Unfortunately, there's no easy or definitive answer.
The fundamental truth is that these scanners (regardless of brand) were never designed to properly receive these types of simulcast signals.
For those unfamiliar, a "simulcast" (
simultaneous broad
cast) simply means that there are multiple radio tower sites within an area that are all broadcasting the same signal on the same channels at the same time. For the users of the system, these simulcasts are great because they provide seamless coverage throughout the entire area; in this case, the entire county. It's not much different from how cell phones operate, and if anyone is familiar with the old Nextel push-to-talk network, that's basically what a trunked system is. Radios on the Rockland system can seamlessly "roam" between the 12 sites throughout the county and enjoy full coverage no matter where they are. Gone are the days where a Spring Valley cop had to be within a certain radius of the village for them to be able to communicate with 711.
So while it's good news for the users of the system in that the radios they use are designed from the start to work just fine with a simulcast, that isn't the case with scanners. Without getting into a whole technical discussion, what it essentially boils down to is that scanners use a very basic method of processing radio signals, which is not well suited for decoding simulcast signals.
Okay so why do some people report that their scanners work just fine, while others can't receive anything? A lot of it has to do with location and other factors that determine how much, or how little, signal from these 12 sites is reaching a particular scanner at any given time. With any simulcast system, there are going to be many areas where the signals from the different sites overlap each other, and this phenomenon is largely what gives the scanners so much trouble.
If you happen to be lucky enough to live very close to one of the simulcast sites, you may not have any issues at all receiving the system, because the scanner will only "hear" that one site. Because the scanner is not receiving a signal from the other sites, it has a much less hard time decoding the system. So for example, if you lived in the heart of Monsey right near the site at the Grove Street water tank, any Phase II scanner would probably work just fine in your house.
Obviously not everyone is that fortunate! For you guys in the 306/Viola Rd/Union Rd area, you're in range of at least two, possibly three, different sites. That is why the scanner is having a hard time making sense of the signal, even though the scanner's display probably shows a very strong signal. It's very frustrating, and probably doesn't make a whole lot of sense that you'd have trouble when the signal is so strong. You'd expect to have issues with a weak signal, naturally, but not the opposite.
The old saying "less is more" applies here. So we've already determined that if the scanner picks up too many of these simulcast sites at the same time, it's going to get "confused" and will just sit there doing nothing, even if it has full bars of signal strength. Obviously packing up the family and moving to a house right next to a site is not an option, so what you want to do is try to lessen the signal that gets to the scanner.
Some things to try are to enable attenuation on the scanner, which is a way to decrease the amount of signal the scanner gets hit with. Most scanners have a way to turn attenuation on, and the exact procedure varies from scanner to scanner. This may help and is an easy thing to try.
There are also some software tweaks for each scanner that might be worth trying, such as adjusting various decode settings. Some scanners have settings like "P25 Threshold" or " P25 Adjustment Mode". Sometimes they work, sometimes they don't, and there is no "one size fits all" because of the many variables involved.
Most of these settings are well beyond the scope of this thread, and detailed questions about specific scanner models should be asked in the appropriate section of the forum, not here.
You can also take a look at the Easier to Read scanner manuals at the following website for more info on your particular scanner model.
Mark's Scanners - Easier to Read Manuals