DVB-T

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Lectures via DVB-T

During the 23C3, an event broadcast service ("Veranstaltungsrundfunk") will be operated in the Berlin/Alexanderplatz area, bringing all lectures plus additional information to your personal DVB-T receiver. So don't forget to bring a DVB-T USB stick when you come to Berlin. Or buy one at the next electronics store.

What is needed to watch this?

Nothing special - any DVB-T TV set, USB stick, TFT monitor, etc. will do the job. Since most of you will bring your notebooks anyways, a DVB-T stick is probably the most reasonable way to receive the broadcast.

Will there be USB DVB-T sticks sold at congress?

Or maybe someone knows a cheap store nearby? I checked saturn.de, but they costed 70 euro... There is a shop at S-Bhf. Ostkreuz (MAGIC Eletronic Components - www.mec-berlin.de) where cheap sticks are available (Dexatek - around 38 Euros) - opened on business days from 9 to 6

  • Saturn offers a cheap DVB-T (PCMCIA) set with a very good antenna (bit larger than the normal, approx 20cm high) for about 30eur. Works fine for watching normal TV in the hackcenter, but unfortunately the congress dvb-t is not available, also not in the second floor ;-) - Validom 16:56, 29 December 2006 (CET)

Frequency, mode, parameters

Update: Our license has arrived. We now officially have permission to broadcast DVB-T on 482MHz from 26.12 to 30.12.

Channel: K22 (482 MHz), 8MHz bandwidth, 3/4 FEC, 16-QAM, 8k-Mode, 1/8 guard interval (= 16.59 MBit/s)

channels.conf:

23C3 Room 1:482000000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_3_4:FEC_AUTO:QAM_16:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:257:258:1
23C3 Room 2:482000000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_3_4:FEC_AUTO:QAM_16:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:513:514:2
23C3 Room 3:482000000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_3_4:FEC_AUTO:QAM_16:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:769:770:3
23C3 Room 4:482000000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_3_4:FEC_AUTO:QAM_16:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:1025:1026:4

Initial dvbscan file (save as file '23c3initial'):

T 482000000 8MHz 3/4 NONE QAM16 8k 1/8 NONE

To create a channels.conf file do:

$ scan 23c3initial
scanning 23c3scan
using '/dev/dvb/adapter0/frontend0' and '/dev/dvb/adapter0/demux0'
initial transponder 482000000 0 3 9 1 1 2 0
>>> tune to: 482000000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_3_4:FEC_AUTO:QAM_16:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE
Network Name 'maintechTV-net'
0x0000 0x0001: pmt_pid 0x0000 maintech GmbH -- 23C3 Room 1 (running)
0x0000 0x0002: pmt_pid 0x0000 maintech GmbH -- 23C3 Room 2 (running)
0x0000 0x0003: pmt_pid 0x0000 maintech GmbH -- 23C3 Room 3 (running)
0x0000 0x0004: pmt_pid 0x0000 maintech GmbH -- 23C3 Room 4 (running)
dumping lists (4 services)
23C3 Room 1:482000000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_3_4:FEC_AUTO:QAM_16:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:257:258:1
23C3 Room 2:482000000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_3_4:FEC_AUTO:QAM_16:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:513:514:2
23C3 Room 3:482000000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_3_4:FEC_AUTO:QAM_16:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:769:770:3
23C3 Room 4:482000000:INVERSION_AUTO:BANDWIDTH_8_MHZ:FEC_3_4:FEC_AUTO:QAM_16:TRANSMISSION_MODE_8K:GUARD_INTERVAL_1_8:HIERARCHY_NONE:1025:1026:4
Done.

Since our PA died a horrible death on Christmas Eve, we only have 1W transmission power plus 3dB antenna gain. Due to that, reception of the QAM16 signal is rather poor in the Hackcenter and outside the BCC. We will reduce streaming datarate from 3.8MBit/s per video stream to about 1.8MBit/s and switch over to QPSK modulation during the night. After that things should be much improved.

Covered area

This needs to be tested. The Bundesnetzagentur is considering to allow us a transmission with 5W power from the top of the Congress Center, which should cover the whole Alexanderplatz area. We hope that it will be possible to watch the transmission even when you're at your favourite fast-food restaurant... Besides of that, when using an external antenna you should be able to watch the congress from any elevated location in Berlin from where you can see the Alexanderplatz.

Who is doing this?

The broadcast service is part of the lecture "DVB-T - From Pixeldata to COFDM Transmission", where Thomas Kleffel and Christian Daniel are going to show their do-it-yourself DVB-T transmitter. maintech GmbH is sponsor for the license fees. Hardware is produced and provided by SR-Systems. Thomas & Matthias Kleffel and Christian Daniel have designed the neccessary software parts: FPGA firmware, protocol handling functions, table insertion, etc.

Is this about amateur radio?

Kind of - we've got amateur radio licenses (Thomas is DG5NGI, Christian is DG2NDK) and the project started as an experiment, trying to prove that even the most sophisticated modern transmission technology is still managable by amateur radio operators. Ham radio is not dead, it just needs some fresh ideas.

What is DVB-T in the first place?

Major parts of Germany have abandoned the old analog terrestial TV broadcast service and switched over to the digital DVB-T standard. The Netherlands is the first country where analog TV has been fully abandoned.

DVB-T uses COFDM modulation to gain enough bandwith for four full video streams using only the bandwidth of one old analog TV channel. For more information attend to our lecture or read the article about DVB-T on Wikipedia.