View Full Version : Flordia FM pirates
03-19-2006, 09:26 PM
I read on CNN some goof is messing up aircraft radio messages with a pirate FM transmitter Flordia... Hope the operators get off the air or do someting to stop the interferance or we will all take the heat for it.
03-19-2006, 09:44 PM
State, Feds Combine For Pirate Radio Crackdown
(CBS4 News) MIAMI Radio listeners like to complain that commercial radio stations tend to play what makes money, not what they like to hear, and that’s unlicensed, pirate radio stations enjoy a large following in many urban areas, including South Florida. But now, efforts to crack down on those shadow stations are stepping up, after some of the stations have allegedly begun to affect air traffic entering and leaving Miami International Airport.
What pilots are hearing in their headsets is not the control tower, it’s hip-hop, coming on a pair of frequencies from a station that calls itself Da Streetz.
CBS4 News Partner The Miami Herald reported Sunday that authorities traced the signals to a large radio antenna on tower mounted on a nearby warehouse in a Miami suburb, but did not find a radio transmitter or disc jockey.
One step ahead of the law, the people behind Da Streetz remain on the air, interfering at times with communications between pilots and the control tower.
"It's intermittent. Not all day, everyday," said Kathleen Bergen, a Federal Aviation Administration spokeswoman. "But clear communication between air control and the pilots is a critical part of flying."
Pirate radio stations don’t actually broadcast on the frequencies the pilots use, which are well outside the normal broadcast band which people can receive on their stereo. But since pirate stations are not regulated by the government or held to any technical standards, their signals can sometimes cause interference with radios on other frequencies, including those used by pilots.
Interfering with those signals is a federal crime.
The Federal Communications Commission and Florida Department of Law Enforcement are helping in the investigation. The FAA said it has conducted about 30 similar investigations into pirate stations interfering with airport transmissions in the past decade.
A Florida anti-piracy law went into effect a year ago that makes it a third degree to felony for anyone caught sending transmissions that interfere with signals from licensed public or commercial stations, or broadcasting without a license.
At the warehouse, state agent Joseph Zeller confiscated three computers, a monitor, a mixing board, a stereo compressor, microphone, a two-deck CD player, a telephone, a DSL modem, two stereo speakers and 10 cases filled with CDs.
Authorities said the owner of the warehouse had no idea the building was being used by an illegal radio station.
03-20-2006, 07:14 AM
They better not mess it up for the rest of us thats all I can say..All it takes is is one bad apple, got to mess it up for all of us. Time to go after them our selves.
03-20-2006, 01:54 PM
I know what kind of idiots are messing with aircraft transmissions?
Don't they realize what they are doing is dangerous? An aircraft not being able to contact the control tower could be a deadly situation.
Besides how many digital radios tune beyond 108 MHz anyways I don't know of any without modification. Maybe analog radios would be able to tune a little off the band but not much.
Who looks for radio stations off the FM band anyway?
[ March 20, 2006, 02:55 PM: Message edited by: krankshaft ]
03-20-2006, 07:35 PM
it's not that these people are broadcasting on a higher frequency than the fm band, it's the harmonics from their transmitter that broadcast higher up on the band. They really must be using some high power equipment because the harmonics of a fm25b or fm35 or the 100 dissipate very rapidly from the broadcast antenna. If I broadcast at 100.1, my harmonics are at 200.2, etc. There are odd harmonics,even harmonics, harmonics above band and below band. 2nd order harmonics, third order, etc. the air band is 108 to 136. It's pretty hard to interfer with aircraft when broadcasting on the fm band. Inless you have lots of power and a very dirty signal. Thats why you use filters and stay AWAY from broadband amps. The no tune, broadband rf amps are a no no. I guess if you used those amps you better have some good filters. Some people may indeed broadcast past 108 and yes they should be stopped. anyone with some class and sense knows they should not broadcast if they are interfering with aircraft. Thats just stupid and ignorant. Do a google search on harmonics, there is too much information on the subject. Remember, regular fm broadcast stations broadcast with thousands of watts and do not not cause harmful interfernce with aircraft. So if your mad because some other guy has more power than you, if his signal is clean than he or she is cool. Don't blame them for giving broadcasters a bad rap.
