if you're using wifi then try another wifi channel if many wifi networks close by all run on the same channel they can disturb each other
also if you can try using 5Ghz wifi rather then 2.4Ghz try that dect landline phones, microwave ovens, bluetooth and the likes all run on 2.4Ghz and that can cause disburbance
you can also troubleshoot by connecting the macbook and appletv by ethernet cable and a switch or router to see if it works flawless then if so then you know the culpit is your wifi network