"Broadcast stations in the FM Radio Service, i.e., broadcast stations that transmit on a frequency between 88 and 108 MHz must be licensed by the Commission. 47 U.S.C., Sec. 301. The only exception is for certain low power stations in this band whose emissions do not exceed 150 micro-volts/meter at three meters as measured by instruments commonly referred to a field strength meter. 47 C.F.R., Sec. 15.239. The amount of power from Mr. Kobres' station far exceeds that provision in 47 C.F.R., Sec. 25.239 which permits certain very low power emissions in this band without a license. Transmitters operating in accordance with that regulation have a range of no more than 1000 feet. Mr. Kobres' station was received by me approximately six miles from the transmitter..."
Interesting comment about 1000 feet range. This is an excerpt from a sworn statement by Gerardo Daubar concerning the operation of an unlicensed station in Lutz, FL.
Also note the agent's misquote of the actual field allowance per 15.239: whose emissions do not exceed 150 micro-volts/meter at three meters
OK 1,000 feet is legal making the SainSonic AX-05B 100% legal. But was that to a Car Radio or Ghetto Blaster. If its a Ghetto Blaster that would mean you could be heard over a mile on a Car Radio. Now this would eaven the playing field to what AM is. Is my theory correct and this is how SainSonic was Legal at the advertised power on High? Did SainSonic JUMP THE GUN and the transmitter was NOT supposed to be released until This Year when the FCC finally stated 1,000 feet is legal and someone at the certification lab dropped the ball and went ahead and released the transmitter to the masses and it was much too late to put the genie back into the bottle? That is my assumption on that. But the statement of 100uV/M @ 3 meters??? That doesn't jive. I wonder if he meant 1000 uV/m @ 3 meters. Now that would get you 1,000 feet to a ghetto blaster. I can hear the other website now I'll have to see if there is any talk over there about this.
We doubt that the FCC uses either a Ghetto Blaster Boom-Box or any other portable or auto radio.
They don't? What if it had a 1 meter antenna? 🙂
Unrelated, I am getting lectured on FB about 1710. 🙂
Perhaps the FCC is reading this Forum and following our range calculations. 1000 feet is about the maximum you can hear a legal part 15 fm signal on the best car radios (on the best portables about 300-400 feet). Obviously a typo on the 150 uv/m part.
FB?
John, WDCX, can you patch those FB (Face Book) comments about 1710 over to this forum so we can be part of the jury of judges?
Reply to clip from Post #5 above, "What if it had a 1 meter antenna?"
The length of the receive antenna used by a calibrated field intensity meter does not need to have a physical length of one meter in order to measure received field intensity in units of V/m (or mV/m or μV/m).
It only needs to have a known antenna factor (AF) at the measured frequency.
For what its worth the fact that they are no longer thumping the 200 foot dialog is a great start for part 15 Radio. I guess our tests are the equivalent to the AM challenge mentioned elsewhere on the net. Our Transmitter shootout for FM and tests do bust some myths that has plagued part FM operators for quite some time. Now its just a matter of getting others on the same page rather they like it or not. You have to get these folks to realize in the real world one is not going to spend good money on a transmitter that will only go as far as the length of their arm. We still have a long way to go for anytime we talk about range you still read where someone chants the same old mantra OM you are a pirate your signal goes beyond 200 feet on FM OM repeat after me OM. They say if you tell a lie long enough you may get a few people to believe the lie. Especially if you rehearse it and pre meditate on the telling of that lie. Well I say some are sheep and some are shepherds of the sheep. So you have to decide rather you want to be sheep or shepherds here. I think it would be nice to have a pro FM site called shepherd Radio Forum for all you sheep who need correct guidance from someone who has an open mind and can see the facts as they unfold right in front of their face sure as the sun exists rather its a cloudy day or not. Its just your perception of the sun relative to your weather conditions in the space and time you are placed. Have you ever asked yourself why a carrot is oranger than an orange? Well we as real Radio enthusiasts need to think more scientific here.
Have you ever asked yourself why a carrot is oranger than an orange?
It's somewhere in the Bible.
If the FCC heard this guy's station six miles away then it is moot whether the agent thought the limit was 100 or 250 uV/m @ 3m since this was per se way over the limit.
It is, however, bothersome that the agent was thinking in terms of range rather than field strength at a distance which is what 15.239 specifies.
Neil
The FCC knows that the common man buyng a transmitter has no way to measure the field strength. So the whole 15:239 rule is MOOT if you can't accurately measure it. So now we seem to have a second rule 1,000 Feet! Does this remind you of the AM part 15 days all over again? If this, than that. Ask the salesperson at Walmart if the transmitter is 250 uVm @ 3 meters. Now if you ask how far it goes now I am sure some can answer that more so than the field strength. I tell you what why doesn't the FCC just give all us part 15 FMers a Patomac FIM 71? That wouold be better that way we all can follow their little 15:239 rule. Buy a part 15 FM transmitter and the FCC sends you a Patomac FIM 71 and its your job to make sure your not exceeding the rule. I think your gonna find a different stance really soon at the FCC field inspections for FM part 15. Field strength was a stupid thing to start out with. At least AM the rules are more clear and your able to follow them. Heck with the Talking House AM Transmitter its impossible to break the rules in its stock condition. Not so much with the present FM field strength BS going on. Want folks to follow that rule? I expect my Patomac FIM 71 in the mail complete with the calibrated antenna and everything I need to check my transmitter out. I'll be checking my mailbox daily lol.
At a bust of the party pirate the FSM used by the FCC "looks" like 1 meter
How many FSMs did the FCC bring?
1 meter.