To no one’s surprise, Entercom has countersued to keep talk host Howie Carr from leaving WRKO-AM Boston for Greater Media’s WTKK-FM. The Boston Herald reports that the lawsuit against Carr and his agent was filed Wednesday, claiming that they conspired to break his contract with Entercom by negotiating with Greater Media. The dueling lawsuits come down to one main point – whether the provision in Carr’s current contract giving Entercom 72 hours to match another offer is legal in Massachusetts. Entercom’s lawyers say it is. Carr’s lawyers say it isn’t.