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#41
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![]() John - KD5YI wrote: You are wrong about the FCC limits on 13 MHz. There is no mention of 10,000 uV/m. Here are the limits: Sec. 15.225 Operation within the band 13.110-14.010 MHz. (a) The field strength of any emissions within the band 13.553- 13.567 MHz shall not exceed 15,848 microvolts/meter at 30 meters. (b) Within the bands 13.410-13.553 MHz and 13.567-13.710 MHz, the field strength of any emissions shall not exceed 334 microvolts/meter at 30 meters. (c) Within the bands 13.110-13.410 MHz and 13.710-14.010 MHz the field strength of any emissions shall not exceed 106 microvolts/meter at 30 meters. You are also wrong about the power level required to achieve these limits. The power required is much lower. Cheers, John There appear to be two sets of part 15.225 rules floating around. http://frwebgate.access.gpo.gov/cgi-bin/get-cfr.cgi?TITLE=47&PART=15&SECTION=225&YEAR=2001&TYP E=TEXT shows: "[Code of Federal Regulations] [Title 47, Volume 1] [Revised as of October 1, 2001] From the U.S. Government Printing Office via GPO Access [CITE: 47CFR15.225] [Page 726] TITLE 47--TELECOMMUNICATION CHAPTER I--FEDERAL COMMUNICATIONS COMMISSION PART 15--RADIO FREQUENCY DEVICES--Table of Contents Subpart C--Intentional Radiators Sec. 15.225 Operation within the band 13.553-13.567 MHz. (a) The field strength of any emissions within this band shall not exceed 10,000 microvolts/meter at 30 meters. (b) The field strength of any emissions appearing outside of this band shall not exceed the general radiated emission limits shown in Sec. 15.209. (c) The frequency tolerance of the carrier signal shall be maintained within plus-minus0.01% of the operating frequency over a temperature variation of -20 degrees to +50 degrees C at normal supply voltage, and for a variation in the primary supply voltage from 85% to 115% of the rated supply voltage at a temperature of 20 degrees C. For battery operated equipment, the equipment tests shall be performed using a new battery." And http://www.fcc.gov/Bureaus/Engineering_Technology/Documents/bulletins/oet63/oet63rev.pdf Also shows the 10,000uV/M at 30M Yet http://www.sss-mag.com/pdf/part15-91905.pdf Dated sept 2005, shows the limits you quoted. What is troubling is the FCC has different specs on different documents at fcc.gov. Buy regardless of runinng 10,000uV or 15,848uV, one does NOT need a 100W transmitter to reach either of these levels. I have a 2W unit followed by a step attenuator coupled to a bufffer with a Zin of 50 Ohms and a Z Out of ~500. The buffer transistor is a 250mW and isn't even warm. This was the only easy way to allow the attenuator to accurately step the power level down. By the 15,848uV I guess I could increase my power from 5,000uV, to allow for the energy in the sidebands, to something like 10,000uV. Oh whoopy gea! Too much trouble to even think about changing as I had to back the exciter down to something like 1/2W to reach the 5,000uV level. Crystal Oscillator-buffer#1-amplifier-?20dB pad-step attenuator-buffer#2-matching- very poor radiator. I would guess I am running maybe 5mW into a modified CB ground plane antenna. Serious mismatch, but my "beacon" was only intended to reach about 1 mile. For an S2 reading I had to back the power down ~50% from max legal. So assume I am running 2.5mW with no attenuation, so for extra credit, what is my power level at -63dB? Terry |
#42
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#43
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"Dale Parfitt" wrote in
news:CKFCg.56002$gU4.47279@trnddc07: "Slow Code" wrote in message nk.net... "Dale Parfitt" wrote in news:R0aCg.15333$l95.9940@trnddc08: So if N9OGL's transmitions are legal power wise, he would basically be broadcasting for the kids across the street. Maybe he could take song requests. They can just shout out their front doors what songs they want him to play. SC I can copy perhaps 8 beacons on 13.555 MHz from all across the U.S. Assuming they too are running the power level Roy calculated, N9OGL's beacon should also be copyable. Dale W4OP You don't need to tell me the strengths of CW. I'm a CW advocate. Just listen to the NCDXF beacons on 14.100. You can easily hear the 100mW tone all over the world when there is propagation with a simple antenna. I'm just saying the RF Todd is puting into his antenna has to be quit low if he is transmitting legal power wise. Sc I too enjoy CW- probably 90% of my operating. My comment was that if his ERP is the same as the other beacons, then he will be heard well beyond "across the street". W4OP I'll try to copy a few of those beacons. Maybe there is info on about the stations, and possible they have a waiver for an increase in power or antenna size. Sc |
