Communications troops don't get nearly the amount of love that they deserve. Sure, the job description is very attractive to the more nerdy troops in formation and they're far more likely to be in supporting roles than kicking in doors with the grunts, but they're constantly working.
In Afghanistan, while everyone else is still asleep, the S-6 shop is up at 0430 doing radio work. This is just one of the many tasks the commo world is gifted with having.
The reason they're up so early is because they need to change the communications security (or COMSEC) regularly. In order to ensure that no enemy force is able to hack their way into the military's secure radio systems, the crypto-key that is encoded onto the radio is changed out.
Those keys are changed out at exactly the same moment everywhere around the world for all active radio systems. Because it would be impractical to set the time that COMSEC changes over at, the global time for radio systems is set in Zulu time, which is the current time in London's GMT/UTC +0 time zone.
For troops stationed in Korea or Japan, this gives them a pleasant 0900 to change the COMSEC. Troops on America's west coast have 1600 (which is great because it's right before closeout formation.) If they're stationed in Afghanistan however, they get the unarguably terrible time of 0430.
Each and every radio system that will be used needs to be refilled by the appropriate radio operator. When this is just before a patrol, the sole radio operator with the SKL (the device used to encrypt radios) will usually be jokingly heckled to move faster. The process usually takes a few minutes per radio, which could take a while.
This is also why the radios themselves are set to Zulu time. If the radio is not programmed to Zulu time — or if it's slightly off —it won't read the encryption right and radio transmissions won't be effective. This goes to the exact second.
So maybe cut your radio guy some slack. The only time they could be spending sleeping is used to program radios.