Ahh, very good Adrian.
Sounds like some great experimentation you have going there. I believe I remember hearing in the past that the modem in FreeDV for HF does not work as well for VHF/UHF and David created the 2400A/B modes to help with that. You might have better success trying the 2400B mode if you can compile that version into your application to see if that improves some things. You would need special hardware to take advantage of the 2400A mode, but the 2400B mode is the same code but doesn’t require the magic behind the special hardware. I find it very fascinating that people like yourself are experimenting with different ways to use FreeDV, and enjoy hearing about the great efforts. Very well done, and thanks for sharing your progress with us. Walter/K5WH From: Adrian Musceac <[email protected]> Sent: Saturday, September 21, 2019 10:50 AM To: [email protected] Subject: Re: [Freetel-codec2] FreeDV SDR transmitter and receiver with GNU radio Hi Walter, Thanks for the info, I'll add the correct filters for LSB. I'm not using it for Taurus-1, this is still experimental and not ready to be deployed on anything serious. For LEO sattelite usage on FreeDV, I need to add Doppler tracking like I have for the other modes. This is a standalone GUI built on GNU radio and Qt for my own purposes and not included on any live CD called qradiolink. I test it primarily on the PlutoSDR which is VHF and above, the RTL-SDR and the LimeSDR mini. Other devices might work with it as well, like the USRP which I don't test on anymore since it always works no matter what stupid things I do with it. I'm not much of an HF user but it should work there with the right hardware. Regards, Adrian On September 21, 2019 3:14:37 PM UTC, [email protected] <mailto:[email protected]> wrote: Adria, Yes we do use FreeDV on LSB for frequencies below 10mhz. Perhaps I did not understand your setup completely, but it seems to be using UHF that your transmitting on. Are you setting this up for the Taurus-1 satellite? Ie.. UHF FM uplink and ssb codec-2 downlink? I have seen this with the LiveCD for the downlink using the Ubuntu disk, but I have not seen it being done with the setup that your using there. So it looks very interesting if it’s an alternative to that. If your only trying to use it on UHF, perhaps the 2400B mode of FreeDV may work better for you. All the best. Walter/K5WH From: Adrian Musceac <[email protected] <mailto:[email protected]> > Sent: Saturday, September 21, 2019 8:04 AM To: [email protected] <mailto:[email protected]> Subject: [Freetel-codec2] FreeDV SDR transmitter and receiver with GNU radio Hi, I got FreeDV 1600 and 700C working with the PlutoSDR and the RTL-SDR. if anybody is interested: https://www.youtube.com/watch?v=s63SSf9Yhjg Many thanks to A. Maitland Bottoms who maintains the GNU radio FreeDV module. I feel that either I'm not setting the input gain into FreeDV correctly or I'm not operating the squelch in a sensible way because I'm getting a lot of R2D2. In floating point scale of -1.0 to 1.0, what is the correct value to put into the FreeDV demodulator? With mode 700D, I'm getting a segfault in the LDPC encoder (unfortunately only have dissasembler now because I didn't install the debug symbols yet). Not sure if this is from the Debian version or not so not sure who to raise the bug with. Do people operate FreeDV on LSB below 10 MHz or is it always USB? I 'd like to know in order to set the filter correctly. I think the LimeSDR-mini should work as well but I didn't have the time to test it yet. If anybody owns other device like the HackRF or RedPitaya, perhaps they could try and see if it works properly with them. Regards, Adrian
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