Yagi antenna
Before spending money on a yagi antenna, first map out the location of the towers in relation to your house. The only way a yagi will work is if you can point to a single tower without any other towers within +- 30 degrees. Also, if you have a nearby site that you don't point to then it can still be picked up by the yagi and cause problems. I have a yagi and it never helped me since there were other towers within the receive area further away. Also, with a yagi you will only hear broadcasts from that tower, so if no users affiliate with that tower then you might not hear their trunk group (I've read different opinions on whether or not this actually happens).
My first solution for simulcast was to install OP-25 on a laptop. It was difficult with the old method, but now it's pretty simple. If you have an old computer to use then the cost to do this is minimal. I also bought a Unication G4 once they offered the Phase II upgrade for free. I use OP-25 in my house and the G4 in my car. Both have perfect decodes and our local system uses a 10 site simulcast system.
I've attached a photo of the web front-end for OP-25. I bought a Dell 3179 hybrid laptop/tablet (on the Dell Outlet web site for $285) so the softkeys on the web interface work just by pressing on the screen with my finger. My only other expense was a RTL-SDR ($25) and a cheap omni-directional antenna ($10) In the display, Group Addr is the talk group number and the Source Addr is the radio ID of the unit talking.