OP25 is a program that decodes P25 Phase 1 and Phase 2 digital radio. Some municipal areas are upgrading to P25 Phase 2 so almost gone are the days that you can track them with a police scanner since P25 is a Trunked Radio system and not just a lone frequency to monitor. The only things that do Phase 2 are hardware scanners and hardware radios and OP25 for software radios. Bear in mind Phase 2 could be encrypted and nothing you can do will decode it.
OP25 is HARD. I’m a geek and I messed with it on and off for a year or more and it whipped me more than once. Now that I have it working I find that it is REMARKABLY easy and I’m mad at all the geeks out there who never made a simple tutorial. There are tutorials out there, some good but everybody leaves out the good stuff or the stuff they took for granted.
First you need to download the latest Raspberry Pi Raspbian OS from here. Get whichever version you want but I like to get the desktop version so I can VNC into it as it makes it easier.
If you have never done this connect your Raspberry Pi to a monitor, keyboard and mouse. If you are an old salt with Linux then just run headless and SSH into your Pi.
Once you download that file UNZIP IT. UNZIP IT. The file will end with an extension of .img
Do NOT try to burn the zip file to your SD card. UNZIP IT AND GET THE .IMG FILE.
This is one of my favorite subjects. Repurposing an older computer and using it when there is no available internet connection. If you have internet that is a big plus and you can and should use it but computers are still pretty useful with no network with the addition of a couple of pieces of inexpensive hardware.
What can a computer do that isn’t hooked to the internet? Quite a lot actually. Here’s a few things you can do:
- Watch digital over the air television
- Listen to FM or AM radio
- Listen to Shortwave Radio
- Listen to Amateur Radio
- Listen to emergency service transmissions such as police, fire, weather, etc.
- Decode NOAA Weather Satellite Images
- Detect Aircraft Overhead
- Decode Digital Transmissions that are unencrypted
DSD+ is a popular Windows digital decoding program that handles various digital protocols. I’m going to install and use it with WINE on Ununtu 18.04. The example I’ll show here today is a digital trunking control channel that the local Emergency Services uses. Without DSD+ the signal will sound like this:
I set Screen Sharing up on Ubuntu 18.04 but then found out none of my clients could connect to it. After a little digging I found that in order to use VNC Viewer (or other software) from another computer that I had to disable encryption. Yeah, not ideal but I need it to work.
First go to Settings and then “Sharing”. Make sure to turn the Slider in the upper right hand corner to the ON position.