[cma-l] Extending Community Radio on FM

Sat Sep 27 17:18:45 BST 2014

Alan - I don't recognise most of the scenario you describe here as being the UK Regulation system that we're working in today.Protection Ratios set up by IBA and RA were adopted by the ITU 50 years ago and are unlikely to change?
Not really indicative of any positive progress then.In my experience Ofcom doesn't do much on an "ad hoc" basis - quite the opposite.Commercial operators and indeed all licensed broadcasters are more than adequately protected in technical terms and all expect signal corruption on occasions when it's caused by unavoidable atmospheric conditions.Enhancement of coverage by any broadcaster is not easy - and is approached by Ofcom on a low-priority and individual merit basis - unless of course pressure is brought to bear.I would think we can all quote examples of that apparently happening.Commercial stations had power and frequency allocated in exactly the same was as is used for Community Radio - desired coverage against regional spectral occupancy.Standalone or mini-mux DAB is a long way off and should not be offered as an excuse for not dealing with the present and very real need for a seed-change in spectrum manipulation for best efficiency.There are scores of local stations out there which are ready to go on air and around half of them will be refused for what appear to be insecure and what we are told are incontestable reasons.This is not the form of Democracy that we should expect from a UK Government and its Agencies.
From: alan.coote at 5digital.co.uk
To: cma-l at mailman.commedia.org.uk; info at a-bc.co.uk
Date: Fri, 26 Sep 2014 14:06:28 +0100
Subject: Re: [cma-l] Community Radio on AM

