit.
I think that Info on the FCC site is outdated. I saw that 200 Foot deal.
But that would mean practically all Part 15 stations are Illegal.
SO im guessing the FCC changed that for AM. as the Part 15 we all use mentions
no field Strength Limit.
I am using a Rangemaster, and it works well (better than anything else I have tried so far), but I do not find that it is realistic to expect 1-2 miles of useful range in an urban environment, given the clutter and noise that is present on the AM band today. I am able to achieve about 1-2 blocks under ideal daytime conditions with a signal quality level that someone with a decent car radio could actually listen to. The signal can be detected at a greater distance, but the quality is such that the average radio listener would not find it useful.
My apologies if this has been posted before, but here is a link from the Ramsey website to an FCC Bulletin on low power, non-licensed transmitters and to Part 15.
http://www.ramseyelectronics.com/resource/default.asp?page=fcc
http://www.ramseyelectronics.com/resource/default.asp?page=fcc
audioguy said:
I have found that 1--2 blocks is the best you can expect of a usable signal.
radioman148 said:
i have found the same, im actually doing more then the 2 blocks though im at about a good 8 to 10 block just gettin alot of humming...with no compression or innovonics 222... im actually waiting on them to come in to see what we can get...
im in a urban city in new jersey.. we currently have 4 rangemasters up and planning to get 4 more....
Radio Systems is about the only company I'm aware of that still makes carrier-current transmitters:
http://www.radiosystems.com
I also have a Rangemaster but am finding that most listeners discover us via the Internet stream instead.
This remains true even locally. I'm on 1610 now with the Rangemaster with maybe 1/2 mile coverage.
WJJD runs 24/7 now. (In our earlier days, and when it was over the air on 1160 as well, I ran as a daytimer
due to nighttime interference. The Cunnigham transmitter got out about 2 1/2 miles.)
http://www.wjjd1160country.com
http://www.radiosystems.com
I also have a Rangemaster but am finding that most listeners discover us via the Internet stream instead.
This remains true even locally. I'm on 1610 now with the Rangemaster with maybe 1/2 mile coverage.
WJJD runs 24/7 now. (In our earlier days, and when it was over the air on 1160 as well, I ran as a daytimer
due to nighttime interference. The Cunnigham transmitter got out about 2 1/2 miles.)
http://www.wjjd1160country.com
RudeBoy said:
How far do you get a usable signal? I can hear my station 6 blocks away on a good car radio, but nobody else is going to listen to it at that distance.
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