I use a MAXRAD 800 Yagi on a torch light pole in my 1 story apt, 6' above the floor, aimed at a tower about 8 miles away (flat). It has worked great for the multipath issues that were degrading my feed and make listening to this system a challenge. Click the link in my signature to listen.
Same here on the brand but mine is the 12 element version and uses an adjustable gamma match for tuning it.
I have it on the roof of a 3 story apartment building that sits pretty compared to the surrounding buildings.
Mine is also on a cheap TV rotor that I modified with a gear and 10 turn pot for accurate direction feedback.
That mod was king of a bear to install but it ended up working fantastic. No more hoping the antenna is turning and no more hoping it is aligned with what the controller says!
Mine spins slow on really cold days but with the feedback pot installed, I can actually see if it is turning or not.
I also found a control unit for an actual CDE controller that has a nice and large illuminated directional meter in it. I think it drove a motor unit that required a 5 wire cable so its feedback circuit worked. I don't recall the actual CDE models the controller worked with. I have two of them, one has a gold colored meter and is marked with amateur markings on it and the other simply has a silver and clear meter and was sold more for the TV users back in the day.
I was able to modify my controllers so they work with the cheap TV rotors still sold out there for under $100 dollars.
This thing is dead on with the direction it tells me I'm aiming. It has to be otherwise I have an issue with the feedback pot outdoors or my gear has broken!
I eventually mounted a weather cam above my Maxrad yagi and can also use that to see which way I'm aimed.
I ended up changing the aim of the WX cam though and it is about 90 degrees off from the true antenna aim.
I did this as my primary aim of the yagi put the WX cam aiming at the woods which was useless.
As far as reducing simulcast issues, I could not be happier!
It worked fantastic for that and was one of the original reasons I even put the yagi up. The main reason was to increase signal strength from the main system I used to monitor in the 800 MHz band.
Then I found it also came in very handy for determining a sites direction when working with multi site 800 MHz trunked systems such as Ameren Electric uses here in the Midwest.
It also worked very well for that experiment once you nail down the sites expected direction. Sometimes you think you are aiming at a site only to find out the signal is actually coming in from the back side of the Maxrad yagi.
A solid panel corner reflector helped me with that problem and also did wonders in reducing or eliminating simulcast issues. The corner reflector did such a good job that I quickly found that it was wiping out signals that the yagi would still pickup from the side. The corner reflector knocked these signals too low so the 12 element yagi went back up.
Anyway, a yagi can indeed help in reducing or even eliminating simulcast or LSM problems as long as your sites towers are far enough apart that the directional properties of your yagi can work with. Yagi's with a wide beamwidth will not help as well as a yagi with a narrower beamwidth for example. All these specs should be available with or from the manufacturer. If they don't offer these specs, you are probably better off looking for a different brand as they are probably Chinese knock offs that have never seen the light of an antenna signal pattern analyzer.