DATV-Express Project

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kd2hns
Posts: 5
Joined: Tue May 01, 2018 10:43 pm

Re: DATV-Express Project

Post by kd2hns » Fri Jun 01, 2018 7:43 pm

Charles

I upgraded the express software to v1.25p6 for my pluto on my windows 10 computer with settings (1249mhz dvb-s2 at 2200000 SR, FEC 2/3,8PSK using h264).
The MER went from 19db to 36db the Timing Lock went for 60% to 98%, RF went up by 10db, Constellation is very sharp and better too it seems so far stable. Good work on the beta upgrade. Now on my windows 7 computer v1.25p6 wouldn't start and gave a hex error. I downgraded back to v1.25p4 and it worked again. Keep up the good work and thanks for a great program.

Chuck

G4GUO
Posts: 629
Joined: Tue Feb 16, 2010 12:51 pm

Re: DATV-Express Project

Post by G4GUO » Fri Jun 01, 2018 9:49 pm

You might need to install a Microsoft re-distributable but the error message should have told you that (I re-compiled everything with a more up to date version of Visual Studio). So it is probably something else. I think I have had it running on Windows 7. I will try and make a new version that has
Lime support available this weekend. I was supposed to do it last week but I got diverted onto something else.

- Charles

dk9sas
Posts: 3
Joined: Sat Jun 02, 2018 7:57 pm

Re: DATV-Express Project

Post by dk9sas » Sat Jun 02, 2018 8:31 pm

Charles, I noticed that version 1.25p6 brought me an error about a missing audio device. When I selected the right device in Capture -> Audio and pressed "Ok" it didn't save the new value to the datvexpress.cfg file: The [CAPTURE AUDIODEVICE] entry wasn't updated and after a restart the same error came up. Altering the config file by hand worked however.
Could you maybe please leave a note in the readme where you'd like bugs reported? I found your github repo, but it seems a bit out of date/and the issues there are marked as open also for a while - are you still watching this, too?

Many thanks for your great effort in this field :)

73 Sascha

G4GUO
Posts: 629
Joined: Tue Feb 16, 2010 12:51 pm

Re: DATV-Express Project

Post by G4GUO » Sun Jun 03, 2018 11:45 am

Hi Sascha,

Best place would be to email the bug to support@datv-express.com

I have managed to re-create the issue. It seems that if there is no
valid hardware found it won't automatically save the information.

The work around is to use file->save then the configuration file is
correctly saved. This bug affects all the configuration information not
just the sound.

As far as Github is concerned, no I have not been updating it. I just
released the code so that other people could use parts of it in their own
projects. My development environment pre-dates my use of Github
so I have to manually update everything.

I read yesterday that Microsoft are talking about buying Github.

- Charles

G4GUO
Posts: 629
Joined: Tue Feb 16, 2010 12:51 pm

Re: DATV-Express Project

Post by G4GUO » Mon Jun 04, 2018 7:20 am

Sascha,

This may have fixed it, it also has better LimeSDR support (Lime must have latest firmware loaded).

https://www.dropbox.com/s/7bls8zjsueg17 ... 7.zip?dl=0

- Charles

on4bhm
Posts: 79
Joined: Mon Oct 24, 2011 5:52 pm

Re: DATV-Express Project

Post by on4bhm » Thu Jun 07, 2018 8:28 am

Just to say i was very pleased with the latest version for lime.

tested dvb-s in 4167 KSym/s in mpeg2 to on0snw repeater
both with webcam and usb capture dongle
worked fine.
made a 'travel' with camera and usb capture dongle.... not all frames were there... seemed more like 5fps.
A still video was ok.
Didn't had this with build in webcam.
(10% cpu on i7 laptop of 4 years old)

tested dvb-s2 in 4167Ksym in mpeg4 to local repeater
both with webcam (1280) and hd usb capture device.
Also here, i saw frames getting dropped while doing a 'travel' with the camera and the usb HD capture device.
(25% cpu)

this still has to be investigated.
maybe if a throw in vmix, it will be better....
to be tested.

73's
on4bhm

G4GUO
Posts: 629
Joined: Tue Feb 16, 2010 12:51 pm

Re: DATV-Express Project

Post by G4GUO » Thu Jun 07, 2018 8:57 am

I must admit I usually pipe everything through vMix as that does a pretty good job of
cleaning up the video into something that looks 'broadcast standard'. I also do most of my
testing using a looped video (saves waving my arms about all the time).

I have noticed the MER degrades when using 16APSK/32APSK which appears down to
the magnitude of the preamble symbols compared to the payload symbols. I have a
fix for this but I don't understand why I need the fix. I have read the standard
multiple times and I can't see where the different magnitudes come from. I am going
to get my calculator out and work through the maths again this morning.

Thanks for the feedback

- Charles

on4bhm
Posts: 79
Joined: Mon Oct 24, 2011 5:52 pm

Re: DATV-Express Project

Post by on4bhm » Thu Jun 07, 2018 9:33 am

Are there any cheap commercial recievers available for 16APSK or 32APSK?

I don't think i have tandbergs who can do it.... have to check...

73's
on4bhm

G4GUO
Posts: 629
Joined: Tue Feb 16, 2010 12:51 pm

Re: DATV-Express Project

Post by G4GUO » Sat Jun 09, 2018 8:28 am

https://www.dropbox.com/s/lnxqhx88qmivw ... 8.zip?dl=0

improved the 16apsk and 32apsk constellation, only tested with LimeMini

The DVB-S2 spec has two permitted versions of these constellations, the original software
had the simpler to implement version (outer constellation ring == 1). However it seems the
Serit tuners (and most others) use the other version (average symbol energy E == 1).
So while my original code technically was not at fault the new version should work better.

- Charles

g0mjw
Posts: 956
Joined: Sat Sep 20, 2014 9:15 am

Re: DATV-Express Project

Post by g0mjw » Sat Jun 09, 2018 8:47 am

Great, I will have a go. Did you do anything to improve the TS encoding recently?

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