Loss of local channels

Yesterday I had the DirecTV technician out to align my dish and replace a defective HR21 (gladly with a HR24).  When he turned on the other receivers my HR21 in the living room did not have local channels while the remaining receivers did.  He did twosystem resets and the local channels reappeared.  Today I turned on the living room tv and, once again, no local channels.  I did a system reset and they reappeared.  Can anyone explain this?  This will be a royal pain if I have to do it every time I want to watch local channels.