A History of Encroachment on LPFMs

Both full-power FM and Translator stations can move closer to LPFMs, than LPFMs can move toward those stations, resulting in the LPFM being "short spaced" -- possibly receiving interference or in the worst case the LPFM must shut down. We call this situation "encroachment" and this graphic is one view of historical encroachment.

→ Full-resolution Graphic.

With a proper waiver, LPMFs are allowed to select short spacing on a second-adjacent channel with a full-power station or translator. This graphic does not distinguish who requested the short spacing.