[cma-l] Community Radio on AM

[Tony Bailey]

 From an AM perspective, the old steam radio has been there and done 
most of this - sharing channels, synchronised oscillators - jamming - 
offset carriers you name it, all to try to overcome the limitations of 
the spectrum.  If you have super expensive receivers it helps, the 
problem with that is we increasingly don't have that option.  At least 
with a ferrite rod antenna you could null out (even jamming) the 
unwanted station.  There is also the strategic need to limit competition 
- once again AM has been there: it was strongly argued for years that 
there was no room on the medium wave band for commercial radio!

I don't believe you will get anywhere with this until the community has 
it's own slice of the cake in band 2 (as do the BBC and ILR in 
principle).  It has long been accepted that low power radio should have 
a separate allocation.  As I understand it, there are now ways to reduce 
the 2.2 MHz national network slot, doing this with all five would 
release two chunks for CR.  Surely there is an argument that if the 
nationals are not going to move to DAB yet, they are squatters?

Regards,  Tony Bailey

On 25/09/14 08:23, Ian Hickling wrote:
> 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 AM
>
> I 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
>

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