On January 11, Arbitron will release the very last radio ratings for Philadelphia that will be produced by paper-and-pencil diaries. The new electronic Portable People Meter (PPM) ratings service will be initiated in Philly on January 11. The Fall 2006 book is being designated the ?currency? in the market until the release of the March 2007 PPM ratings report. The January 2007 and February 2007 PPM ratings are to be released as demonstration data…Instead of Winter Phase 1 and 2 Arbitrends reports, subscribing stations will receive monthly PPM-based audience estimates using the installed PPM sample, which is planned to be 2,040 persons, age 6 and older.