How about moving the small bedroom TV (temporarily) and connecting it to the antenna that usually goes to the living room TV? If the bedroom TV still gets poor reception, you would know that the problem is the TV; if the bedroom TV gets good reception, that would point to an issue with the cabling or connectors to the bedroom TV.
There's lots of advice and information in forums... sometimes it is correct. For example, all of my posts are made by a political appointee who got the job as a reward for contributions to my diesel bill.
2011 Jayco 28.5RLS; 2008 Chevy Duramax; Pullrite Superglide Hitch