The FM protection ratios were set up using a specs’ based on the selectivity and sensitivity of radios in the 60s. The IBA, Radio Authority and Ofcom planned licences based on their analysis of available frequencies using this spec’. It became an ITU standard so is very unlikely to change.      Fitting new stations on an ad-hoc basis has the danger of commercial operators being disadvantaged through interference, however occasional.  Picking up Nick’s point about Silk FM getting more power, this has happened numerous times around the UK. It’s because commercial stations are licenced to use a preallocated and cleared frequency by Ofcom. Should a licenced station make a case that either Ofcom’s analysis was wrong, or over time the area has changed, then Ofcom will need to reflect that by permitting changes to the coverage. This is of course a totally different scenario from the way community stations start life.    At the end of the day Ofcom is full of people whose job it is to run things by the rules. There is absolutely no advantage to them doing otherwise.  In my view a better baton to wave is for access to DAB via standalone stations – here the rules aren’t even set.                 Kind RegardsAlan   Hear Alan Every Week on Let’s Talk Business The UK’s Premier Radio Programme For Current and Future Entrepreneurs - Now Broadcast To 4.3 Million People   Email - alan.coote at 5digital.co.ukPhone - 0800 949 6655Mobile - 07801 518858Twitter - @TheAlanCooteWeb - http://www.5digital.co.uk The Media Production, Broadcasting and Training Company From: cma-l-bounces at mailman.commedia.org.uk [mailto:cma-l-bounces at mailman.commedia.org.uk] On Behalf Of Ian Hickling
Sent: 25 September 2014 08:23
To: The Community Media Association Discussion List; Associated Broadcast Consultants
Subject: [cma-l] Community Radio on AM I don't agree that ".....proper computerised tools are needed to do it properly" Glyn - sorry.Computerised tools have got us into the farce that we are currently in.Certainly we need proper planning - but after that we need practical onsite trials as you say with measurement and analysis.This however is costly in terms of the equipment and manpower which Ofcom does not have available and is not going to get funded by HMG.So Ofcom could do it but won't.
Lots of us can do it - but Ofcom doesn't accept that concept.From: tlr at gairloch.co.uk
To: info at a-bc.co.uk
Date: Wed, 24 Sep 2014 18:11:01 +0100
CC: cma-l at mailman.commedia.org.uk
Subject: Re: [cma-l] Community Radio on AMI understand the 'complex scientific' side of it, but I still don't honestly see how the map helps give any insight other than in the crudest measure of overall density of stations.  It shows the general density of stations and is a nice tool for browsing stations and frequencies, but it gives no visual representation whatever of frequencies or powers, so I don't honestly see how it gives even the vaguest insight into the interference landscape for a station. It could maybe take useful steps in that direction with some development. For example if one could select a frequency or transmitter of interest and set a filter to show only stations of that frequency, or of that frequency plus adjacent and/or image channels it would start to give an idea of potential for interference. Combined with perhaps a crude free space range indication using semi-transparent overlays based on on powers and direction templayes it might beging to give a rough feel for the interference landscape for a given station. But as it stands I don't see how it does that in the slightest. Not meaning to be picky, honest - I like it for what it is, and it does give a feel for the geographic distribution of CR stations, but it doesn't seem to me to offer any useful insight or even vague feel for the interference landscape.
Alex----- Original Message ----- From: Associated Broadcast Consultants To: Two Lochs Radio Cc: The Community Media Association Discussion List Sent: Wednesday, September 24, 2014 5:37 PMSubject: Re: [cma-l] Community Radio on AM Absolutely right Alex - the frequency selective map would only be for getting an "insight" or feel for the interference landscape - proper computerised tools are needed to do it properly.  It's complex and scientific, but this post below gives a pictorial, non-technical insight into the "Protection Ratios" that Ofcom use, and are one of the reasons they often say there are no frequencies available:- http://a-bc.co.uk/ofcom-fmvhf-protection-ratios-illustrated/  Glyn -- 
Glyn Roylance - Principal Consultant Associated Broadcast Consultants On 24 September 2014 16:58, Two Lochs Radio <tlr at gairloch.co.uk> wrote:Hi Glynn That's a nice map for browsing, but as far as mapping all transmitters to allow assessment of potential interference, it surely isn't the way to go. As you'll be well aware you need much more than a simple mapping of potential co-channels - you have to take into account image channels and the directional power templates of antennas at the very least, even before thinking about the intervening terrain.  You also have to take into account transmissions in neighbouring countries of course. I think all that can be done far more effectively in tabular form than on a map. Of course, the elephant in this particular room is not in any case what frequencies are or aren't occupied, but what parameters Ofcom applies in assessing their potential for mutual interference - eg should a 99% confidence level or a 90% confidence level be used, should second adjacent channel be regarded as safe or not? Those are what make all the difference to the assumed potential for interference between transmitters. Similarly, is potential interference acceptable for 0.1% or 1% of the time or location? All these parameters are really what set the technical bar as to whether or not there are channels available.  Then of course there are strategic and political issues, agrements for the BBC to have priority use of certain sub-bands etc. One thing that could be considered for releasing more community radio frequencies is for Ofcom to reuse channels more closely on the basis of a mutual agreement between stations that they will not complain about the remote possibility of mutual interference less than say 1% of the time in 10% of their fringe. We have transmitters on the same frequencies just a few miles apart, but terrain-limited with no significant mutual interference in locations of interest, because we were able to agree not to complain about our transmitters interfering with each other! A similar thing happens on 96.6 between Nevis Radio (Fort William) and MFR (Aviemore) in the Laggan area half way between them. I suspect many groups would be willing to accept a service that might be subject to a little marginal interference in some limited locations rather thna no licence at all. As for suggestions on the map, which is nonetheless nice to have, could I suggest you add in the Scottish not-for-profit stations that operate as non-profit community stations, but for historical reasons have commercial licences (Cuillin FM, Two Lochs Radio, Lochbroom FM, Argyll FM, Oban FM, Isles FM). That would give a more representative picture of community radio cover in the northwest of the UK, which otherwise looks a bit empty on the map! There are also community op-outs from MFR in the north-east. Also for adding the Northern Ireland stations there is a batch convertor for Irish grid references here http://www.osi.ie/calculators/batch.asp?alias=/services/gps-services/co-ordinate-converter Alex  ----- Original Message ----- From: Associated Broadcast Consultants To: The Community Media Association Discussion List Sent: Wednesday, September 24, 2014 2:54 PMSubject: Re: [cma-l] Community Radio on AM Further to Ian's update below - we recently mapped the Ofcom data for FM CR's onto an interactive Google Map that you can browse, zoom etc.  If you click on any site if gives the essential information.  http://a-bc.co.uk/community-radio-station-map/ If there is interest we might do a similar map for all UK transmitters (nearly 2000 of them) that you can filter by frequency - thus to get an insight into co-channel interference for any station/location/frequency you wish.  Or other variations if people have suggestions. Regards, Glyn 

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