Wireless Waffle - A whole spectrum of radio related rubbish
More FM licences in London?signal strength
Monday 19 December, 2005, 15:31 - Licensed
For some time now, I've been intrigued by suggestions that Ofcom (and its predecessor the Radio Authority) is toying with the idea of issuing further licences for FM radio stations in London. Whilst the FM band in London is undoubtedly alive with stations, there is still a relatively limited number of stations on-air compared to many other major cities and the variety of programming they offer is even smaller. There is certainly commercial scope for more FM stations in London.

Currently on FM in London there are 14 London-wide and 7 local stations which are, in frequency order:

88.8/89.1 BBC Radio 2 (the lower frequency is transmitted with a power of 4kW from Crystal Palace and the higher with a power of 250kW from Wrotham, on the eastern outskirts of London. The same pattern is true for the other BBC national stations and for Classic FM)
91.0/91.3 BBC Radio 3
london93.2/93.5 BBC Radio 4
94.9 BBC London
95.8 Capital FM
96.9 Choice FM (South London)
97.3 LBC
98.5/98.8 BBC Radio 1
100.0 Kiss FM
100.6/100.9 Classic FM
102.2 Smooth FM
103.3 London Greek Radio (North London)
104.9 XFM
105.4 Magic FM
105.8 Virgin Radio
106.2 Heart 106.2
106.8 Time FM (South East London)
107.1 Choice FM (North London)
107.3 Time FM (South East London)
107.5 Time FM (South East London)
107.8 Radio Jackie

In addition to these stations, there are numerous other BBC and commercial radio stations whose broadcasts overlap from their primary coverage area into the outskirts of London, as well as many BBC relay stations to cover gaps in coverage from the main transmitter sites.

In early 2000 the Radiocommunications Agency, the Radio Authority (both now integrated into Ofcom) and the BBC conducted a study into the possibility of licensing more FM radio stations. The study considered the potential for additional stations in the FM band and sought, in particular, to identify allocations that might be used to provide new services in the London (and Leeds) area. To try and see whether it might be possible to fit more stations on the FM dial in London, the study made some very odd assumptions about what frequencies might be used in London. It took the assumption that instead of adding or re-planning stations to free up frequencies, that from 94.9 and 102.2 MHz upwards, there would be a station in London every 400 kHz (i.e. 94.9, 95.3, 95.7... and 102.2, 102.6, 103.0, etc...) and then looked at the impact that these stations would have on neighbouring stations to whom they would cause interference.

The study concluded that 'In the London area, it was found that there appeared to be some opportunity for the accommodation of further city-wide services, if the need for some re-planning of the network is accepted. For a small number of such additional services it may be that the 'cost' of the re-planning would be limited to changes in the frequencies of surrounding services and a relatively small loss of coverage by a few surrounding services. It should be noted that this study was not required to consider the constraints imposed by continental interference. If this is taken into account there will be less scope for additional services, particularly in the London area.'. Further it added that 'The scope for use of the BBC national network sub-bands was limited by the large number of high-power transmitters in this part of the spectrum. One frequency was identified, however, which might be used to provide additional London-wide service at the expense of current BBC coverage.'.

So what were the frequencies that were identified for potential new London-wide stations, and what has happened since? Well, the frequency which was identified that could be used in London with impact only on listeners in Reigate (Mercury FM on 102.7 MHz which would move to 103.6 MHz) and Chelmsford (Essex FM on 102.6 MHz which would move to 102.8 MHz) was 102.6 MHz (Fox FM in Oxford would also move from 102.6 MHz to 102.4 MHz), and the frequency in the BBC national sub-band that was identified was 92.5 MHz, which it was claimed would upset virtually all the listeners to the BBC Radio 4 service in Guildford on 92.5 MHz who instead of their current 4kW service would get a 50W low-power service on 93.7 MHz. It would seem that since the publication of this report, nothing has happened. No action was taken by any of the parties involved to instigate any changes which might bring about a new license.

Rumours have since surfaced that the frequency of 87.6 MHz might also be used in London. This frequency (actually any frequency in the band 87.6 to 87.9 MHz) is currently reserved for low-power RSL stations, however there is no regulatory reason why a new, high-power, London-wide service could not use this frequency (with the possible problem of the need to co-ordinate with RTL on 87.6 in Lens in northern France). Whilst this would restrict the potential for RSL stations, it would not cause interference to any other UK stations as the band is otherwise unused. Further, the 3 Time FM stations in neighbouring parts of south east London which were previously different stations could now be consolidated onto a single frequency and the band between 106.8 and 107.5 re-arranged to release another London-wide assignment. It has also been postulated that a frequency around 101.6 MHz could be used for a London-wide service (subject to finding a new home for Kent based KM-FM on 101.6 MHz and possibly Ten-17 in Harlow on 101.7 MHz). The original study did not consider the 107 MHz frequency range, nor did it consider 101.6 MHz.

