The BBC’s year-long test of digital mediumwave radio proved a hit during daylight hours but was a serious turn-off for its band of volunteer listeners after sunset.
The trial, held in the south-west of England with a frequency used by BBC Radio Devon and codenamed Project Mayflower, revealed that the area covered by the DRM signal was much bigger than the one covered by analogue AM.
Reception during daylight hours was good and most panellists rated the audio quality as comparable to FM, but not as good as DAB. However, at night there were serious problems with reception, with the signal breaking down entirely in some cases. The BBC said the problem could be solved, but would require it to replan its transmission network or build more powerful transmitters.
- Read the full story in Media Guardian
- Project Mayflower (full BBC report)
on May 23rd, 2009 at 17:25
This learns that there is hardly any difference between broadcasting analogue or digital on AM bands. The same problems concerning reception caused by fading and skywaves from co-channel users. I guess digital reception stops at certain moments. where analogue goes on, albeit with the interference noise.
I guess sound quality is better with DRM, but even this mihgt hardly make much difference if the analogue TX is well adjusted and takes just a little more bandwith. Even taking more bandwith in analogue transmitting causes less annoyance and noise then a DRM signal, which is properly fitered but since the outpput is at max power in the whole 9 kHz spectrum it is giving more noise in the adjacent cahnnels then wideband analogue..
And analogue receivers are there with the public, by billions, no DRM receivers.
So keepo it simple and cheap. leave the AM band analogue
Untill on-line radio has taken over FM and AM.
on May 24th, 2009 at 01:00
The problem with the UK is that we use such low power on our local AM transmitters.
Most local local BBC stations only run between 100 Watts - I kW. The Commercial stations are even lower power - so with some French stations using 300 kW and other high power European stations on the same frequencies, it\’s no wonder the reception of UK Medium Wave stations is dire at night.
on Jun 1st, 2009 at 06:36
More powerful transmitters would probably improve things;several hundred watts of AM rather than several hundred kW of AM as used by BBC Local Radio and commercial stations seriously reduces the service area coverage at night possible in DRM-MW transmission. BBC Radio Lancashire has two MW tx\’s which each radiate 250w and 500w respectively, the 500w mast at Riley Green near Preston Lancs which serves Central,Western and North Eastern Lancashire with some coverage to South Lancs too which goes bad after dark with excessive fading and the second 250w MW tx up at Oxcliffe Hill near Lancaster which has a directional beam serving the Fylde Coast and N.Lancs with a limited overspill to parts of the South Lakeland Furness area. I believe there is a strong case for the local and commercial stations around the UK to increase their powers to higher kW levels to cover bigger areas rather than poor low level hundred watts of AM power levels to improve reception in MW analogue and eventually DRM-MW transmission as they go.