My Tablo (2 tuners) sitting on its side vertically reads 94F on the bottom plate at the hottest point when idle.
It reaches 104F when actively being used.
However, it's hardwired to my network.
If it was connecting to my network wirelessly, it would get even hotter, because the wireless chip would generate heat, too.
Is your Tablo connecting to your network wirelessly?
If it is, then it's definitely within the normal temperature range.
Also, the ambient room temperature, and humidity affect the Tablo's temperature.
Hotter the air in the room, and, or higher the humidity, the higher the Tablo's temperature will get.
Same applies to all electronics, like your computer.