I think Mex and I found the problem. I just looked up the RadioShack PRO-106 and for APCO Project 25 it can only receive P25 Phase I like Mex said. OEMC is P25 Phase II and the majority of its channels use TDMA. If you want to hear channels on OEMC you'll probably have to buy a new scanner. Personally, I would recommend either the Uniden Bearcat BCD325P2, BCD436HP, or SDS100. I have a BCD436HP that I bought maybe 4 or 5 weeks ago and so far I'm really pleased with it. It does very well with the trunked systems and the reception is good. I've heard conventional analog FM channels come in with minimal static that my old BC75XLT never received at all. The speaker sounds really quiet sometimes but I could still hear it at the other side of the house. Bad news is they cost around $500 but it's worth it in my opinion.
I would recommend a Uniden SDS series scanner since the majority of the talkgroups are using the citywide simulcast site (Site-1) and depending on your location, simulcast distortion might be a problem.