Here's a forfeiture order I found on the FCC site. This one is interesting because many details are available in the order.
The person cited apparently was using a low power transmitter. [Note that the powers here are my calculated values from the multiples of legal f.s. in the report] From information in para. 2, 1719 times the legal field strength would result from about 33 mW. ERP. After his first notice, he lowered his power and kept operating. From para. 5, he used 2.1 mW. and continued operation. From para. 5, following his second notice he lowered power to 80uW. and was still 85 times the legal limit.
In para. 6 he states that he believed he was working with the agent to determine when his field strength would be legal. The FCC says they are not obligated to do this.
Interestingly, in para 7, the FCC states that he was told to get a part 15 wireless microphone and compare the range of his station to this.
The result of his continued operation is a $10,000 fine.
Several things here stand out to me. First, the field strengths (powers) involved here are easily obtained by FM transmitter kits with simple antennas. Second, it is not valid to believe that the FCC agent will work with you and help you adjust your transmitter. It is also not wise to continue operating after being contacted by the FCC.
I don't know what attracted the FCC's attention in the first place but it is clear that the offender's response in this order was not acceptable.
I speculate that if he had set his station for about a 200 foot range in the first place he probably would not have been cited, and if he had ceased operation after the first contact with the FCC that would have ended the matter. Also, his petition for dismissal was denied because he didn't respond in a timely manner. Don't wait to reply to a FCC letter.
Something to think about.
Neil
The FCC recently issued three NOUOs to three remarkably powerful FM stations in the Ft. Lauderdale, FL area. I think these three stations were part of the same enterprise, although the NOUOs don't actually say that.
http://www.fcc.gov/eb/FieldNotices/2003/DOC-276084A1.html
http://www.fcc.gov/eb/FieldNotices/2003/DOC-276085A1.html
http://www.fcc.gov/eb/FieldNotices/2003/DOC-276086A1.html
The field strength readings are equivalent to radiated power from a half wave dipole of 29 kW from the first station, 57 kW from the second station (!), and 28.9 kW from the third station.
In a previous post in this thread, I called big and little pirate transmitters "sharks and little fish." These three stations should be called "leviathans" or "behemoths" because the simile should be to considerably bigger aquatic animals.
Ermi,
It is hard to imagine that a pirate would be able to achieve the ERPs that you reported (and I verified by calculation) so I wonder if something else is going on. Maybe they have a construction permit and jumped the gun on the power switch? Otherwise, there must be some heavy duty financing (and ignorance of the FCC rules) going on. I am certain that I don't know the whole story about this.
Neil
My first thought on reading that report was to wonder what sort of pirate station could afford even just the electric bill for that kind of power.
Maybe they're using a considerably lower level of power with a high gain directional antenna? If they were doing that from a distance outside some city or whatever they're actually trying to cover, maybe they thought it would make them harder to catch?
FM wavelengths are small enough that high gain antennas are reasonably practical, but still they'd have to be pushing a sizable amount of power I would think.
Also kind of had to wonder at the coincidence of two of those stations both being measured at a distance of 321.9 meters. Is there anything in particular about that distance that anyone knows of?
In any case though that's a lot of juice, even if it was a gain antenna.
Daniel
not so. as i understand it, this is normal for florida. ever hear of L.D. Brewer??? The Party Pirate???
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Daniel wrote: Maybe they're using a considerably lower level of power with a high gain directional antenna?
________
A 9-element Yagi-Uda (for example) has a linearly-polarized peak gain of about 10 dBd, which is a power gain of 10 X. The antenna input power needed to produce a maximum radiated power of 29,000 watts then will be 29,000 watts/10 = 2,900 watts.
And if they were using a transmitter rated for 35 milliwatts, then ignoring coax attenuation and matching losses, a directional antenna would need a gain of 828,571 times, or 59.2 dBd to radiate a maximum power of 29,000 watts. And the main lobe of that radiation pattern would be extremely narrow.
Such an antenna is highly impractical in the band 88-108 MHz.
