Welcome to the new FlexRadio Community! Please review the new Community Rules and other important new Community information on the Message Board.
If you are having a problem, please refer to the product documentation or check the Help Center for known solutions.
Need technical support from FlexRadio? It's as simple as Creating a HelpDesk ticket.

FreeDV question ...

Gary L. Robinson
Gary L. Robinson Member ✭✭
edited February 2020 in FLEX-6000 Signature Series
Many digital modes are sideband dependent - many are not dependent on sideband.  If one station is running PSK31 in lower sideband and another is running the same mode in upper sideband there is no problem.  Both will be able to decode the data sent.  If they were both running Olivia mode but on different sidebands neither would be able to decode each other.

So, my question is ... Is FreeDV, or to be exact - the SmartSDR FreeDV waveform,  sideband dependent as far as decoding the voice data?  If someone is running the actual FreeDV software on his NON Flex rig - will it even run in both sidebands?  And, assuming it is running the same codec and the person who is running it is in lower sideband -- can the SmartSDR waveform (which appears to be upper sideband only) decode him?


  • Mark Erbaugh
    Mark Erbaugh Member ✭✭
    edited February 2020
    FreeDV is sideband dependent. A station listening in USB cannot decode a station transmitting in LSB. The "standard" for FreeDV has become LSB below 10 MHz. Since the Flex Waveform only works in USB, it cannot decode standard transmissions below 10 MHz.
  • Gary L. Robinson
    Gary L. Robinson Member ✭✭
    edited March 2017
    Thanks Mark!  Appreciate the info even though it is a big bummer hihi  I think I will see if I can get the latest release of FreeDV program to work with my 6300 and just take the wave form version out for now.

    --Gary WB8ROL
  • David
    David Member ✭✭
    edited March 2017
    Flex provide the current version of the FreeDV waveform and has release it to the community to maintain. Hopefully someone is able to pick it up and make the need updates along with adding LSB support. In the meantime the native FreeDV will just like you would use FLdigi.
  • hans weijers
    hans weijers Member
    edited March 2017
    As FreeDV is not a digital but a voice mode, FDV must follow the sideband conventions on the amateur bands, So LSB under 10Mhz and USB above as said before. Keep in mind that the current FreeDV waveform from Flexradio still has problems with spikes, due to timing problems in the 6000 series, which can end up with damaging, even destroying, a LDMOS amplifier. Just get the latest FDV program at freedv.org (V1.2), install it on your Flex PC, configure the (virtual) audio and PTT settings, use DIGI-L or DIGI-U and be able to decode and transmit in FDV mode. A bonus is that you will not only be able to use the 1600 mode but also 700B, 700C and 800XA mode. We in The Netherlands use this method with great succes.
    73, Hans PA0HWB
  • Chris
    Chris Member ✭✭

    except for reasons of intransigence or habitual tradition, there is no reason to use LSB with a mode using a digital transmission on any band. since the great majority of digital transmissions are USB, and government and military long ago transitioned to USB below 10 MHz, so too should FDV use USB on all HFs bands.

    my 0.02 USD.

    = 73 =

Leave a Comment

Rich Text Editor. To edit a paragraph's style, hit tab to get to the paragraph menu. From there you will be able to pick one style. Nothing defaults to paragraph. An inline formatting menu will show up when you select text. Hit tab to get into that menu. Some elements, such as rich link embeds, images, loading indicators, and error messages may get inserted into the editor. You may navigate to these using the arrow keys inside of the editor and delete them with the delete or backspace key.