EnglishFrenchSpanish

Ad


OnWorks favicon

freedv - Online in the Cloud

Run freedv in OnWorks free hosting provider over Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator

This is the command freedv that can be run in the OnWorks free hosting provider using one of our multiple free online workstations such as Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator

PROGRAM:

NAME


freedv - Digital Voice for HF

DESCRIPTION


FreeDV is a GUI application that allows any SSB radio to be used for low bit rate digital
voice.

Speech is compressed down to 1400 bit/s then modulated onto a 1100 Hz wide QPSK signal
which is sent to the Mic input of a SSB radio. On receive, the signal is received by the
SSB radio, then demodulated and decoded by FreeDV.

FreeDV was built by an international team of Radio Amateurs working together on coding,
design, user interface and testing. FreeDV 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.

New Upgrade as of March 2013


The new version 0.96 provides a 1600 bit-per-second mode that communicates at much lower
signal levels than previously. Communications should be readable down to 2 dB SNR, and
long distance contacts are reported using 1 to 2 watts power. A compatibility mode for
communication with the older 0.91 version is included.

Why FreeDV?


Amateur Radio is transitioning from analog to digital, much as it transitioned from AM to
SSB in the 1950s and 1960s. How would you feel if one or two companies owned the patents
for SSB, then forced you to use their technology, made it illegal to experiment with or
even understand the technology, and insisted you stay locked to it for the next 100
years?? That is exactly what was happening with digital voice. But now, hams are in
control of their technology again.

FreeDV is unique as it uses 100 percent Open Source Software, including the audio codec.
No secrets, nothing proprietary FreeDV represents a path for 21st century Amateur Radio
where Hams are free to experiment and innovate, rather than a future locked into a single
manufacturers closed technology.

Demo Video


Watch this video of a FreeDV QSO.

http://freedv.org/tiki-index.php?page=video

Here is what you need:

A SSB receiver or transceiver
FreeDV software
A computer with one (receive only) or two sound cards.
Cables to connect your computer to your SSB radio.

Test your Transmitter Frequency Response


When you play this 10 second 1 kHz to 2 kHz sweep .wav file(external link) through your
transmitter, the power level should remain constant. If not, look for filtering and
processing to turn off.

Connecting Your Radio


If you are lucky enough to have a "9600" input and output on your radio, this is the best
connection for every digital mode, even 1200 packet, and your audio box should be
configured for 9600 or "no pre-emphasis/de-emphasis" if it has that setting. If the
radio's configuration menu has a 1200/9600 setting, leave it permanently on 9600.

The "9600" and "1200" settings are misnamed. "9600" should really be called "direct
connection", and "1200" should be called "processed". The audio processing in your radio
does not help any digital mode.

Configuring Your Radio


Turn off as much processing as possible. In general noise blankers, DSP band limit
filtering, and narrow bandpass filters are likely to hurt rather than help. Compression,
DSP noise and carrier elimination, and voice processing are definitely wrong for Digital
modes. FreeDV's FDM modem does its own DSP, and in general this is true for other digital
programs as well. The only things that we would expect to hurt the signal are intrusion of
the opposite sideband, images of out-of-passband signals, and intermodulation distortion.
You can see the effect of different settings in the S/N display of FreeDV.

Drive your transmitter and amplifier so that it emits 10%% to 20%% of its rated power
continuously. There is a 12 dB peak-to-average power ratio in the FDM modem, and peak
clipping in your amplifier will reduce the received S/N. Modern transmitters and
amplifiers are only as linear, and only have as much headroom, as is necessary for voice
SSB. Ask manufacturers and reviewers to start rating linearity and headroom for digital
modes.

Use freedv online using onworks.net services


Free Servers & Workstations

Download Windows & Linux apps

  • 1
    AstrOrzPlayer
    AstrOrzPlayer
    AstrOrz Player is a free media player
    software, part based on WMP and VLC. The
    player is in a minimalist style, with
    more than ten theme colors, and can also
    b...
    Download AstrOrzPlayer
  • 2
    movistartv
    movistartv
    Kodi Movistar+ TV es un ADDON para XBMC/
    Kodi que permite disponer de un
    decodificador de los servicios IPTV de
    Movistar integrado en uno de los
    mediacenters ma...
    Download movistartv
  • 3
    Code::Blocks
    Code::Blocks
    Code::Blocks is a free, open-source,
    cross-platform C, C++ and Fortran IDE
    built to meet the most demanding needs
    of its users. It is designed to be very
    extens...
    Download Code::Blocks
  • 4
    Amidst
    Amidst
    Amidst or Advanced Minecraft Interface
    and Data/Structure Tracking is a tool to
    display an overview of a Minecraft
    world, without actually creating it. It
    can ...
    Download Amidst
  • 5
    MSYS2
    MSYS2
    MSYS2 is a collection of tools and
    libraries providing you with an
    easy-to-use environment for building,
    installing and running native Windows
    software. It con...
    Download MSYS2
  • 6
    libjpeg-turbo
    libjpeg-turbo
    libjpeg-turbo is a JPEG image codec
    that uses SIMD instructions (MMX, SSE2,
    NEON, AltiVec) to accelerate baseline
    JPEG compression and decompression on
    x86, x8...
    Download libjpeg-turbo
  • More »

Linux commands

  • 1
    abi-tracker
    abi-tracker
    abi-tracker - visualize ABI changes
    timeline of a C/C++ software library.
    DESCRIPTION: NAME: ABI Tracker
    (abi-tracker) Visualize ABI changes
    timeline of a C/C+...
    Run abi-tracker
  • 2
    abicheck
    abicheck
    abicheck - check application binaries
    for calls to private or evolving symbols
    in libraries and for static linking of
    some system libraries. ...
    Run abicheck
  • 3
    couriermlm
    couriermlm
    couriermlm - The Courier mailing list
    manager ...
    Run couriermlm
  • 4
    couriertcpd
    couriertcpd
    couriertcpd - the Courier mail server
    TCP server daemon ...
    Run couriertcpd
  • 5
    gbklatex
    gbklatex
    bg5latex - Use LaTeX directly on a Big5
    encodedtex file bg5pdflatex - Use
    pdfLaTeX directly on a Big5 encodedtex
    file bg5+latex - Use LaTeX directly on a
    Big5+...
    Run gbklatex
  • 6
    gbkpdflatex
    gbkpdflatex
    bg5latex - Use LaTeX directly on a Big5
    encodedtex file bg5pdflatex - Use
    pdfLaTeX directly on a Big5 encodedtex
    file bg5+latex - Use LaTeX directly on a
    Big5+...
    Run gbkpdflatex
  • More »

Ad