Voice very garbled, you can make out an occasional word. Ordered a SDR Dongle that picks up P25 digital signals. And yet, I still haven't found a display that trounces last year's Alienware 34 QD-OLED. Older analog systems occasionally used rudimentary scrambling that could be cracked with decoder kits or even monitored by some people that could make it out audibly. I'm not going to pretend it's perfect -- I've complained about its insistent burn-in prompts in the past, for example. There is a sync pattern in the document which has 48 bits (or equivalently 24 symbols) by which we can correlate to find the sync signal. I'll look into the GNU radio angle. Thought I would share a article on decoding p25 encryption Security Researchers Crack APCO P25 Encryption - Slashdot . $40 RTL-SDR trunked scanner. If you do not see any coordinates in the DSD+ event log when an LRRP event occurs this may be the case. It isnt an internal or external command. DSD will start attempting to decode immediately. It's a lot harder to set up, but then, I came across these dual monitors that were initially launched on Kickstarter. talkvoice ----> mic ---> Encryption PCB --->transmitter -------->AIR <------- Reciever ----> Decryption PCB --> speaker ---> Ear ? It can save the compressed digital audio bits to "mbe" data files (.imb and .amb extensions) and play back those saved files. VAC is my default device. today I set just this way again and no decoded P25 audio to speakers. You might be connected to a trunked frequency. To stop DSD, simply press ctrl + c at the command prompt while it is running. Can anyone explain it to me step by step? OP25. I have ERR3 on each line, and no sound. Also, try VBCable. Any settings I should look at? This is useful for tracking a fleet of vehicles for instance. That said, to run the latest version of DSD+ all you really need to do is double click on the .exe file. All these DSD+ files should be uploaded to GITHUB. Tnx. I can usually improve my decode with small changes in antenna position and orientation. Thanks again Kevin. How does this work in Estonia? Any ideas on fixing this? It's discussed in this forum. DSD+ claims to have improved decoding and audio quality capabilities. I just talked to the dealer who sold the EMS Service the radios and they are encrypted. CKR does not go over the air. To show a screen shot use an image service like http://imgur.com/, then link to it here, or attach it in a post in the forum. i dont understand. i have downloaded dsd+ opened the programme all the windows appear but not sure where to go from here. Most police departments is the USA have now upgraded or are in the process of upgrading their radio systems to P25 Phase 2 digital radio. One RTL-SDR/USB Plus, I think youre probably getting the audio spectrum in the waterfall, and not the RF spectrum. Then youll need a second dongle for intercepting voice traffic. or my problem is in my setup configuration? After almost 2 years of not having time for this I am glad to say i am back at it again. Im not sure whats up with this, but I dont get any audio. (I tell ya, it aint easy being stupid!). DES uses a 56-bit encryption key and AES uses a 256-bit encryption key. As stated above, you are looking at Hex vs decimal. . Hence as it the default in the playback no sound comes from the speaker!!! Ive asked around a lot as well but have always gotten a no it cant happen answer everywhere. And even in situation one, most radios is locked / protected from reading and changing the encryption keys & channel info, so no luck there. A lot of people confuse this as being encryption. When I put Key ID 60 in the radio, it shows the same in DSD+. Now I know my sound settings are ok. One other question. Thank you for your time. salut cest normal car sur un canal il peut yavoir plusieurs conversation. What type of signal are you attempting to decoding? Im really thrilled. Also found voice meter (does the same thing). DSDPlus has no more options -xr -xR ? While this tutorial is aimed at the RTL-SDR, other software radios such as the Funcube dongle, Airspy, HackRF and BladeRF will also work. Police, fire, ambu is mostly crypted, but enoug clear signals to receive. ??? Still nothing. Digital radio voice communications are becoming more commonly used in the radio spectrum. (DSDPlus