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#1
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![]() wrote in message ups.com... My question is this: so long as final output to the antenna is within the requirement of part 15 unlicensed operation, is part 15 unlicensed operation allowed within a band normally governed under part 97? Part 15 operation would easily cover a 30 mile radius on 80M. http://www.access.gpo.gov/nara/cfr/w...7cfr15_06.html Part 15.223 says in part... "Subpart C_Intentional Radiators Sec. 15.223 Operation in the band 1.705-10 MHz. (a) The field strength of any emission within the band 1.705-10.0 MHz shall not exceed 100 microvolts/meter at a distance of 30 meters. However, if the bandwidth of the emission is less than 10% of the center frequency, the field strength shall not exceed 15 microvolts/meter or (the bandwidth of the device in kHz) divided by (the center frequency of the device in MHz) microvolts/meter at a distance of 30 meters, whichever is the higher level." For CW operation, your bandwidth is zero for all practical purposes. You will therefore be allowed 15 uV/m at 30 meters. From this I made a very crude estimate of your allowed transmitter output power. Assuming your transmitter antenna is 100% efficient and radiates hemispherically, your transmitter output power is allowed to be no more than about 1.7 nanowatts (1.7e-9 watts). For ideal circumstances (0 dB receiver antenna gain, 100% efficient receiver antenna), you would get less than 5 uV at a receiver 400 meters away. I stress that this is for ideal circumstances. If your transmitting antenna is less efficient, you can run more power, but less of your power gets launched. How efficient is that antenna, anyway? On the other hand, your antenna may have some directivity which would further limit your power. This is making my head hurt. All that can really be said about this estimate is that, to be safe, you should not have much more than about 2 nanowatts output power unless you have the ability to measure the field strength according to regulations. Good luck with your project. 73, John |
#2
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John,
So, say I had a CW oscillator on the colorburst frequency. I'll shunt the output with a 50 ohm resistor to ground. I'll put a random wire at the top of the resistor. Basic equations yield P = (EE) / R If R is 50 Ohms and maximum output power is 1.7e-9 watts, then E is 4.1e-5 volts. So, would a measurement of 40 microvolts or less across the resistor be satisfactory? Thanks, The Eternal Squire On Jan 25, 9:44 pm, "John" wrote: wrote in oglegroups.com... My question is this: so long as final output to the antenna is within the requirement of part 15 unlicensed operation, is part 15 unlicensed operation allowed within a band normally governed under part 97? Part 15 operation would easily cover a 30 mile radius on 80M. http://www.access.gpo.gov/nara/cfr/w...7cfr15_06.html Part 15.223 says in part... "Subpart C_Intentional Radiators Sec. 15.223 Operation in the band 1.705-10 MHz. (a) The field strength of any emission within the band 1.705-10.0 MHz shall not exceed 100 microvolts/meter at a distance of 30 meters. However, if the bandwidth of the emission is less than 10% of the center frequency, the field strength shall not exceed 15 microvolts/meter or (the bandwidth of the device in kHz) divided by (the center frequency of the device in MHz) microvolts/meter at a distance of 30 meters, whichever is the higher level." For CW operation, your bandwidth is zero for all practical purposes. You will therefore be allowed 15 uV/m at 30 meters. From this I made a very crude estimate of your allowed transmitter output power. Assuming your transmitter antenna is 100% efficient and radiates hemispherically, your transmitter output power is allowed to be no more than about 1.7 nanowatts (1.7e-9 watts). For ideal circumstances (0 dB receiver antenna gain, 100% efficient receiver antenna), you would get less than 5 uV at a receiver 400 meters away. I stress that this is for ideal circumstances. If your transmitting antenna is less efficient, you can run more power, but less of your power gets launched. How efficient is that antenna, anyway? On the other hand, your antenna may have some directivity which would further limit your power. This is making my head hurt. All that can really be said about this estimate is that, to be safe, you should not have much more than about 2 nanowatts output power unless you have the ability to measure the field strength according to regulations. Good luck with your project. 73, John |
#3
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#4
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John Smith I wrote:
But .0000000017 watts? I thought we were talking a full watt! (more of a pirate in me than some grin) JS |
#5
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John Smith I wrote:
Anyway, I would pursue this much differently. Indian reservations are exempt from MANY of the rules, regulations and laws the rest of us non-indigenous peoples are subject too. I'd see if the above were not a factor in all this. JS |
#6
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John Smith I wrote:
