Saturday, 16 February 2013

Software Modules

This week I have been playing with a modularised version of my DATV host software
with the help of Rob M0DTS. This allows the software to be run on small embedded
processor boards like the inexpensive ARM based MK808 media player or even the
Raspberry PI. To get some idea of the size of the MK808 I have posted a picture of it
above. It is a dual core ARM A9 processor running at 1.6 GHz. I paid £32 for the
MK808 from China but they can be got for £39 from the UK. It is necessary to
replace the Android software with Ubuntu Linux, Rob used the Picuntu distribution.
As these things can be dual booted you don't loose Android.

I don't have a Digilite and the new DATV-Express hardware is not ready yet so Rob
did the actual testing of the software. He managed to transmit a 4MS/s DVB-S
DATV signal using a MK808. For input he used a PVRUSB2 and the output a
Digilite. So I think we have shown you don't need a Windows PC to transmit
DATV anymore. While I don't expect the Raspberry PI to be fast enough to work
with a Digilite it should be fast enough to work with DATV-Express as a lot of the
heavy lifting will be done inside the FPGA.

Terry G1LPS intends to use an MK808 as part of the 3.4 GHz output on GB3KM.

The code consists of a number of small modules than can either run on an
embedded processor board or as part of a DATV application running on a standard

I am thinking of converting the modules into GStreamer objects mainly because a
number of manufacturers only allow access to their GPU accelerated video engines
via GStreamer.

I still have to look at the receive side. Most of the Linux based media players are
aimed at broadcast TV and they are not particularly Amateur Radio friendly as far
a setting up is concerned. GStreamer provides video display windows that can be
embedded inside your own applications so putting together an Amateur Radio
friendly receive system should not be too difficult. I may leave this as a project
for someone else.


  1. Hi Charles Rob and Terry - quick question - are all these Android stick PCs much of a muchness or are there certain types to buy or avoid? There seems to be a wide variety of them on Amazon and eBay - bit too much choice!
    Carry on the good work. 73 Ian G8XZD

  2. Hello Ian, Well I would do a search for MK808 and check it has a dual core 1.6 GHz CPU, 1 Gb of memory and 8G onboard flash. If you get one that looks identical to the picture above you can't go wrong. Please bare in mind we are at an early stage with these devices. The version of Linux we are using is a pre-alpha release.
    Having said that these Android sticks make pretty good Internet TV boxes (for watching YouTube and the like). Rob can't seem to get more than 4Mbits/s out of his at the moment and I don't have a Digilite so I can't evaluate what is going on. Hopefully we can improve the performance.

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  4. Oh yes and it should have Android 4.1 Jelly bean on it as well (not needed for our application but it shows it is the latest device).
    There is another version the MK808B which has bluetooth and is supposed to be the same, however that is not the version we are using.

  5. Many thanks Charles. Had been looking for a while for the android sticks - have a project to do for work so hopefully I'll get them to buy me one. Was going to use a pi but this might be more appropriate.
    As for the DATV use - I think I'll let you clever people play for a while. Did you have any problems with customs on the delivery from China?

    73. Ian

  6. No, the package just appeared on the mat a couple of days ago, the postman didn't even ring the bell.