//
I was thinking much higher than 35 milliwatts, Rich. More like maybe they'd adapted something like 2 meter ham gear or something with an output more like 500 to 1000 watts. It just seemed to me that a 29 KW station would be *very* expensive to operate just in terms of the electric bill.
Daniel
Daniel - Under perfect conditions, the power gain needed for 29,000 watts peak radiated power with an antenna input power of 1,000 watts is 29 X, or 14.6 dBd, and twice that (58 X, 17.6 dBd) for 500 watts input power.
Theoretically that might be achievable over a small coverage sector on the FM band, but it would take some heroics to do it (an array of critically-phased yagis, for example).
//
An interesting NAL was issued on October 2nd by the FCC to a pirate who claimed to be operating a Part 15 station:
http://www.fcc.gov/eb/FieldNotices/2003/DOC-277176A1.html
NALs contain a lot more information than NOUOs, and so, they make more interesting reading. The same offender was arrested by Federal Marshals ten years ago, and his equipment was confiscated. He operated an unlicensed station in Philadephia on the same frequency, using the same made-up call letters.
The NAL does not state the field strength reported by the agents, so I found the NOUO related to this NAL:
http://www.fcc.gov/eb/FieldNotices/2003/DOC-268242A1.html
The equivalent radiated power from a half wave dipole was only 6.8 mW. This is quite a bit less power than I expected, since it was a commercial station broadcasting Hip Hop music and advertising. The agents observed an FM broadcasting antenna on the rooftop of the offender's home.
Well, with a range of 3-5 miles, pretty much no way it could be within the parameters for legal part15 FM.
What I've wondered with some of these cases is why there's a tendency to measure the field strengths at around 300 meters distance. Ok, maybe can't do it from 3 meters if the person won't allow them in to inspect it.. But 300? If you can knock on his door, you're a lot closer than 300. I'd think they'd measure from as physically close as they can get, to avoid multipath throwing the reading off. Ok, sure.. multipath couldn't more than double it or halve it and so in this case it's still a clear violation, but 300 meters seems to be a trend. Any ideas on why?
In any case though, part 15 FM isn't going to provide a range of 3-5 miles even under phenomenally good conditions. Considering urban terrain and a congested FM band in Philadelphia, even a range of a block to something sensitive like a good car radio would be surprising.
Daniel
Hi Daniel,
You wrote: What I've wondered with some of these cases is why there's a tendency to measure the field strengths at around 300 meters distance.
It has been many moons since I was an invited guest in a FCC monitoring van but I do remember that the equipment was bulky and rack mounted. It would be rather difficult to drive the van into a dwelling or onto a roof to get to within 3 meters of a radiating element.
All they have to do is demonstrate that the radiation exceeds the 250 uV/m limit at a distance beyond 3 meters. If, for example, the measurement is 3000 uV/m at 100 meters then any rational person will accept that it is over 250 uV/m at 3 meters. Though the actual FS at 3 meters is not measured it is clear that this example operation exceeds the limits.
If you read the NOUOs on the FCC site, you will conclude they are not dealing with operators who are "just a few uV/m" over the limit and it would be very difficult to argue that multipath or other effects biased the measurements to an extent that a legal operaton would appear to be in violaton.
Neil
An NAL I mentioned a few months ago in this thread has matured into a Forfeiture Order (for $10,000):
http://www.fcc.gov/eb/Orders/2008/DA-08-521A1.html
This particular offender did not reply to the NAL, but wrote to a U.S. Senator instead, possibly hoping to get the same deal the famous Nevada pirate got by writing to Sen. Harry Reid.
An NAL I mentioned a few months ago in this thread has matured into a Forfeiture Order (for $10,000):
http://www.fcc.gov/eb/Orders/2008/DA-08-521A1.html
This particular offender did not reply to the NAL, but wrote to a U.S. Senator instead, possibly hoping to get the same deal the famous Nevada pirate got by writing to Sen. Harry Reid.
Used a 120 watt transmitter to an antenna on an 80 foot tower. The antenna was a Comet 5/8 antenna. So assuming a advertised "3db Gain" over a dipole his ERP was 240 watts. This did not take into account loss from the coax.