Tuning one tv knocks out reception on a second one.

We have two tv's, main one in liiving room another in a room adjacent to the living room.  When the main tv is on I can only watch local channels on the second one. If I change to any channel above 100 on the second tv (either with the guide or direct channel number entry) the main tv reception dclicks off and goes to "Searching for Satellite - 771.  It will momentarily tune in then return to the search mode.  As soon as I return to a sub-100 number channel on the second tv, the main tv returns to normal reception.  This seems to usually only occur on the weekend - am I nuts??