So potentially there are five frequencies which could be released for new stations: 87.6, 92.5, 101.6, 102.6 and somewhere around 107 MHz. With the exception of 87.6 MHz, none of these provides an interference free answer to new London-wide stations, but there seems to be no reason why Ofcom could not look to offer new licenses in London. With the propensity of pirate stations in the capital, there is clearly excessive demand for stations, so why is Ofcom so reluctant to consider a new station or two?

Maybe there is pressure from the existing licensees not to introduce further competition, whilst there is clearly competition between the existing stations, working together as a cartel to block any additional competition is clearly in all of their commercial interests. Maybe Ofcom is busy with other things (for example the raft of community licences recently issued). Or maybe it's just that the people who looked at the problem in the first place have now moved on since the reorganisation that formed Ofcom and no one has been tasked with reviewing the study and taking the necessary action. I'm not sure that there's anything that can be done to 'gee-up' Ofcom, however I felt that raking up the old muck again might just stir some action somewhere.
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The Digital Dividesignal strength
Thursday 27 October, 2005, 09:45 - Licensed
Posted by Administrator
http   www mf2fm com blog  dabradioAfter many years in a sleepy backwater, Digital Audio Broadcasting (DAB) in Europe is finally becoming more mainstream (with one or two exceptions). This is certainly in part due to the fact that the prices for DAB receivers have now dropped to the level where, when buying a new radio for the kitchen, a DAB radio is in the running; and with the extra stations and 'improved quality' they offer, DAB radios are now becoming a must have item.

However, the gradual move towards DAB brings with it a problem for local FM broadcasters whose coverage is limited to a relatively small geographic area. For you see, DAB works by means of a multiplex (mux), whereby a number (typically 8 or more) stations are combined together and transmitted from one or more transmitter sites. The content of the mux must remain identical on all the sites such that all the stations on the mux achieve exactly the same coverage area. This is fine for national stations and for those who cover a relatively large geographic area, or the same city, such that there are likely to be other broadcasters who wish to achieve the same coverage and could share a multiplex; but who would wish to share a multiplex and duplicate the coverage of a neighbourhood or a small rural enclave? The straighforward answer is no-one! So these small scale stations are left with no option other than to continue using FM and hope that DAB does not become the de facto broadcasting standard.

Salvation, however, may come in another form of digital radio, otherwise known as Digital Radio Mondiale (DRM). DRM is designed to offer a replacement for outmoded AM radio on the long, medium and short wave bands, but it has recently had its frequency range extended to 120 MHz so as to offer a possible replacement for FM broadcasters too. For existing AM broadcasters, a move to DRM offers the chance to replicate their existing coverage but with much improved quality ('near-FM quality' is often quoted as being achieveable in an AM channel using DRM).

For AM broadcasters, this is great news: Using the same spectrum they can improve their transmission quality and many broadcasters, especially in mainland Europe, have already done so.

http   www mf2fm com blog  drmradioUsing DRM in the FM band is a largely untried quantity and in theory there is no reason why it could not only work but at the same time expand the number of stations that could be broadcast in the FM band, as a DRM transmission takes up only about one tenth the bandwidth of an analogue FM transmission. It may not, though, be an ideal solution for a local FM broadcaster, particularly as at present, the very few receivers that exist for DRM do not cover the FM band (the manufacturers assumed that the standard would only be used on the HF bands below 30 MHz). Also (and I'm sure there are cleverer people than me working on this), the carrier spacing for the OFDM signal of a DRM transmisison varies between 41.66 and 107.5 Hz. At a frequency of 108 MHz, a vehicle travelling at 250 km/h (a train for example, or a BMW on a German motorway) experiences a Doppler shift of 25 Hz. Compared with the 41.66 Hz carrier spacing this is significant, and even at 107.5 Hz carrier spacing it represents a significant difference for the receiver to have to track, and must introduce lots of errors in reception.

http   www mf2fm com blog  ukfat26There is another cat in a bag which offers a potential solution to the question of a digital replacement for local FM broadcasting in the shape of a little used HF broadcast band. The 11 metre band (25670 - 26100 kHz) is virtually unused by broadcasters as, other than at the peak of the 11 year sunspot cycle, propagation is virtually non-existent except for local ground-wave coverage. During the day at the peak of the cycle, signals travel thousands of miles, especially trans-equatorially (i.e. north to south and vice versa). Experiments have been conducted in Germany which showed that using DRM in the 11 metre band offers good local coverage similar to that which FM enjoys, however there is the potential for occasional long-distance interference during the day. This is, if anything, an improvement on the situation which traditional AM broadcasters enjoy in which there is a virtual guarantee of interference from distant stations every night!

Experiments using the 11 metre band are continuing in Germany and France and in London by WRN (1kW on 26070 kHz from Crystal Palace) and if all goes well, I think we could see a raft of local stations opening up DRM transmissions in this band, complementing their FM coverage and giving them a digital outlet to compete with the growing number of DAB stations. For the sake of small local radio stations, let's hope so.
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