[Hackrf-dev] DVB-T and DVB-T2

Craig Barber radiocraig28 at gmail.com
Sun Jul 5 08:11:19 EDT 2015


The good news is I got it working, sort of, using channel_mhz = 8 - however
the picture and audio judders really badly, and basically plays back really
slow! I don't have a stream of UUUUUUUUUUU appearing in my console window,
so can't be buffer underruns, any ideas Simon?

On Sun, Jul 5, 2015 at 12:30 PM, Craig Barber <radiocraig28 at gmail.com>
wrote:

> Hi Simon,
>
> I've tried your script today with my test TV but see no signal whatsoever
> on the TV although the hackrf is definitely transmitting. I've also tried
> with a pre-recoded mpeg2 file from avconv but no luck.
>
> Any suggestions?
>
> Craig
>
> On Tue, Jun 30, 2015 at 10:57 PM, Simon Kennedy <simon at thekennedys.info>
> wrote:
>
>> I feel slightly embarrassed as I subscribed to this list using an email
>> address that is redirected to my main email, so consequently replies sent
>> from my main email address were not coming from the correct address. Hence,
>> none of the replies I posted have been seen on the list. Oops!
>>
>> Here is my reply about this thread:
>>
>> Hi Craig,
>>
>> Check out Clayton's web page (who created the sdr-examples you refer to)
>> here <http://www.irrational.net/2014/03/02/digital-atv/>
>>
>> I amended his BladeRF script and I have put my HackRF version here
>> <https://www.dropbox.com/s/bdnzoa0kn01dfav/dvbt-hackrf_tx_sk.py?dl=0> for
>> download
>> My version transmits DVB-T on the lowest Freeview channel in the UK at
>> 474MHz (obviously only while using a dummy load). I successfully received
>> the transmission of my webcam image this way using an RTL-SDR dongle.
>>
>> The command I used was very heavily influenced (ok, basically copied)
>> from Clayton's examples:
>> avconv -f alsa -i hw:0,0 -f video4linux2 -s 640x480 -i /dev/video0 -vf
>> drawtext=fontfile=/usr/share/fonts/truetype/freefont/FreeMonoBold.ttf:text="TEST
>> ":x=440:y=420:fontsize=48:fontcolor=white at 0.6:box=1:boxcolor=black at 0.4
>> -vcodec mpeg2video -r 60 -b 2000000 -acodec mp2 -ar 48000 -ab 48000 -ac 2
>> -mpegts_transport_stream_id 1025 -mpegts_service_id 1 -mpegts_pmt_start_pid
>> 4096 -mpegts_start_pid 400 -f mpegts -y in.fifo
>>
>> I used a standard web cam to capture the image, sent the output to a fifo
>> file (in.fifo) and consumed the output through the python program with the
>> command:
>> ./dvbt_hackrf_tx_sk.py in.fifo
>>
>> The fifo file can be created using the command mkfifo in.fifo
>>
>> Run the avconv command and the python program in the same directory as
>> you created the fifo file in.
>>
>> I have also transmitted DVB-S which I have documented on my blog here
>> <http://photohamrad.blogspot.co.uk/2015/06/transmitting-video-with-hackrf-blue.html>
>>
>> Simon.
>>
>>
>> On 30 June 2015 at 17:35, Simon Kennedy <simon at thekennedys.info> wrote:
>>
>>> Can you tell us the command you used to get this error please.
>>> I remember that I got a smilar error but cannot look up how I solved it
>>> until I get home in a couple of hours.
>>> The key point is that the program is trying to open a UDP port to
>>> receive the data and error relates to the asignment of the argument you
>>> supply to the program to the variable 'port' in the program.
>>>
>>> Simon.
>>>
>>> On 30 June 2015 at 16:49, Craig Barber <radiocraig28 at gmail.com> wrote:
>>>
>>>> Here's the error I get:
>>>>
>>>> Traceback (most recent call last):
>>>>   File "./dvbt-hackrf.py", line 123, in <module>
>>>>     main(sys.argv[1:])
>>>>   File "./dvbt-hackrf.py", line 31, in main
>>>>     port    = int(args[0])
>>>> ValueError: invalid literal for int() with base 10: 'testdvbt'
>>>>
>>>>
>>>>
>>>
>>
>> _______________________________________________
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>> HackRF-dev at greatscottgadgets.com
>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>>
>>
>
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