field devices are wireless microphones but other similar transmitting devices could be used 6 crew a has a wireless microphone system that can operate in uhf channel 40 to 45 626 mhz to 662 mhz 7 crew b has a wireless microphone system that can operate in uhf channels 20 to 25 506 mhz to 542 mhz 8 the chief engineer submits a list containing the identification codes of the two wireless microphone systems to the frequency coordinator via e mail 9 using the existing local database in conjunction with any other potential user of the same spectrum the frequency coordinator makes a determination of a the best possible uhf channel for each wireless microphone b the best possible sub channel within the uhf channel for each wireless microphone based on first adjacent channel interference second and third order intermodulation products and other factors 10 the frequency coordinator then communicates with the ce via e mail or other means identifying the specific frequencies the ce has been assigned to assure that both the wireless microphones and the receivers that will be used are physically capable of being tuned to those exact channels for example the assignment may be for channel 510 530 mhz but the equipment might only tune to 510 525 mhz 11 the ce then approves the channels or replies with a negative response in which case the frequency coordinator makes a new assignment 12 if the channel assignments will work for all the ce 39 s equipment the assignment is valid 13 the frequency coordinator then sends a verification e mail to the ce with an individual unique text message code the code is to be used just prior to the ce powering up his wireless microphones 14 the frequency coordinator.