MOT NFL Sideline system

radmano · Post by **radmano** » Mon Oct 29, 2001 7:09 pm

Does anyone know what type of system is employed with the MOT branded NFL coaches headphone com system?(ie, frequencies,modulation,etc)

mike38015 · Post by **mike38015** » Mon Oct 29, 2001 8:13 pm

The systems I have seen installed in our NFL stadium is a hard-wired closed system so it can't be monitored.

Mike

PRR · Post by **PRR** » Tue Oct 30, 2001 10:26 am

The NFL coaches communications system is made by Telex. The headsets are custom molded housings for Motorola but the internals are from standard HR1 series headsets.

For head coach to assistant coaches: The wireless system is a BTR-600 full duplex dual audio channel, 2 RF channel wireless intercom operating in the UHF TV band (520MHz - 760MHz). This system is 16 bit digitally encrypted. The coaches usually use audio channel 1.

For head coach to QB: Audio from the head coach's 2nd BTR-600 audio channel is routed to/from a standard Motorola repeater with the QB's radio built into the helmet. Approximately 30 (?) seconds prior to the play, an NFL official hits a remote switch to disable the repeater so the coach & QB can't communicate while the ball is in play.

Although the units can select between 2 RF channels, the system is crystal based and not programmable. The 2 audio channels are multiplexed onto a single carrier. The system allows for listening to both audio channels simultaneously, but talking on only 1 audio channel at a time.

All this Telex gear is from their Pro Audio division, NOT the LMR side.