Post by bluebucketradio on Apr 11, 2016 12:30:20 GMT
Considered a part of the Medium Wave band and sometimes considered Shortwave, there is a wide slice of frequencies the FCC say are Part 15 approved (i guess)
and they lie above the AM Broadcast Band starting at 1.705 and ending at 10 Mhz. ( 1705 to 10000 )
Rule for this band is 15.223 and I quote it below:
§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 the purposes of this section, bandwidth is determined at the points 6 dB down from the modulated carrier. The emission limits in this paragraph are based on measurement instrumentation employing an average detector. The provisions in §15.35(b) for limiting peak emissions apply.
(b) The field strength of emissions outside of the band 1.705-10.0 MHz shall not exceed the general radiated emission limits in §15.209.
If i am correct in my calculations and i really don't do math well, then we should be allowed about 2 mW in this band however there is another section of rules that some how manages to confuse me.
15.219 Operation in the band 510-1705 kHz.
(a) The total input power to the final radio frequency stage (exclusive of filament or heater power) shall not exceed 100 milliwatts.
(b) The total length of the transmission line, antenna and ground lead (if used) shall not exceed 3 meters.
(c) All emissions below 510 kHz or above 1705 kHz shall be attenuated at least 20 dB below the level of the unmodulated carrier. Determination of compliance with the 20 dB attenuation specification may be based on measurements at the intentional radiator's antenna output terminal unless the intentional radiator uses a permanently attached antenna, in which case compliance shall be demonstrated by measuring the radiated emissions.
The last few lines of 15.219 says " All emissions below 510 kHz or above 1705 kHz shall be attenuated at least 20 dB below the level of the unmodulated carrier."
Sometimes I wonder why the FCC exist's and who the hell wrote these rules? lol They seem to contradict themselves or just make it look that way.
What I am confused about is this, what can we do here? Is it worth the trouble? Is my math wrong, or is the power allowed under 15.223 2 mW?
I would bother to transmit here if I understood what the heck this section refers to.
Any idea?
and they lie above the AM Broadcast Band starting at 1.705 and ending at 10 Mhz. ( 1705 to 10000 )
Rule for this band is 15.223 and I quote it below:
§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 the purposes of this section, bandwidth is determined at the points 6 dB down from the modulated carrier. The emission limits in this paragraph are based on measurement instrumentation employing an average detector. The provisions in §15.35(b) for limiting peak emissions apply.
(b) The field strength of emissions outside of the band 1.705-10.0 MHz shall not exceed the general radiated emission limits in §15.209.
If i am correct in my calculations and i really don't do math well, then we should be allowed about 2 mW in this band however there is another section of rules that some how manages to confuse me.
15.219 Operation in the band 510-1705 kHz.
(a) The total input power to the final radio frequency stage (exclusive of filament or heater power) shall not exceed 100 milliwatts.
(b) The total length of the transmission line, antenna and ground lead (if used) shall not exceed 3 meters.
(c) All emissions below 510 kHz or above 1705 kHz shall be attenuated at least 20 dB below the level of the unmodulated carrier. Determination of compliance with the 20 dB attenuation specification may be based on measurements at the intentional radiator's antenna output terminal unless the intentional radiator uses a permanently attached antenna, in which case compliance shall be demonstrated by measuring the radiated emissions.
The last few lines of 15.219 says " All emissions below 510 kHz or above 1705 kHz shall be attenuated at least 20 dB below the level of the unmodulated carrier."
Sometimes I wonder why the FCC exist's and who the hell wrote these rules? lol They seem to contradict themselves or just make it look that way.
What I am confused about is this, what can we do here? Is it worth the trouble? Is my math wrong, or is the power allowed under 15.223 2 mW?
I would bother to transmit here if I understood what the heck this section refers to.
Any idea?