FreeDV question ...

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  • Updated 3 years ago
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?
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Gary L. Robinson

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Posted 3 years ago

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Mark Erbaugh

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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.
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Gary L. Robinson

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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
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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.
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hans weijers

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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 (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