I’d been fixing to generally ignore this story but it’s been syndicated far and wide. When my mom said she read it on page two of the hometown daily the extent really sunk in. It’s a propaganda coup for the broadcast industry.
The main thrust, that pirate radio stations interfere with airplanes, gets hammered home quite nicely. In this particular case, involving a station in Miami that squats two FM frequencies, it should come as little surprise. In fact, with 20+ pirate stations operating in the Miami area alone, you are bound to encounter some problems with interference, in-band or otherwise.
This is not to condone sloppy operation. Retards like those running “Da Streetz” give everyone a bad name. It has happened before in Florida and elsewhere. But it is important to weigh the sensational nature of this story against the relative risk of the problem it describes.
Interference to aviation radio channels from an FM station is usually caused by spurious emissions generated within the transmitter itself. If these emissions are amplified, the problem gets worse. Thus full-power stations broadcasting with thousands or tens of thousands of watts are much more likely to cause this type of interference than a pirate broadcasting with a fraction of that power.
Aircraft flying closest to the offending transmitter have the greatest chance of encountering interference, but it is by no means universal, as a Federal Aviation Administration spoke admits is the case in Miami. She also claims the agency has investigated some 30 complaints involving pirates and aviation-related interference over the last decade. It would be helpful to know how many complaints the FAA received about full-power licensed stations over the same period, so as to put the pirate problem in proper perspective.
When interference occurs to an aviation radio channel, pilots and air traffic controllers will switch to an alternate frequency. Aviation radio communications are redundant like that. Broadcasters solve spurious emission problems by replacing their transmitter and/or installing a low-pass filter to attenuate the problem spur(s). Responsible broadcasters, licensed or otherwise, run filtered signals by default.
This places broadcast radio interference relatively low on the scale of actual danger to aircraft. High-risk emissions are those that interfere with an aircraft or airport’s radio-navigation and instrument flight control systems. These are typically not redundant; losing them, especially in inclement weather or at night, has the potential to create a real mess. To my knowledge pirates have never been accused of interfering with such systems, but commercial stations have.
The worst potential interference to aircraft actually comes from within the plane. Analysis of the RF environment inside airliners notes several common electronic devices cause interference to critical flight control systems: cell phones, laptop computers, and portable DVD/game consoles.
Even so, the FCC plans to move ahead this year with an initiative to allow the deployment of cellular and wireless internet access on aircraft. So, who’s the hypocrite?