DATV-Express Project - February update report

[KenW6HHC]

Charles G4GUO has made good progress on a new piece of Windows software for the DATV-Express board that is called Express_DVB-S_Transmitter.
(a) The main difference from the DatvExpressServerApp is that the user does NOT have to install-or-configure utilities like GraphStudioNext to create a graph by configuring the “filters”.
(b) many video capture devices can now be used (including support for professional capture devices like the Blackmagic Decklink mini recorder or the Magewell USB3 dongles) to connect your camera.
(c) the new software will extract the video and audio streams from the capture devices and encode them in software.
(d) the ZADIG software is used to simplify the loading of drivers in Windows.


Block Diagram of typical set-up for Express_DVB-S_Transmitter software on Windows

The Express_DVB-S_Transmitter software is still in a highly “experimental stage” without any user guide yet….but has been successfully installed and used by several “early adopter” hams. The software has been now tested on Window10 and on a PIPO Windows tablet. The current build of the software can be downloaded at:
https://www.dropbox.com/s/97f5g8n9nw3bd ... r.zip?dl=0

Art WA8RMC had difficulty sending another batch of DATV-Express hardware boards to the project’s distribution center in England. Between the US Postal Service and the Royal postal office in UK and the customs people, the in route box of boards sat idle from Feb 04 until Feb 22. The team expects the new batch of boards to be in England inventory this week.

Frank DL2JFL was very kind to translate the current ODROID User Guide for the DATV Express board into the German language. This German translation is now available for from the project teams web site http://www.DATV-Express.com on the DOWNLOADS page. Frank explained that the PDF will also be available on his club webpage http://dk0gno.dnsuser.de. (sorry…but that site is only in German).

"project is set to slow speed"....de Ken W6HHC

[F1CJN_alain]

Everything is running well here with VMix as input (because I have a Logitech C525 cam and not yet a C920)
Thanks a lot for this nice version, stable and very easy to use.
Best 73's
Alain
F1CJN

[G4GUO]

Hello Alain,

C920 HD cameras are not my favourite device today. I am trying to get it to output 25 fps
and it will either let me have 30 fps or 15 fps! Looking at the Logitec website they say
their software does not support 25 fps but other software might.

Also their driver S/W won't do things that the Microsoft standard UVC driver will do.

All this to stop Max Headroom appearing on GB3SQ!
https://www.youtube.com/watch?v=z52uxxyEy0E

- Charles

[ON1AVO]

Charles,

With version 1.04 I observed the following:
- less stable, short "Not responding" error after selecting another config file
- negative TX frequency in the config file after configuring, saving and restart

Datv Express v1_04.jpg (240.04 KiB) Viewed 8508 times

[G4GUO]

Thanks for letting me know.
I have not been able to re-produce it but I am aware of a potential issue in 1.04.
(a variable that is updated by multiple threads was not being protected from simultaneous access).

I have corrected it in my current development version (which I plan to release
when I have updated the notes file).

- Charles

[F1CJN]

Hello Charles
Just for info.
The program run fine on my laptop Medion S2217
It uses the same Intel processor as Pipo, same price (150€=180€-30€ refound by Medion), but with keyboard, full 11.6 " hd 1920 screen, plus battery for 8 hours)
I am running on it Minitioune, VMix demo and DATV-Express at the same time !

73's
Alain
F1CJN

[G4GUO]

Hello Alain,

Thanks, that sounds an interesting device.

By the way I posted a slightly updated version of the software 1.05 yesterday.
There is now protection around the tx queue (I believe that is what was causing the unexplained crashes).
I also slightly changed the way it estimates the video bitrate.

https://www.dropbox.com/s/97f5g8n9nw3bd ... r.zip?dl=0

I look forward to hearing from the folks that bought an Express board to use on the activity weekend!

May your DX be long and your dropouts short

- Charles

[g8gtz]

Prompted by the availability of the Windows s/w, I've finally gone to the dark side and bought a DATV Express.

Installation was very easy - just connected up the USB cable, download and run Zadig and it works. Run the program, select audio and video device (it will show any useable devices on your system including the PInnacle DVC100 on Windows 7), save the config, restart and off you go! Excellent MER on all bands including RB-TV on 146 MHz.

But be warned, depending on where you install the program you may have to run it as admin to be able to save the cfg file - it doesn't warn you it's not saved and won't run on restart because the A/V devices are not saved! If you don't change the file location suggested by the installer (as I did) you won't have the problem!

One question - does it have a Tx key line out to turn on amplifiers / change over relays etc when the software PTT button is on? I found J4 pin2 but I think it is DATV Express tx disable...

Hope to have it on air during the BATC activity weekend in 3 days time

73

Noel

[G4GUO]

Hi Noel,

Yes J4_2 is now PTT out. I had a quick look at the Verilog code.

- Charles

[g8vpg]

Charles,
You asked for feedback from the new users of DATV Express and the windows software. I loaded the driver using Zadig and this worked well on two Windows 8.1 computers. I have installed the latest version of the software which installed easily once I told Windows and Norton to allow it - big red warnings!! I now have it running well on 1249MHz and 146.5MHz 333ks/s with full scale MER. I have used a generic webcam and Vmix as inputs. It took me a while to puzzle out video formats and frame rates; the TX queue kept overflowing until I selected the as input option. However, once some notes are published, this won't be a problem for future users. When I first used it, I did produce a complete PC freeze, I think because I repeatedly pressed PTT, forgetting to save and reset first. Since then, it has run well. Overall, I am very pleased and thank you for your efforts.
73 Shaun G8VPG.