Posts by SWL - markro92

Version 2.0.19

Download: http://v.1337team.tk/dvb-s_gui_amsat.zip

Changelog:

• Fixed frequency slider input not working above 2147MHz.
• Fixed off-by-one error in SDT (Service Descriptor Table) parsing code.

Edit: The next update will probably be missing the dropdown box for the rolloff factor,

further simplifying the UI.

The rolloff factor for DVB-S1 is always 0.35.

For DVB-S2 it's transmittd inside the BBHEADER after successful LDPC decoding.

Second thing is interpolation before decimation, which means i can also get rid of the M&M Timing estimator, only using Gardner.

Number three on the roadmap is changing the demapper, so that it's using a lookup table for determining the likelihood ratio for every bit of the constellation, which will be fed to the LDPC decoder. Currently i'm doing that by rotating the constellation and using I and Q values directly.

The new approach will also simplify 16APSK and 32APSK demodulation which is hopefully working until then. I also started working on a hardware solution. I'm currently doing a prototype PCB layout which can be plugged onto an existing FPGA board (Numato Neso with an Artix7 FPGA). I'm planning to use a MAX2121 as mixer IC. I'll open a new forum thread for that when i have more to show.

Marcel

Hi, i've read your posts and i probably already know the solution for the problem. I've used signed 32-bit integers somewhere in my code. So the maximum value should be 2^31 - 1, which is 2147483647 Hz, which corresponds to about 2147MHz. I'll quickly release another version with a possible fix.

Ok good to hear. I'll wait for reports of the others.

Hi, i've updated the archive, build date is 18:40:18. Can someone tell me if the networking problem still persists? I'll try to debug this. It's kinda hard, because i never had problems. Hopefully we can narrow down the problem.

DD4YR: did you download the file correctly? make sure you didn't extract an old archive. The Release notes and the titlebar need to show version 2.0.18

SWL-ALAIN: i checked the download but it seems to be fine. Try deleting your browser cache. Maybe you extracted an old archive.

The problem is as usual that for me the network stuff works. UDP really shouldn't be a problem. I'll start investigating

Is someone available for a teamviewer session?

Does recording MPEGTS to file work?

DB8TF: For TCP you need to use the whole URL: tcp://127.0.0.1:8888.

I just changed the config.ini to be backwards-compatible and uploaded a new file.

Version 2.0.18

Download: http://v.1337team.tk/dvb-s_gui_amsat.zip

Changelog:

• Fixed crash when changing the samplerate for LimeSDRDevice class.
• Added TCP server for MPEGTS output.
• Changed the TX button to a dropdown list where UDP or TCP mode can be selected.
• Added new config options "ip_out_addr", "ip_out_port" and "ip_out_mode"
• The MPEGTS TEI bit (Transport error indicator) is now set when LDPC decoding fails.
• Added parser for MPEGTS SDT Tables. Program names are be shown inside the FFT Plot.
• The Filter drowdown box for the IQ plot is working now.
• Removed the checkbox for enabling/disabling symbol interpolation. No need to turn it off.

Marcel

Hi, tomorrow i'll release a new version with a few experimental features. Those are:

TCP Server for MPEGTS output and a parser for MPEGTS SDT tables. Station names (and callsigns) will be shown inside the FFT plot.

G0MJW: added your feature request.

There is a new config option "iio_net_contexts" which allows specifying hosts as a space-separated list.

Build date is Jun 14 2020 14:35:37

G0MJW: do you have any kind of info how the pluto transmits samples via the network? TCP? UDP? some kind of header? Or are you using Gnuradio sink blocks for that? I could add a generic TCP/UDP input device with some kind of settings dialog if it helps.

G0MJW: only USB is supported for now

ok, i'll upload a new file in about 5min.

edit: Done! Build date is 12.06.2020 20:35:33

@GOMJW: normally i like the idea of giving the users maximum freedom when it comes to settings, but the majority of SDRs have fixed limits set by the manufacturer. Exceeding those limits normally doesn't do anything, it simply won't work. Of course the PlutoSDR is an exception here. I need min/max values for the UI sliders. But i could make those values adjustable by editing the device.ini. I think that's what i'll do.

Ok i've found the problem (forgot to change int8_t types to int16_t inside the sdrplay device class)

I didn'tchange the version number, but i've updated the download. The build date should be Jun 7 2020 16:09:27

In my case maximum gain works well, and increasing the FFT Intensity a bit for the looks.

DB8TF: Wenn du M&M TED nutzt (z.B. wegen RTLSDR und niedriger Bandbreite) dann musst du bei TIming Recovery niedriger gehen mit den Gain werten. z.B. 1/256. Damping kann sogar ganz nach links. Ich muss die Standardwerte mal anpassen.

Hi, i updated the config file just now. I totally forgot about this. Thanks for telling me

Ok i fixed the download, somehow i managed to screw this up

A dualcore is a little bit of a challenge, but for low symbolrates it's fine.

the Es'Hail 2 Beacon should work with it

Version 2.0.17

Download: http://v.1337team.tk/dvb-s_gui_amsat.zip

Changelog:

• Added 16bit sample input path for devices that support it
• Improved automatic gain control for incoming samples
• Lowered minimum frequency to 50MHz for users of modified plutosdr firmware (user request)

Sorry for not working a lot on this project right now, but i'll atleast release what has been done for now.

Notes: This release contains some none-working features, these are the Decision directed equalizer,

And the dropdown box for filtering samples in the IQ plot. AGC stuff changed the timing recovery gain settings, you should use lower values now.

@G4XAT: please tell me if the lower frequency limit for the PlutoSDR works for you. I don't have the possibilits to test it at the moment.

Marcel

Hi, this has nothing to do with yor CPU, i'm having the same problem. The PlutoSDR uses libiio, which is a piece of software by Analog Devices handling all the USB stuff. but the problem is, that i need to poll the data, which means, that i need to ask it for a new chunk of samples. If i don't manage to do it frequently enough, there are lost samples. And that's the worst thing that can happen for a DVB-S demodulator...

There are many reasons for this problem. It can be the operating system not scheduling the thread often enough which does the polling. That's the case on high CPU load, or if there are peaks in CPU usage. Of course, this is an important problem, which i need to find a solution for. A temporary solution could be using lower samplerates. That improves things a little, but it doesn't fix the problem. I recommend other SDRs at the moment until i come up with a solution. As far as i know, the PlutoSDR and LimeSDR have this problem. I'll keep you posted on this.