Londonbased Cellnet Ltd will almost double the capacity of its Midlands cellular network by adding an extra 1,300 voice channels, representing a 10% increase in capacity for the Cellnet system as a whole: by the end of this week, Cellnet intends to have brought in 18 new cells and added new extra channels to 41 existing cells; Cellnet warns that there may be some temporary disruption to the service in that region this week while the retuning of frequency channels is carried out.