#44
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#45
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![]() John - KD5YI wrote: N9OGL wrote: Brenda Ann wrote: "John - KD5YI" wrote in message news:AqTBg.55239$Lh4.46900@trnddc02... Slow Code wrote: dxAce wrote in : N9OGL wrote: Not Lloyd wrote: wrote in message ... are you using an ex Ham transmitter? I hear with LSB/USB get further than AM but is the LSB really wide enough for quality audio? Got a grandpappys MP1000 here that will rag 50 watts AM all day long, but the band width is to narrow for anything like nice music audio... Speech is nice though. Maybe there is a wider AM filter than stock, some Ham wizardry to make it fit a decent audio element on to the carrier, ........................................... ........................... Transmitting on illegal frequencies with an illegal transceiver? Only stupid Toad would do that. Gather around the legal frequencies this evening at 14.331 as we get a forum of LEGAL Hams together to discuss the nefarious activities of Toad and Roger. Look for this forum to begin on or about nine p.m. eastern time. Toad cannot join in, nor can KB9RQZ, since they are not licensed for this freq. Roger needs no invitation...he will lurk and jam as he sees fit. Before you go around spouting that I'm running illegal, I would suggestion that you read Part 15 (47 CFR 15) but more to the point 47 CFR 15.225 How much power you running? Unable to hear you here, but I'll give a listen again tomorrow if you're still up and running. 10000uV/m at 30m is the maximum. How much power into an isotropic radiator give 10000uV/m at 30m. Of course, when the antenna has gain, power has to be reduced to avoid illegal operation. My guess is 3 mW. John The level is the same as emissions within the CB band: Sec. 15.227 Operation within the band 26.96-27.28 MHz. (a) The field strength of any emission within this band shall not exceed 10,000 microvolts/meter at 3 meters. The emission limit in this paragraph is based on measurement instrumentation employing an average detector. The provisions in Sec. 15.35 for limiting peak emissions apply. (b) The field strength of any emissions which appear outside of this band shall not exceed the general radiated emission limits in Sec. 15.209. I don't know that there is a difference anymore between Part 95 and Part 15 emissions in the CB band... the old Part 15, back when a license was required, used to be 100mW. PART 15 in the CB band is 10,000 uV/meter @ 3 meter (100 mw).(Walkie talkies and cordless phones are also 10,000 uV/meter @3 meters) While on 13 MHz it's 10,000 uV/meter @ 30 meters or about 1.8 watts at 100 feet. Todd N9OGL OMEGA ONE RADIO You are wrong about the FCC limits on 13 MHz. There is no mention of 10,000 uV/m. Here are the limits: Sec. 15.225 Operation within the band 13.110-14.010 MHz. (a) The field strength of any emissions within the band 13.553- 13.567 MHz shall not exceed 15,848 microvolts/meter at 30 meters. (b) Within the bands 13.410-13.553 MHz and 13.567-13.710 MHz, the field strength of any emissions shall not exceed 334 microvolts/meter at 30 meters. (c) Within the bands 13.110-13.410 MHz and 13.710-14.010 MHz the field strength of any emissions shall not exceed 106 microvolts/meter at 30 meters. You are also wrong about the power level required to achieve these limits. The power required is much lower. Cheers, John That's the revised version updated in 2006, the old version was 10,000 uV/m @ 30 meters. Todd N9OGL |
#46
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#47
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![]() John - KD5YI wrote: wrote: I would guess I am running maybe 5mW into a modified CB ground plane antenna. Serious mismatch, but my "beacon" was only intended to reach about 1 mile. For an S2 reading I had to back the power down ~50% from max legal. So assume I am running 2.5mW with no attenuation, so for extra credit, what is my power level at -63dB? Terry Your question makes no sense. What is the reference level? 1 watt, 1 mW, 5 mW, 2.5 mW? .5 microwatts is 63 dB below a Watt. .5 nanowatts is 63 dB below a milliwatt. 2.5 nanowatts is 63 dB below 5 milliwatts. 1.25 nanowatts is 63 dB below 2.5 milliwatts. (Is this the one you want?) 2.5 milliwatts is 3 dB below 5 milliwatts. See a pattern in any of this? Once again I see why I should not take up comedy. It wasn't a serious question. I was reffereing to 5mW at 50 Ohms. Terry |
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