"Within a concentrated area of downtown's core - mainly from Franklin Street to Ashley Drive and from Polk to Twiggs streets - people have been noticing that their car alarms either can't be activated, or can't be deactivated, sometimes disabling their engines. Downtown guides, police and tow truck drivers often must help push the cars out of the strange zone. Sometimes, the alarms set themselves off, sending shrill chirps into the air."
"After the St. Petersburg Times began looking into the phenomenon in April, the Federal Communication Commission also investigated. The Times recently obtained the results."
"According to the FCC, one of the radio antennas on top of the Colonial Bank building at 400 Tampa St. broadcasts oldies station WRBQ-FM 104.7. It uses a radio frequency that emits a harmonic, which is a byproduct of the main radio signal that occurs at a higher frequency. That harmonic might match the frequency that some car alarms use. The FCC's measurements concluded that the harmonic falls below the FCC's limits for frequencies, so the station isn't violating any rules."