|dc.description.abstract||Digital Terrestrial Television (DTT) originates from the Regional Radio Communication Conference of 2006 (RRC06) and the subsequent Geneva 2006 agreement (GE06) of International Telecommunication Union (ITU) recommendations which made a resolution that member states signatory to the agreement must migrate from analogue to digital television broadcasting services. This was due to the frequency spectrum scarcity in order to accommodate mobile telecommunication services because the terrestrial TV frequency spectrum would no longer be exclusively used for terrestrial broadcasting. The resolution objective resulted into planning for Terrestrial-Digital Audio broadcasting (T-DAB) in the VHF range (174-230 MHz) and Digital Video Broadcasting (DVB-T) in the UHF range (470-862 MHz) of the television frequency spectrum.
Digital television system is latest initiative to impact Zambian television broadcasting systems since black and white conversion to color television transmission in the 1980’s. DTT is modern and utilises advanced technology, which employs digital modulation techniques for the broadcasting of television services rather than analogue amplitude modulation system. This study highlights various technical factors that are critical to the success of DTT implementation in Zambia. The focus of this research is made to evaluate in details the DTT implementation plan, validate optimal application of Single Frequency Network (SFN) and Multiple Frequency Network (MFN) in order to attain full DTT coverage in Zambia. Furthermore, the footprint of DTT coverage, field signal strength levels, modulation and bit error rates of selected coverage areas were determined.
Simulations were made with accurate and update input data (antenna height, location, gain, transmit power, DVB-T2 parameters, etc) for the TV transmitting stations as provided by Zambian Government through the Ministry of Information and Broadcasting Services.
Finally, the calculated-simulated results were validated with signal field strength measurements using portable TV test receiver, indoor, a high precision calibrated and ordinary YAGI antennas. The simulated results ranged between 81.0 to 53.0dBμV/M and signal field strength measured values ranged from 70.2 to 41.2 dBμV/M, respectively. From both results, it was observed that MFN provided large signal coverage areas in relatively large flat lands and SFN in complex geographical terrains like Kafue and Chingola. Gapfiller transmitters (low power transmitters) were recommended and to be installed in areas where MFN and SFN networks did not provide threshold signal field strength for set top boxes (STBs) to lock to DTT signal like Mazabuka and Chibombo. Vulnerable areas where digital terrestrial transmission would be a challenge to provide minimum signal strength for STBs to lock, the alternative recommended solution would be to obtain direct-to-home (DTH) satellite feed.||en