I am going to offer an alternative solution that I expect may not be supported by many others on here. Take a look at this device:
BlueTail Technlogies.
It's called the "P25RX".
It is a hybrid SDR based receiver primarily designed for reception of P25 Phase 1 and 2 trunking systems.
I can personally attest to the fact that it works very well on a large countywide simulcast 800MHz P25 Phase 2 trunking system.
Yes - you need a computer to program it to start with and to be able to see what it is listening to; however, the programming is pretty simple compared to setting up a full-on SDR system using dongles and various software solutions. The software is easy to download from the website and is easy to install and use very quickly.
Also, once programmed, you can use it without a computer unlike most SDR radios, you just won't have a display. And it works with Bluetooth car systems and portable speakers, though I haven't used that feature myself. It also has a standard analog line out analog audio jack which I use that works fine.
With a USB battery pack you could also use it "portable"; is is very small, pretty lightweight though solidly built. You would just need a bluetooth speaker or headphone for audio reception. No display, unfortunately, but the audio is VERY good!
There is an active thread about this device on RR here:
P25RX P25 Phase 1/2/DMR Receiver With Bluetooth Audio Support. It's a long thread and has a lot of discussion about the unit with the developer as he is constantly updating and improving the software and firmware according to user comments and suggestions - which is a good thing!
Initially it did not support P2 but it now does (again - long thread, if you are put off by how long that thread is just at least read the first page or so and then the last two or three pages to catch up) and does so VERY WELL!
My knowledge of radio design is not trivial and I am somewhat "picky" when it comes to RF. Suffice it to say that, since getting this device it has now become my primary 24/7 trunking system monitoring unit for my area.
That said, no, it's not perfect. I think it shines the most on 700/800MHz band trunking. It can do conventional though only using command line instructions using the console in the software (though they are fairly simple commands). It can also do analog in a similar fashion.
It also won't go lower in frequency than about 140MHz or so so it won't do Low Band VHF nor the civilian air band but your current 15X is excellent for both of those frequency ranges anyway.
It can now also handle DMR and is in the process of being able to handle NXDN; the latest test software and firmware has initial NXDN support for conventional non-trunked NXDN. I have not tested this functionality, though, myself.
The developer is very receptive to comments and suggestions for feature improvements, etc. But he is one guy and has limited time, etc. That said, it's pretty amazing how well he has done with the limitations he has to handle.
Also, though it is supposed to be able to handle trunking on VHF and up I have not tested it at those frequencies as I do not live close to any such systems. I can only vouch for 700/800 MHz trunking and some testing at some VHF conventional stuff.
For $249, unit only with back-of-set telescopic antenna and $259 for the same plus a 1/4 wave 800 MHz mag-mount "spike" antenna added I would definitely say this is a very good deal!
In my opinion, if I were you, I would hang on to that 15X you already have and use that for all things analog near you and then get this device, the P25RX, for the trunking system near you. Much cheaper than an SDS or Unication pager which are your only simulcast-friendly handling receiver-only choices. You would then have a nice well-working system for monitoring your local area at a very reasonable cost.
-Mike
