Xander's Random Audio Shite

apco pROJECT 25 aUDIO qUALLITY cONCERN

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by

KanawhaCountyWX

So I’ve finally gotten my Uniden Barecat BCD996P2 digital trunking scanner working the way I want it to (I had one setting set wrong and it was decoding everything.) However, I want to gripe about the audio quallity of P25 Phase I.

West Virginia uses P25 Phase I and Phase II for a lot of state communications. Phase II is only deployed in a select few regions, and I’m fairly sure this is a recording of Phase I, but the audio quallity is terrible. I know digital is far better in terms of bandwidth use compared to analog, but P25 digital sounds horrible.

Excuse the background noise, my interface was picking up some noise.

Recorded using ProScan software connected to a Uniden BCD996P2 scanner and a FocusRite Scarlett Solo audio interface.

Comments

13 responses to “apco pROJECT 25 aUDIO qUALLITY cONCERN”

  1. Landon205 Avatar
    Landon205

    Nice. What about trunked Digitle?

    Reply
  2. KanawhaCountyWX Avatar
    KanawhaCountyWX

    Trunked analog is analog voice communications, but the channels will switch around for more effeciant use, so it’s a hybrid of analog and digital, with digital control but analog voice.

    Reply
  3. Landon205 Avatar
    Landon205

    Nice, and what is trunked analog? Also sorry for how many blog comments I have on my blog. I have over 700 of them so I’m sorry.

    Reply
  4. KanawhaCountyWX Avatar
    KanawhaCountyWX

    There’s conventional and trunked Analog, P25 Phase 1 and 2, DMR (but that’s more for amiteur use), NXDN, Tetra, D-Star, EDACS, and Fusion. Many of these are also in use by amiteur radio operators though.

    Reply
  5. Landon205 Avatar
    Landon205

    What other ones are there besides the p25 system?

    Reply
  6. KanawhaCountyWX Avatar
    KanawhaCountyWX

    Many agencies have migrated to P25 radio systems. In West Virginia, for instance, many agencies all use the WVSIRN (West Virginia Statewide Interoperability Radio Network) statewide system.

    Reply
  7. Landon205 Avatar
    Landon205

    Nice. I wonder if they also use these for fires as well?

    Reply
  8. KanawhaCountyWX Avatar
    KanawhaCountyWX

    This is, this is what most agencies in the united States migrated to over the past decade or so.

    Reply
  9. Landon205 Avatar
    Landon205

    It sounds almost like a walkey talkey to me. It sounds like they use these alot in poleace investagations.

    Reply
  10. EugeniuszPompiusz Avatar
    EugeniuszPompiusz

    Sorry for a second comment in a row: The better subjective quality score has the open-source Codec2, which serves the similar purpose mainly for HAM operators.

    Reply
  11. EugeniuszPompiusz Avatar
    EugeniuszPompiusz

    The nerdy thing about A/I/mbe codec in general is that one can set a ratio between voiced and voiceless thing. they are transmitted with clear markings and clear classification inside.

    It is a classic example of a vocoder so nothing special should be expected

    Reply
  12. KanawhaCountyWX Avatar
    KanawhaCountyWX

    P25 radio is based on the propriotary IMBE codec at a bitrate of 4.4 Kbps. Total over-air bitrate is 9.6Kbps, but that also includes signaling protocals and other such things. So makes sense that its similar in profile to the 2G CDMA codec, although that had around 14Kbps to play with, including signaling overhead.

    Reply
  13. blazy-enterprises Avatar
    blazy-enterprises

    audio quallitty reminds me of 2g CDMA

    Reply

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