airplay disconnects every hour

I have a late 2013 MacBook Pro running OSX Mavericks 10.9.2 connected using AirPlay to an updated AppleTV. I am NOT running battery power. Using iPhoto I am playing a slideshow on the TV. The slidewhow runs seamlessly but the AirPlay connection automatically disconnects every hour (exactly one hour).

It is not a networking issue associated with any latency or interference. There are no other devices on the wireless network; the environment is free of other sources of competing RF energy. I have no overlapping channels, competing radios or other sources of RF energy in the same frequency range (I live in the country and the nearest home is more than 1/2 mile away). There are no operating microwave ovens, bluetooth devices, cordless phones, baby monitors or other potential competitors in the area. Even if such interference were present it would not account for an interruption that occurs at exact 60-minute intervals. To further prove this I have verified that the problem still exists when connected via Cat5e.

When the AirPlay connection is broken the slideshow continues to play on the MacBook. If I stop the slideshow and re-start it the mysterious 60-minute disconnect counter does NOT reset; it still disconnects exactly one hour after the AirPlay connection started. This suggest the issue is not a timer or setting in iPhoto.

I tried unchecking the "Automatic graphic switching" box in the Energy Saver section of System Preferences but this actaully caused a random freeze in the slide show.

I suspect there is a setting somewhere that I am unaware of or have overlooked. Has anyone had this problem or can you suggest a fix? There are lots of posts on the Internet of people having AirPlay disconnect at irregular intervals but I cannot find one that addresses a non-networking-related every 60-minute disconnect.

Any insight will be appreciated.