Possible Solution:
'Weak Signal, No Program, or No Signal are usually the boxes' way of conveying the signal is too weak, nonexistant, or the channel is 'off air' such as in the dawning hours in some areas. (PBS goes off-air in some areas for example even if program guide info shows are in those time slots, that is due to a national feed but not always a time when the local affiliate is online)
It can also be due to a bad connection, or the signal to a station is distant and may require extra gain, or the antenna/cable or anything inbetween the box or antenna is bad. some RVs have permenant antennas mounted that after they age or become out of adjustment, won't pull in strong signals, or the recepticle is faulty.
The same rule can apply as rain fade. weather is one of the biggest factors in bad reception of
DTV, be it
OTA or satellite. as always in regard to weather, if the antenna is installed properly, and still has issues, you will have to wait for the condition to clear.
For a list of stations in one's particular area with all stations from easiest to pull in to hardest, go to
TV Fool - Home it's info is more detailed than that of Antennaweb.org, plus gives data on the stations' power, noise factors, and antennas likely to pull in the stations.