Narrowbanding – the freeing up of certain frequencies is happening now. It started shortly after the 9-11 Commission issued their report on the country’s response to the terror attacks of 9-11. They needed to free up the 700 mhz frequency to allow for use by professional emergency responders. If you recall, June 12, 2009 was the date (original date was in February of 2009) that everyone needed to switch their TV’s over to a digital signal. The move is also on to narrowband land mobile radios starting in January of 2011 – eliminating use of the 150-174 and 421-512 mhz frequencies.
Wireless microphones are also subject to the narrowbanding rules. If you are seeking to purchase two-way radios for your SEMS, NIMS or emergency plans, make sure that they meet the requirements of narrowbanding. Some vendors may still be trying to move old stock, so be careful.
Here are some good links on the topic….