The average person has likely driven by a billboard hundreds of times in their lives, if not several times every day.
But what they may not know is that these common advertisement spaces for local businesses may also be transmitting low power radio signals.
Larry Lanberg, a visitor to my site who lives in the Richmond, VA area, recently contacted me regarding an unidentified signal he was receiving on 1620 AM after he couldn’t find any stations on that frequency in our state (there are no commercially-licensed 1620 AMs in Virginia). The only match he found was my logging of 1620 WPMU747 Lorton, VA, a low-power traffic information station operated by the Virginia Department of Transportation.
But something wasn’t right. Lanberg said that he heard “snippets of songs” and a pre-recorded message mentioning the Virginia Lottery on the station–something I know VDOT traffic signals do not air. Plus, the likelihood of the relatively weak 10 watt signal from WPMU747 reaching the Richmond area, at over 70 miles, was highly unlikely. The existence of other VDOT traffic signals on 1620 AM in the Richmond area which likely do not air music made this an even larger mystery.
My 
