New Digital Voice Codecs for HF Ham Radio.....

Discussion in 'Survival Communications' started by BTPost, Apr 5, 2013.


  1. BTPost

    BTPost Old Fart Snow Monkey Moderator

    HAM RADIO SCIENCE: IMPROVED FREED VHF DIGITAL AUDIO SOFTWARE NOW
    AVAILABLE

    A new upgrade to FreeDV has been released. Amateur Radio Newsline's
    Heather Embee, KB3TZD has the details:

    --

    FreeDV is a part of a ham radio developed digital audio system that
    should eventually allow just about any SSB radio and any computer
    operating system to be teamed together. This to enable transmission and
    reception of what developers call high quality narrow-band digital
    audio for the High Frequency amateur radio bands.

    To make this happen speech is compressed and then modulated onto a 1100
    Hz wide QPSK signal which is sent to the microphone input of a SSB
    radio_On receive, the signal is demodulated and decoded by the FreeDV
    software.

    The new upgrade called version dot 96 became available on March 23rd.
    It provides a 1600 bit-per-second mode that communicates at much lower
    signal levels than previously envisioned. As such, signals should be
    readable down to a 2 dB Signal to Noise Ratio, and long-distance
    contacts have already been reported using only 1 to 2 watts power. A
    compatibility mode for communication with the older dot 91 version is
    included.

    Developers say that an executable program for Windows is presently
    available. Also that Linux and other platforms will follow shortly.

    FreeDV was brought into being by an international team of radio
    amateurs working together on coding, design, user interface and
    testing. It is open source software, released under the GNU Public
    License version 2.1. The FDMDV modem and Codec 2 Speech codec used in
    FreeDV are also open source.
     
    DKR likes this.
  2. DKR

    DKR Interesting ideas, interesting stories

    Thanks, sound like just the thing for my portable QRP rig!
     
  3. techsar

    techsar Monkey+++

    CAUTION!!! Make sure the download is free of any virus before installing. This has been an issue encountered by a couple amateurs around here...ended up having to do full system restores.
     
  4. DKR

    DKR Interesting ideas, interesting stories

    Thanks! I always scan everything before loading but its nice to know some stuff may be hiding in the code..
     
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