DRM in Band III – Your Question Answered

DRM in Band III – Your Question Answered

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Your literature on mentions that DRM also works in band III. Is this possible?

(Broadcast engineer, Poland) 

Add a subheading (5)

The DRM digital radio standard, as recommended by ITU can work in all VHF bands (I, II, III). For DRM, or any other digital audio standard, to work in band III this must be available, as historically this was the band for analogue TV. When it is used by TV, it presents a sequence of channels of 7 MHz bandwidth, except in the Americas where a channel is 6 MHz wide. 

One Band III TV channel can carry only one of the following, while leaving an interference buffer zone: 1 TV transmission channel carrying 1 or more TV programmes; about 4 DAB+ transmission channels carrying up to around 72 sound programs and 1 – 68 DRM transmission channels carrying up to a total 204 sound programs. 

Band III has its own characteristics and the higher the frequency, the lower the electrical efficiency of transmitters. 

As band III is still occupied by analogue TV in many countries of the world, an easy digitisation solution is using DRM for immediate and efficient introduction of digital radio in VHF band II (FM band).