Originally Posted by ausscan
Our county fire department is moving towards a P25 single frequency dispatch system and I was wondering if any one has successfully setup a USB SDR using SDR Sharp and piped it into a P25 decoder with success on Windows 7? How did you achieve this outcome and what obstacles did you face along the way?
I've used a Funcube Dongle Pro (the original, not the +) on Windows 7 64-bit.
Dongle --> SDRSharp --> VAC (Virtual Audio cable) --> [DSD | DMRDECODE | Unitrunker]
So basically, in SDR Sharp I set the input to my Funcube Dongle and set the output to "Virtual Audio Cable Line 1". In my Recording Devices I set Virtual Audio Cable Line 1 as the Default Recording Device. In my Playback Devices I set my speakers as my Default Playback Device.
With the Default Recording and Playback Devices set properly, then when DSD is ran it knows to get its input from the VAC output and it knows to send the decoded audio to my speakers.
DSD [in Windows] requires that the Default Recording and Playback devices be set to the devices that DSD will be getting its raw audio from and where it will be sending the decoded audio to.
I don't know about other SDR dongles, but for the Funcube, you want to set the audio level on the Funcube Dongle Recording Device to 1 or 2, no greater. Otherwise, you'll end up with a lower SNR.
I don't just listen to P25, and in fact most of the time I don't since I have a digital scanner. But from time to time [like tonight, with some enhanced propagation] I'm listening to some conventional P25 on 450 Mhz with the dongle because I already had it connected.