03-20-2006, 07:43 PM
Ah second order harmonics the multiple of your signal which appears in the aircraft band from what I read it seemed like they were intentionally broadcasting above the FM band.
[ March 20, 2006, 08:51 PM: Message edited by: krankshaft ]
03-20-2006, 08:10 PM
Just a technical clarification. A harmonic is an integer multiple of a signal frequency. The interference to aircraft radio is not due to a harmonic of the carrier frequency from the FM band since the second harmonic would fall far from the aircraft band in frequency. Second order, third order, etc. refer to intermodulation distortion (IMD) which is caused by unintended mixing in a receiver due signal overload.
The interference in this case is most likely due to what is known as a spurious emission. VHF amplifiers, especially broadband amplifiers, are susceptible to this because they can oscillate at frequencies unrelated to the signal carrier frequency. For example an amplifier processing a 100 MHz. signal and oscillating at 25 MHz. will produce strong spurious signals at 75 and 125 MHz. The comment that the interference is only heard occasionally is probably due to the fact that the oscillation in an amplifier is not frequency controlled and varies from one moment to the next, thus the spurious frequency also varies.
This is just my attempt to explain some of the terms which may apply here.
03-21-2006, 02:04 AM
As a pilot and part 15er I think there is a bit of misinformation here. There is no excuse for deliberately operating any transmitter when you know it is causing interference. However pirate stations are getting a little too much blame. If you do some research you'll find the worst case of FM broadcast/aircraft radio interference involved two commercial stations. I could only find one example of an unlicensed low power station causing interference in the aircraft band and in order to experience the interference a helicopter had to hover over the transmitting antenna. I hope the offending station in Florida does shut down as it generates nothing but bad press for the rest of us. On the other hand some law enforcement agencies in Florida do have an agenda when it comes to unlicensed broadcasters and use the term "pirate" even for part 15 compliant broadcasters. There's a lot of hype about unlicensed broadcasting and most of it comes from Florida.
03-21-2006, 06:57 AM
Just to clarify techpuppy, these guys cannot even be compared to people like us running mW signals... These guys get there hands on commercial broadcast transmitters and amplifiers and are running thousands of watts.
And as far as the interference, let me add two cents and WHY these guys are such nuisances... There is a way of signals mixing that can cause interference almost ANYWHERE... When you have two strong signals and you mix them together, you get FOUR resultant signals. You get the original two, the sum of the two and the difference. Example: 93.1 and 103.7 mix to result in 93.1, 103.7, 196.8 and 10.6 Mhz.
This mixing can happen in MANY places... but the likely culprits in the case of a pirate with questionable engineering practices is in HIS transmitting setup. Signals from other stations (not just broadcast, but police, cell, etc) can come down their antenna and right into the final amplifier stage of the transmitter and mix there... Or if the antenna is aluminum and has some oxidation corrosion, it can happen in the antenna as two pieces of metal and a little aluminum oxide under power makes a 'hot diode'.
I speak from experience on this as I have been tracking down 'intermod' (intermodulation interference) for years. One can go crazy with a calculator trying to add and subtract frequencies trying to find where the offending frequencies are coming from. The intermittent nature confounds the problem, but can often exist because one of the transmitters may not be on all the time. And air temp and humidity can change the properties of the 'mixing diode' and other such things.
Sometimes it is worse... I picked the frequencies for my example above on purpose... With a difference of 10.6 Mhz... you can wreak HAVOC on a HUGE number of radios! WHY?? Because a great many receivers, especially two way radios and scanners, use a IF (intermediate frequency) inside their circuitry of 10.7 Mhz. If a strong signal close to 10.7 got into receivers, it would not matter what frequency the receivers were tuned to... they would show up across the band.
