Introduction to Wi-Fi radios

BBC may move one or more stations onto Digital One

The Mediaguardian has reported that the BBC is looking to move the Asian Network plus the possibility of "one or two" other stations onto Digital One. The Mediaguardian article went on to suggest that the capacity freed-up on the BBC's national DAB multiplex would allow the BBC to either launch new services or improve the quality of existing stations. I asked the BBC about this, and a spokesman said that:

"[The BBC has] no plans to launch new services"

So if the BBC does move station(s) onto Digital One it would solely translate into the quality of existing stations improving.

This should also answer the very common suggestion that once the BBC switches over to DAB+ it would simply launch lots of new stations and there would be no improvement in quality. This was never realistic in the first place, actually because the AAC/AAC+ codec used on DAB+ is so much more efficient than the MP2 codec on DAB that it would require the BBC to launch another 10 or more new stations for there to be no improvement in quality compared to today, which was never going to happen.

As well as improving the audio quality of its stations using DAB, another advantage is that it would make the BBC's transition over to DAB+ easier than how it would be with the multiplex as cramped as it currently is.

If only the Asian Network moved to Digital One

The Asian Network moving to Digital One would free up 64 kbps of capacity.

The benefits of this are as follows:

• The bit rates for Radio 1 and Radio 2 would be able to increase from 128 kbps to 160 kbps
• Radio 3 wouldn't have to be reduced to 160 kbps and Radio 4 wouldn't need to be reduced to 80 kbps mono when Radio 5 Sports Extra goes on-air

The negative implications of this are:

• The bit rates for Radio 1 and Radio 2 would have to be reduced back to 128 kbps whenever Radio 5 Sports Extra is on-air -- which seems to be on-air a lot of the time these days...
• 6 Music would still permanently be using 128 kbps
• 1Xtra would still permanently be using 128 kbps
• Radio 7 would still have to be broadcast in mono

Overall, if only the Asian Network moved onto Digital One then I would consider it to be pretty much as bad as if there had been no improvement in quality at all, mainly because the BBC would still be using 128 kbps MP2, which provides dire audio quality, for R1 and R2 for a lot of the time and 6 Music and 1Xtra all of the time.

If the Asian Network and 1Xtra moved to Digital One

1Xtra uses a bit rate of 128 kbps, so moving this along with the Asian Network over to Digital One would free up 192 kbps altogether on the BBC national DAB multiplex, which equates to 144 CU of capacity (capacity on a DAB multiplex is measured in capacity units, or CU, rather than bit rate).

The following table shows the changes the BBC could make if both the Asian Network and 1Xtra moved to Digital One (note that DAB multiplexes always have a capacity of 864 CU -- there's a table of bit rate versus CU on the page showing current and previous BBC DAB multiplex configurations):

The reason for increasing Radios 1 and 2 to 192 kbps is because that's the bit rate Radios 1 and 2 were using on DAB in 2001 -- before the BBC disgraced itself by launching five new stations on its multiplex which only had room to carry two new stations. 192 kbps is also the bit rate the BBC is using for Radios 1 and 2 on Freeview and the other digital TV platforms.

The above changes also reflect the fact that speech is a lot easier to encode than music, so music stations need to use significantly higher bit rates than speech stations to attain the same level of quality -- which is why the bit rates for Radio 4, Radio 5 and the World Service haven't increased in the table.

As the Digital One multiplex is so empty at the moment, the BBC could basically choose to use whatever bit rates it likes for the Asian Network and 1Xtra on Digital One.

The BBC would no doubt reduce the bit rates of Radios 1 and 2 to 160 kbps when Radio 5 Sports Extra is on-air, though.

This configuration would lead to much better audio quality overall.

If three stations moved to Digital One

If 1Xtra, the Asian Network and Radio 7 moved onto Digital One, the remaining stations on the BBC national multiplex could use the following bit rates:

It's interesting to note that the bit rates for Radio 1, Radio 2, Radio 5 and the World Service above are still no higher than the same stations are using at the moment on the digital TV platforms -- which shows just how grossly incompetent it was to add five new stations to the BBC's national DAB multiplex in the first place.

Digital One doesn't broadcast in Northern Ireland

If the BBC were to withdraw a station from Northern Ireland it would likely be 1Xtra due to the station being targeted at young black people, and according to the 2001 Northern Ireland census, only 1,136 black people lived in the province out of a population of 1.7 million, so the BBC may consider it to be acceptable to withdraw the station under those circumstances.

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