I was trying to record a football game this past weekend on the local FOX affiliate and kept getting a low or weak signal error. I was unable to watch the game live or record it and yet when I checked my channel line-up it showed 5 green dots which I thought meant a full strength signal. Any idea what the issue might be???
The number of green dots only represents the signal strength at the time of the scan. So I would recommend rescanning your channels to make sure the signal is still good.
But before you do that, just reboot your Tablo. That might fix the issue too.
Television signals traveling through the atmosphere have highly variable signal losses. You can not depend on a somewhat weaker channel to be reliable enough for recording.
As to the meaning of the 5 green dots, here is my best explanation:
See: Researching DTV Reception
Update: You can look at the reported signal strength on your TV set to get a sense of the relative signal strength of each of your local channels. That will give you some insight into which channels should not be recorded.