New DATV Express owner

[G4WIM]

HI guys,

just received a shiny new DATV express board and have installed the drivers ok along with Charles's DVB-S V1.05 app.

I think I have configured everything ok (capture device, callsign etc) , but the PTT button is always grayed.

Any pointers to a 'getting started guide' ?

I've also joined the yahoo group.

73 Tim

[g8vpg]

Hello Tim,
Have you selected a video format? After you have made any changes, you need to select file, save and then file, restart for them to take effect. Sometimes, I find it necessary to close the programme and restart it. It works very well though, have taken mine out portable today for the first time and worked 87km on 146.5MHz.
73 Shaun.

[G4WIM]

Hi Shaun,

ok - so rather than restarting the program under the file tab I had to completely exit the program then restart it to gain access to the PTT button, just as you said.

Doubtless I'll find other creative ways to 'break it'

73 Tim

[G4WIM]

Hi Shaun,

ok - so rather than restarting the program under the file tab I had to completely exit the program then restart it to gain access to the PTT button, just as you said.

Doubtless I'll find other creative ways to 'break it'

73 Tim

[g8gtz]

Having just helped Shaun G8VPG get his going, I've been meaning to post my experiences which may or may not help others.

Basic install is easy:

Power-up the hardware board and connect to the PC USB port. Windows should try to find a driver for the new hardware device, but cancel the windows search. The hardware should show up in the Device Manager screen as an unknown device.

Use Zadig to install the drivers - http://zadig.akeo.ie/ - Use the libusb-win32 driver select the Express board which probably will appear as "Unknown device #1" - rename it as DATV-Express using Zadig then click on install.

I used a £9 Ezcap as the av input device - don't run the CD, just plug in to a USB port and let windows find it. If it takes for ever, just cancel it - it's probably done it already.

***** Update - this appears true for Windows 8.1 and Win 10 but on Win 7 you will need to load the drivers off the CD*********

Run DVB-S V1.05 AS ADMIN - if you don't it won't tell you it hasn't saved any config changes!

It may well say it can't start the video capture device and audio capture device - ignore it for now and the program will run. Under capture select your device - in the case of the ezcap with Windows drivers it's called OEM device and select the 25 fps resolution. Select the audio capture device of your choice and then "file save as" xxx.cfg.

Now restart the program (its safest to always restart after any changes except power output level) - I found once I had configured the correct capture devices, I could press the PTT box and transmit (it was greyed out before)

The next problem was no video from the Ezcap - S video is selected by default when using the windows driver and you have no control panel so get a comp to S video adaptor or cut the s plug off and wire for comp!

*************UPdate - when using Win 7 and the driver from the CD, it appears to select composite by default ***************

Next try some video adjustments - as default it selects ultrafast delay which really is ultrafast but doesn't look too good, particularly at low SR. I found Fast was a good compromise. In the .cfg file it has generated there is a bitrate fiddle factor - this sets the maximum bit rate the video can go up to and I think it just needs to show the bar on the Tx queue bar graph. For Low SR I set it to .95 and for 4 MS to .86 but is probably very content sensitive. Finally have a play with the GOP and B frames - I found a GOP of 50 amd 3 B frames looks OK but there's loads more experimentation to do yet...

Once you've got this far save your self a load of config files for each band / SR etc and have fun.

BTW - I worked Shaun G8VPG on 146 MHz today over a 90 Km path using 125 Ks and an MER of 9 - we tried 333 Ks and failed

Hope this helps someone.

73 - Noel

[g8vpg]

Thanks for that Noel. I must try experimenting with fiddle factor you mention. File, restart works most times for me, but if it doesn't, closing the programme and restarting does.
Tim, if you're using it for RB-DATV, you need to untick the audio enable box. It always restarts with this enabled by default.
Great afternoon on the hill tops today working Noel and Dave G8GKQ.
73 Shaun.

[G4GUO]

Ez-caps need a crossbar to select the video capture input.

I have not figured out how best to add crossbar support because each capture device
uses a different crossbar and not all devices need crossbars.

The program was originally only designed to work with vMix then I was asked to add webcam support
so it is already doing more than I originally designed it to do .

Once the crossbar has chosen the correct input Windows seems to remember it.

Work around

If you have graph edit (or compatible) on your machine you can insert a crossbar into a graph
and then select the correct video input (you can then close the graph and it should remember).

If you are using vMix you can use that program to select the correct input then either use
Express with vMix or close vMix and use Express on it's own.

Hope that helps

- Charles

[G4GUO]

I have had it reported to me (and I have seen it myself) that if you use vMix to playback
a recorded video using Express as the transmitter there is stuttering on the received video.

Some quick tests show that if a conventional drive is used you do in fact get stuttering
even if you are using a very fast (4Ghz) i7.

However the stuttering goes away (at least here) if the video is streamed from a solid state drive.

In both cases there appears to be no drop outs of the transmitted QPSK signal.

vMix do advise the use of SSDs for video.

- Charles G4GUO

[g0mjw]

Hi Charles

Good to see more people using the express. I am surprised its taken so long given what it can do. How about adding an option to the capture menu that plays back from a file rather than video source?

Mike

[G4GUO]

Hi Mike,

I think that moving to the Windows platform has helped.

That would be a nice feature but I don't have the time to do it at present.
I am currently working on something non TV related which is taking
a huge amount of time.

- Charles