A little FYI for those who may not know yet.
My company along with many radio companys all over the country are in the process of getting all commercial/public safety type frequencies re-licenced for narrow band and making sure all of their radios are narrow band capable or replaceing them with one that are. This also includes base and repeater systems.
Some of these repeaters have ran 24/7 for over 20 years or more and complete communication rooms are getting completely replaced, duplexers and all if they are old enough.
Good info at this link, or just google it or whatever.http://www.ojp.usdoj.gov/nij/topics/technology/communication/fcc-narrowbanding.htm
I searched and did not see anything here so ..for what it's worth ..thought I would share,we have replaced a lot of good quality radios with narrow band capable ones.