The moral to the story is... good engineering practice, low power levels and a reasonable approach. By adding good filtering to your transmitter, you not only prevent "spurious emissions" that Neil mentioned (the biggest problem by far), but you also keep other signals OUT of your transmitter resulting in completely different frequencies being broadcast. And at power levels of less than a watt, you keep the odds of the later WAY, WAY down... But I have seen this kind of interference at levels as low as 25 watts or less.
Also, don't ignore the idea of a 'clean' antenna system. I once had a repeater system (both transmitter and receiver on two different frequencies) that was getting interference. The problem turned out to be that my own transmitted signal was mixing with an AM broadcast transmitter located in the valley right below it and the "difference" of the two signals when mixed, was 10 kHz away from my receiver frequency. It didn't happen at night, when they shut down or went to low power and it disappeared after a rain... I had proper filtering, so it wasn't happeneing in my transmitter... You know where it was happening? My OWN antenna!!! Yep. The proof? I took the antenna down, cleaned it, applied some aluminum de-oxidizer and viola! No more interference. (The rain wet the oxidation and shorted the 'diode'. When it dried out, it came back.)
RF is weird... and complicated. If you are not an expert, keep it way down low. Licensing exists to ensure good engineering practice, not just as a speech rights issue. Normally, I would say that regular law enforcement has no business in radio enforcement matters, where it takes engineering skill to often discover the true source of a problem... But in the case of 50,000 watt pirates, a threat to public safety and an overworked FCC... I think they should let FDLE go after them as long as it stays just high powered pirate radio... If there is not a threat to the public, or a massive nuisance, leave it to the radio engineers to figure out.
The soapbox is creaking, so I'll get down now... JMHO. :D
03-21-2006, 05:05 PM
what do people consider as a definition of pirate?
Is it power that is above 10mw? Is it the guy in the mountains with 5 watts? Or maybe what he is broadcasting, profanity, anti US sentiment? Or are we talking a 1000 watt dude with dirty equipment? Maybe a combination of several things? I personally think if a person is broadcasting 1 watt, has a clean signal, meaning he can drive around with a nice scanner and antenna and not here his stuff on the next channel or on the airband or 30 to 70 mhz or the 144 to 174 band,etc. and is not broadcasting bad taste stuff, then that person probably is ok and I don't have a problem. Some person with a 50 watt exciter or higher, to me is indeed just trying to be obnoxsious (sp) and is really going against established protical. I try to think if I was on some jury judging a person busted by the FCC, was it truly out of the spirit of the norm. I don't mean to excuse ignorance or just hap-hazardly broadcasting, but a person like us. I don't know if these type cases even get to a jury, but I certainly want to take all the circumstanses into concederation. I don't want to bust a person and then go home and do basically what they were doing. I read a bust story where the FCC told the local paper that they found a PCP pipe running from studio to antenna. Was it just a mis-spelling or did the feds or local police want to include that to make it seem the person was a druggie and a pirate, going hand and hand. The local community thought this person WAS doing drugs and broadcasting. It's so easy to ruin someones life by just doing something like that. Pirate makes me think of real pirates and the bad stuff they do on purpose. So a pirate radio station is someone just out there to mess with things with no regard of repercussions. Anyway just trying to get a definition of what we guys on this forum really consider a pirate broadcaster is. You know, I would love to broadcast in short wave and go around the world if skip is right, and have my stuff heard. Can I do that with out being a pirate? Yes I would have to have some bucks though. Why do only the big guys get to do that neat stuff?
03-21-2006, 06:24 PM
My opinion... two points:
1 watt or less... not trying to be a pirate. Guideline of 1 watt propsed by FCC for license free, but knocked down by Congress/lobbyists.
Total disregard for rules and others right... pirate. Considerate and willing to shut down as soon as notified... not a pirate.
If only it was so easy to put such things into law. :(
03-21-2006, 08:40 PM
Captan hook was a pirate
03-21-2006, 10:03 PM
Captain hook was a pirate
Read with thick pirate brougue: "ARRRRRGH, Matey! And he put out a really nice signal, too!"
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