At the distances specified (1/2 mile, 1 mile, or whatever) when other qualifiers aren't automatically given, is it...
A. a full-quieting signal (similar in SNR quality to a well-engineered 32-bit audio file) using a crude crystal set with only the internal wiring being used as an antenna
B. using a $250k+ professional receiver that's an AM analog RX only unit specifically built for that one frequency, and a double-wavelength longwire antenna oriented for strongest reception of the station, a signal that's so weak that you'd need a professional RF engineer with $10M+ test equipment AND everything else to be off the air just to even be able to detect the slightest possible hint of a carrier
C. or something in between (please specify)
?? ??
Also, question about 15.221 - campus operation... I share a property line with an elementary school. Could I set up a transmitter at one corner of the property on my property line, make the field strength measurement at the remote corner, and be considered compliant?
Also approximately what power level would be used under 15.209 for the AM band for a portable handheld transmitter using only maybe a 1" antenna, or just internal wiring of the device, to have the maximum legal signal under that rule? And approximately how far would said signal expect to go till it's a weak (but still copyable signal) on a Sangean DT-210 or DT-400W - comparable to say the signal at the purple line on a radio-locator.com coverage map?
And why aren't there any FM transmitters - I'm talking about the ipod car transmitter type, for example, that broadcast the maximum allowed signal under part 15.239? For example, I was with some friends in a minivan sitting in the front bench seat (right behind the copilot seat) and with a reasonable quality FM radio could barely detect the signal from their mini transmitter that was being held by the person in the passenger seat, even though I was less than 5 feet from the transmitter. Sure, it probably doesn't help that this was mostly on I-210 in/near Pasadena and was probably co-channel or adjacent-channel to a local station (but they didn't realize it because they don't listen to FM radio much so don't know what stations are on the air), but considering I have heard my dad's Ramsey FM transmitter in full stereo at distances in excess of 300-400 feet, I expect better from something like that.
Also, assuming direct wave (the way FM works, if it's applicable on this band - not groundwave with its high losses), in operation under 15.225, assuming no co-channel interference (and no skywave being considered unless it's too far for a direct-wave signal to travel), using AM with audio cut off sharply just below 7 kHz and the maximum field strength allowed, how far would that signal expect to be able to go and still have a weak but copyable signal on an average quality radio - one in the $50-150 price range? (I was wondering if it might be practical for some personal use purposes when I might be a short distance from the transmitter site - btw I would be using probably a small handheld transmitter that would have higher ERP than normal to compensate for a very small (1-2") antenna relative to the wavelength.)
Or, what about 15.227 or 15.249?
Also what about 15.217?
And, if I remember correctly, below 9 kHz is unregulated. Seems that there'd be enough bandwidth there for a low-fidelity SSB AM mono broadcast, but does the required antenna size or transmitter power to compensate for an extremely tiny antenna, or the noise level make it so useless that the FCC didn't see the need to regulate it?
Also at the other end, 15.205 says above 38.6GHz is spurious emissions only. What about infrared, visible light, etc? What are the rules for setting up transmitters using those bands? (For example let's say modulating a 100-watt colored light bulb and using it at night - obviously there would be literal line-of-sight limits on coverage though, but would that be legal?)
One more unrelated thing... where's the setting on the forums to change how many posts are displayed per topic page when I'm logged in? Right now it's set at I believe 10 posts per page, but on most forums I have accounts with I set it at an average of 40 or 50 posts per page so I don't have to click next/previous page or applicable links so much.
A. a full-quieting signal (similar in SNR quality to a well-engineered 32-bit audio file) using a crude crystal set with only the internal wiring being used as an antenna
B. using a $250k+ professional receiver that's an AM analog RX only unit specifically built for that one frequency, and a double-wavelength longwire antenna oriented for strongest reception of the station, a signal that's so weak that you'd need a professional RF engineer with $10M+ test equipment AND everything else to be off the air just to even be able to detect the slightest possible hint of a carrier
C. or something in between (please specify)
?? ??
Also, question about 15.221 - campus operation... I share a property line with an elementary school. Could I set up a transmitter at one corner of the property on my property line, make the field strength measurement at the remote corner, and be considered compliant?
Also approximately what power level would be used under 15.209 for the AM band for a portable handheld transmitter using only maybe a 1" antenna, or just internal wiring of the device, to have the maximum legal signal under that rule? And approximately how far would said signal expect to go till it's a weak (but still copyable signal) on a Sangean DT-210 or DT-400W - comparable to say the signal at the purple line on a radio-locator.com coverage map?
And why aren't there any FM transmitters - I'm talking about the ipod car transmitter type, for example, that broadcast the maximum allowed signal under part 15.239? For example, I was with some friends in a minivan sitting in the front bench seat (right behind the copilot seat) and with a reasonable quality FM radio could barely detect the signal from their mini transmitter that was being held by the person in the passenger seat, even though I was less than 5 feet from the transmitter. Sure, it probably doesn't help that this was mostly on I-210 in/near Pasadena and was probably co-channel or adjacent-channel to a local station (but they didn't realize it because they don't listen to FM radio much so don't know what stations are on the air), but considering I have heard my dad's Ramsey FM transmitter in full stereo at distances in excess of 300-400 feet, I expect better from something like that.
Also, assuming direct wave (the way FM works, if it's applicable on this band - not groundwave with its high losses), in operation under 15.225, assuming no co-channel interference (and no skywave being considered unless it's too far for a direct-wave signal to travel), using AM with audio cut off sharply just below 7 kHz and the maximum field strength allowed, how far would that signal expect to be able to go and still have a weak but copyable signal on an average quality radio - one in the $50-150 price range? (I was wondering if it might be practical for some personal use purposes when I might be a short distance from the transmitter site - btw I would be using probably a small handheld transmitter that would have higher ERP than normal to compensate for a very small (1-2") antenna relative to the wavelength.)
Or, what about 15.227 or 15.249?
Also what about 15.217?
And, if I remember correctly, below 9 kHz is unregulated. Seems that there'd be enough bandwidth there for a low-fidelity SSB AM mono broadcast, but does the required antenna size or transmitter power to compensate for an extremely tiny antenna, or the noise level make it so useless that the FCC didn't see the need to regulate it?
Also at the other end, 15.205 says above 38.6GHz is spurious emissions only. What about infrared, visible light, etc? What are the rules for setting up transmitters using those bands? (For example let's say modulating a 100-watt colored light bulb and using it at night - obviously there would be literal line-of-sight limits on coverage though, but would that be legal?)
One more unrelated thing... where's the setting on the forums to change how many posts are displayed per topic page when I'm logged in? Right now it's set at I believe 10 posts per page, but on most forums I have accounts with I set it at an average of 40 or 50 posts per page so I don't have to click next/previous page or applicable links so much.