Blue Harbor Group, run by Clifton S. Robbins, has a 2.5% stake in Tribune (TRBAA) and is urging the company’s management to sell its real-estate holdings and spectrum it owns. Mr. Robbins calls his TRBAA investment his “best idea for 2014”. TRBAA, as we have previously covered (Link), is spinning off its newspaper business already. Blue Harbor believes that Tribune should sell its spectrum, the valuable airwaves the company’s broadcast networks control. The spectrum is currently being underutilized, as it could carry wireless-phone signals. The spectrum it owns is located in big cities such as Chicago, Los Angeles and New York. Any plan to sell spectrum may be on hold for a while until the FCC officially determines if broadcast stations are even allowed to sell their spectrum. As a reminder, Tribune emerged from bankruptcy protection in late 2012.