John Smith I wrote: Anyway, I would pursue this much differently. Indian reservations are exempt from MANY of the rules, regulations and laws the rest of us non-indigenous peoples are subject too. I'd see if the above were not a factor in all this. JS Just think! Instead of the Indians having a monopoly on all gambling in California (yes, I know, it is really vegas using the Indians), they could now go ahead and get a monopoly on all broadcasting! JS |
#7
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John Smith I wrote:
John Smith I wrote: John Smith I wrote: Anyway, I would pursue this much differently. Indian reservations are exempt from MANY of the rules, regulations and laws the rest of us non-indigenous peoples are subject too. I'd see if the above were not a factor in all this. JS Just think! Instead of the Indians having a monopoly on all gambling in California (yes, I know, it is really vegas using the Indians), they could now go ahead and get a monopoly on all broadcasting! JS Myself and a colleague discussed the number of permits and variances needed to launch real, orbital-type rockets and wondered how much would be required if you launched from a Native reservation. |
#8
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![]() wrote in message oups.com... John, So, say I had a CW oscillator on the colorburst frequency. I'll shunt the output with a 50 ohm resistor to ground. I'll put a random wire at the top of the resistor. Basic equations yield P = (EE) / R If R is 50 Ohms and maximum output power is 1.7e-9 watts, then E is 4.1e-5 volts. So, would a measurement of 40 microvolts or less across the resistor be satisfactory? Thanks, The Eternal Squire I think it would be about 300 uV across 50 ohms ( I think you are off by about an order of magnitude). Yes, I think that would be okay. A good place to understand this stuff is on the ARRL site. Look into the BPL and RFI things there. Read everything you can find about this subject. If you research this thoroughly, you will find allies in the field, I'm sure. My intent here is not to discourage you in your project, but to encourage you to think critically. Always ask yourself why this has not been done before. Most of the time there is a reason, but sometimes (a small percentage of the time) it is because nobody has had an interest in the subject. But, you didn't ask for my philosophy. I sometimes get carried away. I apologize for that. Cheers and 73, John |
#9
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If (mind you, IF) I was going to make a device that would bootleg a signal
over a 30 mile range, the LAST frequency I would pick is one that had a real good chance of messing up somebody's color TV set in that radius. Google on Mouser, crystal, and you will get HUNDREDS of cheap crystals that aren't going to be messing up anybody's home entertainment devices. You might also google for "emergency frequency" to keep away from the Coast Guard's "hit the red button" frequencies. If it twer me, I'd probably find a quiet spot on 80 meters for the little rugrats. Jim wrote in message oups.com... John, So, say I had a CW oscillator on the colorburst frequency. |
#10
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Okay, suppose I make a colorburst CW oscillator and shunt it with a 50
ohm resistor. I'd put a random wire at the top of the resistor. So from basic equations P = (EE)/R, with a power limit of 1.7 nanovolt this gives a voltage limit of 0.6 microvolt. I'm afraid I don't have a voltmeter or scope that goes that low. The Eternal Squire On Jan 25, 9:44 pm, "John" wrote: wrote in oglegroups.com... My question is this: so long as final output to the antenna is within the requirement of part 15 unlicensed operation, is part 15 unlicensed operation allowed within a band normally governed under part 97? Part 15 operation would easily cover a 30 mile radius on 80M. http://www.access.gpo.gov/nara/cfr/w...7cfr15_06.html Part 15.223 says in part... "Subpart C_Intentional Radiators Sec. 15.223 Operation in the band 1.705-10 MHz. (a) The field strength of any emission within the band 1.705-10.0 MHz shall not exceed 100 microvolts/meter at a distance of 30 meters. However, if the bandwidth of the emission is less than 10% of the center frequency, the field strength shall not exceed 15 microvolts/meter or (the bandwidth of the device in kHz) divided by (the center frequency of the device in MHz) microvolts/meter at a distance of 30 meters, whichever is the higher level." For CW operation, your bandwidth is zero for all practical purposes. You will therefore be allowed 15 uV/m at 30 meters. From this I made a very crude estimate of your allowed transmitter output power. Assuming your transmitter antenna is 100% efficient and radiates hemispherically, your transmitter output power is allowed to be no more than about 1.7 nanowatts (1.7e-9 watts). For ideal circumstances (0 dB receiver antenna gain, 100% efficient receiver antenna), you would get less than 5 uV at a receiver 400 meters away. I stress that this is for ideal circumstances. If your transmitting antenna is less efficient, you can run more power, but less of your power gets launched. How efficient is that antenna, anyway? On the other hand, your antenna may have some directivity which would further limit your power. This is making my head hurt. All that can really be said about this estimate is that, to be safe, you should not have much more than about 2 nanowatts output power unless you have the ability to measure the field strength according to regulations. Good luck with your project. 73, John |
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