DATV-Express Project

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G4GUO
Posts: 530
Joined: Tue Feb 16, 2010 12:51 pm

Re: DATV-Express Project

Post by G4GUO » Sat Jun 09, 2018 9:17 am

I tried and it seemed OK here with Minitioune but others have said it is no better.
The PCR clock is now locked to the frame rate of the video however
my analysis software says the PCR clock is not being sent often enough.
The audio free runs but when the error between it and the video
exceeds a certain amount the audio clock is adjusted so it matches
the video clock.

I use vMix myself as that conditions the video source to have the right
framerate and image size which makes Expresses job much easier as
it doesn't have to cope with non standard webcam video formats.

- Charles

g0mjw
Posts: 523
Joined: Sat Sep 20, 2014 9:15 am

Re: DATV-Express Project

Post by g0mjw » Sat Jun 09, 2018 10:18 am

So does that mean it is best to send it a particular resolution and frame rate - and if so what are you using?

Mike

G4GUO
Posts: 530
Joined: Tue Feb 16, 2010 12:51 pm

Re: DATV-Express Project

Post by G4GUO » Sat Jun 09, 2018 11:00 am

Ideally 25 frames per sec but webcams use 30 fps so I use vMix to do the conversion.
For Express set the onair format to input format as most device drivers can't do
rate conversion and Express asks the device to do the rate conversion.

As for picture dimensions that doesn't matter too much as it depends on what the receiver can do.


- C

KenW6HHC
Posts: 269
Joined: Mon Jun 01, 2009 4:20 pm

Re: DATV-Express Project

Post by KenW6HHC » Sun Jul 01, 2018 2:12 pm

Art WA8RMC reported most sales of MiniTiouner-Express in June, were sold outside the USA. The latest inventory in England for sales-to-EU is down to three units. Art confirmed he can purchase an order for another batch of Serit NIM tuners (100 units).

Ken W6HHC finished testing the LimeSDR-mini unit with v1.25LP7. Everything worked well. Ken then switched to testing v1.25LP7 on the DATV-Express board focusing on the correction of the time-stamp code issue that had allowed the audio to quit in DVB-S protocol mode after a short time (less than 60 seconds) on v1.25 software release. Ken also confirmed that RB-DATV (Reduced Bandwidth works well with on the DATV-Express board with this software and the new software. Ken did confirm one bug with the experimental v1.25LP7 software, where the transmitted RF output power-level on the DATV-Express board always starts at 100% when the PTT is pushed (regardless of the setting shown on the display or .cfg file). It is easy to work around the 100% RF Power issue…but, it is a bug. Art ran into an old problem with MiniTiouner-Express receiver while testing v1.25LP7 on the DATV-Express board. When loading LAV decoder filters for MiniTioune software, Art’s main Win7 64-bit notebook usually decides to choose Microsoft DVD Video Decode filter (not LAV filters). The result is that his video displayed by MiniTioune-Express is very jerky with a frame rate of maybe 1 FPS (or less). Ken and Art are still working through the somewhat tedious procedure to assure that correct LAV filters are successfully loaded on Art’s notebook

Image
Screen-capture of v1.25LP7 software driving a DATV-Express board with DVB-S protocol. The audio was perfect.

Charles G4GUO reported that he is very busy on many projects. He reports that that most of his testing of v1.25LP7 software so far was limited to testing the LimeSDR exciter board. It has become very time consuming to carefully test all of the supported exciter boards:
• DATV-Express
• LimeSDR
• LimeSDR-mini
• PLUTO
The next available experimental software will fix the DATV-Express 100% RF Power-out bug and another issue if you are using B frames, as soon as he tests the software on Pluto. Charles plans to make available an updated experimental package for v1.25LP that corrects some bugs within a week

Project Speed is set to moderate….de Ken W6HHC
Last edited by KenW6HHC on Sat Jul 14, 2018 12:13 pm, edited 1 time in total.

KenW6HHC
Posts: 269
Joined: Mon Jun 01, 2009 4:20 pm

Re: DATV-Express Project

Post by KenW6HHC » Fri Jul 13, 2018 7:28 pm

Just a quick note to say that the experimental software release of v1.25LP9 (on Windows) is now available to DOWNLOAD (free) from the DATV-Express web site at www.DATV-Express.com
v1.25LP9 now supports four different DATV exciter boarda:
• DATV-Express board
• LimeSDR board
• LimeSDR-mini board
• PLUTO board

While the v1.25LP9 needs more testing by users…it seems stable with all four board types and has no obvious bugs. This is much better than the V1.25 software that had been around for about one year. Read the NOTES_v1.25LP9 text file for a description of recent fixes. Give it a try. Let us know of any bugs that you find.

73…de Ken W6HHC
Last edited by KenW6HHC on Mon Jul 23, 2018 2:39 pm, edited 1 time in total.

VK5YYY
Posts: 58
Joined: Sun Sep 27, 2015 1:47 am

Re: DATV-Express Project

Post by VK5YYY » Sat Jul 14, 2018 1:20 pm

Hi Ken/Charles,
I fired up my Pluto today, didn't take to long to download all the drivers etc. I've seen some pictures, so far so good
My first comment is I can't get the frequency off 1300mhz, no matter what I set it to it remains at 1300mhz
I'm trying to get above 3Msym but the best so far is 3.2ish, is that about all I can expect?
Anyway, well done chaps
Cheers Roger VK5YYY

G4GUO
Posts: 530
Joined: Tue Feb 16, 2010 12:51 pm

Re: DATV-Express Project

Post by G4GUO » Sat Jul 14, 2018 1:35 pm

Yes you are limited to around 2 MS/s for the Pluto. It is a limitation of the Pluto I am afraid.
The frequency is entered in Hz and should cover the entire range.

- Charles

VK5YYY
Posts: 58
Joined: Sun Sep 27, 2015 1:47 am

Re: DATV-Express Project

Post by VK5YYY » Sat Jul 14, 2018 1:44 pm

Hi Charles,
Well I'll try Lime mini next
The Hz thing fixed it
Thanks for the speedy response
Cheers Roger

VK5YYY
Posts: 58
Joined: Sun Sep 27, 2015 1:47 am

Re: DATV-Express Project

Post by VK5YYY » Sun Jul 15, 2018 5:15 am

Hi Chaps

Tried Lime Mini today, again easy to down load drivers
Tx first time (that was a pleasant surprise)
Msym ok at 2Msym but 3Msym no good, I would say Pluto did better at higher Msym than Lime Mini
Could it have something to do with my old PC

Every setting change upon hitting TX, it would forget Lime was there
Closed program which then restarted express capture server
Lime mini not found 1005, had to close the program again
Unplug Lime mini
Restart then was fine

My rating is 8/10 I will try to obey the speed limits, but I want to go faster (like driving Mum's Oxford Morris for the first time)
Both units good bang for buck and the software is really getting there for Lime and Pluto
Any chance we will see RPi running the show one day.....Portsdown Express maybe?

Cheers Roger

G4GUO
Posts: 530
Joined: Tue Feb 16, 2010 12:51 pm

Re: DATV-Express Project

Post by G4GUO » Sun Jul 15, 2018 6:58 am

I believe Dave G8GKQ plans to add Lime support to Portsdown but I will let him confirm or deny that.

Probably your PC as I can transmit 7 MHz DVB-T on my Lime which is the equivalent of 8 MS/s on
DVB-S (as far as USB3 load is concerned).

The problem is there is too many "other peoples" software in the chain.

- Charles

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