You now appear to have two issues. The newest issue is easiest to explain. When you have an antenna attached and locals scanned in, if one that you were watching, or are recording loses the signal, the receiver thinks the satellite lost the signal, and that is what you are seeing. A way to help make sure that does not happen if you have a weak OTA station, is to go to a satellite channel, after it comes on, go to another satellite channel. Meaning that way, the last chanel you were on was not an OTA channel.
The first problem could be a problem with the antenna, possibly a grounding issue? Do you have another antenna to try, using a different coax, even an indoor one, that you can try just to see if it at least lets the receiver scan for locals? (Or also try a different coax with the antenna you are now using?) If you can get at least on local with that antenna see how the receiver works with it. If everything seems to work, it very possibly is the antenna/wiring you are now using.