Eureka! Online

DAB+ trial in South Africa – Moving towards a digital future

Lynn Mansfield, Chairman,
Southern African Digital Broadcasting Association (SADIBA), and Executive Advisor, South African Broadcasting Corporation  (SABC)

As in many territories, broadcasting in South Africa is evolving to cater for digital services as FM spectrum is limited, preventing opportunities for new broadcasters and content.  DAB provides long term transmission and network savings, along with new revenue opportunities thus making migration to digital radio a viable option for South Africa.

Setting up the trial

In 2012, SADIBA and the NAB formed a DAB+ trial Working Group with the goal of identifying a broadcasting standard for digital radio.  This led to a trial licence being granted by the Independent Communications Authority of South Africa (ICASA) with State owned broadcasting signal distributor Sentech chosen to test the digital radio technology.

The purpose of the trial is to test and evaluate DAB+ against the following criteria:

  • End to end technical functionality (studio to receiver)
  • Extent of portable mobile coverage (moving vehicle)
  • Signal permeability – building penetration
  • Effects of vehicle penetration loss
  • Interference and clutter on coverage (high rise buildings)
  • Demonstrate value added services, Dynamic Label System (DLS) and Colour Slideshows
  • Field testing typical professional and consumer equipment
  • Testing Audio quality at different data bit rates
  • Testing the concept of Pop-Up Stations on DAB+
DAB+ trial demonstration

DAB+ trial demonstration

Technical parameters of the trial

The trial began on 3 November 2014 and consists of two high power transmitting stations in Johannesburg and Pretoria in the province of Gauteng covering approximately 21185km2.  The total gross population covered in this trial is approximately 11 million (22% of South Africa’s population).  The two stations operate in a Single Frequency Network and will be evaluated separately as well as together in SFN at 2kW, 5kW and 10kW. Eighteen stereo channels are available on the trial, allowing 40 public and commercial radio to participate on a rotational basis to give each broadcaster a chance to trial (A 19th channel will be added shortly.)  The trial tested the audio quality from 32kbps to 128 kbps at 48khz sample rate with various broadcasting formats, parametric stereo and data speeds at 8Kbps and 16 Kbps.

DAB+ coverage in Gauteng

DAB+ coverage in Gauteng

DAB+ trial achievements

A report of findings of the Johannesburg portion of the trial showed that the DAB+ trial has so far achieved the following objectives:

  • End to end technical functionality was achievable
  • Performance evaluation of domestic receivers and professional measurement equipment in the coverage area proved to be satisfactory
  • Portable or mobile coverage was evaluated with the use of domestic receivers and a professional receiver and proved to be satisfactory
  • DAB+ domestic receivers with the functionality to display value added services (picture slides) demonstrate the correct functionality as well as the advantages of this additional functionality
  • Overall performance of the domestic receivers and professional measuring tool exceeded expectations
  • 2kW Transmitter power – Line of site (LOS) or near Line of site (NLOS) propagation paths are required to ensure sufficient coverage and good service quality. Insufficient coverage and bad service quality was experienced in No Line of Site (NoLOS) areas
  • 5kW Transmitter power – Coverage and service quality in NoLOS areas were greatly improved as well as in surface clutter conditions and penetration into vehicles. Building penetration was however still a slight problem
  • 10kW Transmitter power – a much denser coverage was provided with sufficient signal to penetrate through most of the buildings evaluated
  • Measured coverage results were correlated with the predictions and the following findings were made:
    • 2kW – coverage predictions ±1dB higher than predicted
    • 5kW – coverage predictions ±2dB higher than predicted
    • 10kW – coverage predictions ±2dB higher than predicted

Next steps and trial extension

An application for a 2-month trial extension from ICASA has been accepted to complete phase 1 (network verification process) and an application for a new one-year trial licence to complete phase 2 (audio and data testing) and phase 3 (closed user group listening tests and a simulation of a “commercial launch”) of the trial in 2016 is to be made.

Positive steps towards South Africa becoming digital have been made and the next phase is to ensure that a regulatory framework is put in place to enable the licensing of DAB+ radio in South Africa.

References

DAB+ Johannesburg (T97) Measurement report

One comment on “DAB+ trial in South Africa – Moving towards a digital future

  1. G Ernest Hardwick
    May 12, 2016

    I am listening to your new test and merely wish to comment that while the broadcasts are clear they are insufficiently detailed for good music especially full range classical music. I am not a technical person but the transmission is a maximum of 80 mbps and less on some stations which appears to be insufficient. Even to my untrained ear switching to the ordinary FM station one can hear the sound is more detailed.
    Will this be the norm?

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