ARLA/CLUSTER: Rádio revolution will leave listeners in silence

[João Gonçalves Costa]

Yesterday's Daily Telegraph featured an article by Libby Purves titled: 'Radio revolution will leave listeners in silence', in which she describes DAB technology as 'energy-guzzling' and queries the need to abandon the analog bands.

One of the many people who found themselves in complete agreement with Libby's view was Practical Wireless editor Rob Mannion, G3XFD. 

Rob's edited response to the article can be seen here: 
www.telegraph.co.uk/comment/letters/5614062/The-election-of-the-new-Speaker-shows-that-MPs-have-learned-nothing.html

However, the Daily Telegraph's editing of Rob's letter may have inadvertently resulted in its readers being given the impression that he was endorsing DAB radio when, in fact, the reverse is true. 

So, we have reproduced Rob's letter in full below.

>From Rob Mannion
Editor of Practical Wireless magazine
Arrowsmith Court
Station Approach
Broadstone
Dorset BH18 8PW
01202-659910

Digital Radio Broadcasting

Dear Sirs: In it's seemingly rushed statement regarding digital broadcasting technology - in particular the replacement of high quality frequency modulated (f.m.) broadcasting on the Band II v.h.f. broadcasting allocation (often referred to as the 'VHF FM' band) - the Government seemed to have either ignored, or aren't aware of the practical problems that could be in store for the vast majority of radio listeners.

Digital Audio Broadcasting (DAB) services as transmitted within the old Band III television channels can - but often don't - provide excellent quality reproduction, depending on the audio bandwidth provided by the broadcaster. The quality of the reproduction often heard on the DAB broadcasts often compares very badly with the (when available) Freeview terrestrial Digital TV system radio channels. In fact, the BBC Radio 3 and 4 services can be truly superb when used in conjunction with a properly set up antenna system and it's very often the poor antennas - with less than satisfactory DAB transmission levels - that can, and do, cause real problems for the digital radio service user.

With conventional f.m. transmissions on Band II v.h.f. f.m. services  it's not often the listener runs into insurmountable reception  problems, even though the vast majority are using portable receivers with less than adequate telescopic antennas. Occasionally, the low level stereo pilot tone lost, and only mono reception is possible -  but the programme can still be heard and if the receiver is moved  (perhaps to a window or another part of the room) reception can be perfectly adequate.

However, with digital techniques there is a significant delay of several seconds in decoding the signal. So, whereas with the existing system the listener - who can range from the very young to the very old and infirm - could find it extremely difficult to tune into a particular programme because the decoding delay (referred to as latency) could lead them to believe an otherwise suitable position for the set, wasn't suitable, when it actually was but was masked by the decoding delay. It can be extremely frustrating - as anyone who has tried to set up a portable TV satellite system receiver dish antenna on holiday will have discovered. It takes real patience at times!

>From my own experience, I know that the vast majority of v.h.f. domestic radio reception is achieved via portable sets with relatively inefficient Band II antennas. However, the less than satisfactory Band II coverage within the UK is another matter and personally, I hope that the Droitwich 198kHz transmitter service and its two associated Scottish transmitters will be available for many years to come, as it's so reliable, providing reception to the far west of Ireland and to the northern mainland of Scotland, acting as a back up when v.h.f. coverage is poor or non-existent.

Basic amplitude modulated (a.m.) radio on long and medium waves may not be 'hi tech' - but is extremely reliable and essential in cases of national emergency due mainly to the simplicity and availability of easy-to-use receivers. The next step up, the use of v.h.f. using f.m. techniques is also well suited to domestic use. On the other hand DAB radio, whether it be on Band II or on Band III is not suited - in many cases - for use with the 'take anywhere' portable , which the vast majority of listeners use.

Rob Mannion

Dr. R. B. Mannion
Medical, Science & Technology Editor/Writer and Journalist 
 

 

DAB technology 'energy-guzzling' ? 
http://www.southgatearc.org/news/june2009/dab_technology_energy_guzzling.htm 


Practical Wireless
http://www.pwpublishing.ltd.uk/