2018-02-24

DAB/DAB+ digital radio in Greece





A few weeks ago, the government controlled broadcaster ERT started transmitting a DAB+ multiplex from their transmitter site on Mt Ymittos, near Athens (HGRS87 coordinates: 483892, 4200920; WGS84 coordinates: 37.9583 N - 23.8183 E; 945 m ASL). Before that, the Minsitry of Digital Policy, Telecommunications and Information had published two relevant ministerial decisions in the Government Gazette. Decision 169/2018 defines the allotements and frequency allocations for DAB broadcasts in VHF Band III (174-230 MHz) and authorized a number of transmitter locations. Decision 170/2018 issues a license to ERT for nationwide DAB+ broadcasts on one frequency in each allotment.

Currently an experimental ERT transmssion on 227.36 MHz covers only part of Attica Region. The multiplex contains the following audio streams:
  • "PROTO" (136 kbps,  AAC)
  • "DEYTERO" (136 kbps, AAC)
  • "TRITO" (136 kbps, AAC)
  • "ERA SPORT" (96 kbps, AAC)
  • "KOSMOS" (128 kbps, AAC)
  • "Voice of Greece" (96 kbps, AAC)
  • "ERA 7" (64 kbps, AAC)
The channel characteristics were logged in the afternoon of Satruday, February 24, 2018; they may change over time while ERT engineers experiment with coverage and sound quality issues. 

Voice of Greece is also transmitted at irregular times, usually during late nights, in short wave, on 9420 kHz.  

"ERA 7" transmits audio from the sessions of the Greek Parliament. 

"TRITO" is supposed to transmit high fidelity music, however the current bitrade is inadequate, as 192 - 256 kHz is the minimum acceptable bitrate for this purpose.

My vintage MagicBox Clarus Plus DAB/WiFi digital desktop radio receiver can receive all seven channels with its whip antenna, however the signal strength is weak and the error rate relatively high.

For general and technical information about DAB, access to the relevant ETSI standards and other updates, visit the WorldDAB Forum at: https://www.worlddab.org/ 






4 comments:

  1. Regarding the bitrate for "TRITO" (3rd programme): In comparison, BBC Radio 3 uses 160-192 kbps with the AAC CODEC. On the other hand I believe that 136 kbps for "PROTO" is a waste of bandwith, as this is a basically a (boring) news and talk service.

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  2. Bitrates in the morning of Monday, February 26, 2018:
    - "PROTO": 136 kbps
    - "DEYTERO": 136 kbps
    - "TRITO": 136 kbps
    - "ERA SPORT": 128 kbps
    - "KOSMOS": 128 kbps
    - "Voice of Greece": 96 kbps
    - "ERA 7": 64 kbps

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  3. Bitrates in the morning of Tuesday, March 6, 2018:
    - "PROTO": 136 kbps
    - "DEYTERO": 136 kbps
    - "TRITO": 136 kbps
    - "ERA SPORT": 128 kbps
    - "KOSMOS": 128 kbps
    - "Voice of Greece": 96 kbps
    - "ERA 7": 64 kbps

    Also improved (almost zero) Bit Error Rate. Did they increase power or improve the antenna pattern?

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  4. Bitrates in the afternoon of Sunday, March 25, 2018:
    - "PROTO": 136 kbps
    - "DEYTERO": 136 kbps
    - "TRITO": 136 kbps
    - "ERA SPORT": 128 kbps
    - "KOSMOS": 136 kbps
    - "Voice of Greece": 96 kbps

    I don't understand the logic, TRITO should be 196-256 kbps, while for KOSMOS 128 is a waste of bandwidth.
    - "ERA 7": 64 kbps

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