If you’re applying for a community radio licence in Ofcom’s third round over the next few years, there are a number of issues you need to be aware of around FM frequency availability.


Because of the success of the first two rounds of licensing, Ofcom has made it clear that in many built-up urban areas of the UK, all the available FM spectrum is now being utilised by other services. A rough list of affected areas can be found in the Notes of Guidance - and more detailed lists of specific local authority areas affected are published as each region’s formal advertisement is made. When reading the Notes of Guidance, it should be assumed that areas mentioned refer to local authorities, rather than historic counties or any other geographic region. Frequencies can become available in areas where there were previously none–for instance, in the unfortunate event of a station closure. Ofcom will update their website should this become the case in your area.

If you are at all in doubt as to whether the area you wish to cover is affected by the lack of frequencies, please get in touch with the Community Radio Licensing team at Ofcom who will be able to clarify matters. It’s far better to take the time to ensure you can apply now, than go through the time and expense of formulating an application only to find that technical matters stand in your way.

Even if you are located outside a congested region, there are several steps you can take to minimise the impact of your signal on neighbouring regions and maximise the chances of being allocated a frequency. Several stations broadcast mono output on FM – this makes the bandwidth used by your signal narrower, and reduces cross-channel interference. Directional antennas (such as the well-known Yagi) are also in use by a number of groups, effectively restricting signals not directed at your target community. The more time you spend on your transmission proposals, the more chance you have of getting a frequency.

There are a number of reputable transmission consultants who provide services to community radio stations and can analyse your requirements and recommend effective transmission arrangements. Neither the CMA nor Ofcom can recommend or endorse individual providers; however, Ofcom provide a list of companies who have already provided services to full-time broadcast stations here.

Ofcom has some invaluable resources here including their useful guide “10 years of community radio licensing: Advice for licence applicants“.

Should I use AM?

An option being offered to prospective licensees in affected areas by Ofcom is AM licensing. All areas except those inside the M25 have AM channels available. But there are a number of factors to take into consideration before you tick that box. In most cases, the costs of AM transmission will be several times higher than covering the equivalent area on FM. This is due, for the most part, to the larger antennas and space required–in many cases, a small field and a mast up to 20 metres high will be needed for a small local AM station. You can see an example of an AM installation used by a community radio station here.

Several community radio stations, particularly in the London area, successfully run popular, valuable services via AM. It is, however, strongly advised that if you believe you will be offered an AM licence rather than FM, you contact a reputable transmission provider and obtain costings for medium-wave transmission.

There is a big difference in the antenna requirements between FM and AM and also a correspondingly higher cost of this together with the mandatory ground system required. Ofcom still limit maximum antenna system height to 20 metres for a Community licence; the same as with AM RSLs. You will require a level area of ground similar in size, or greater to the height of the mast radius to the base of the mast – therefore you will require a square patch of land 20m x 20m.

In an ideal situation you need to locate an AM transmitter site in an area of good ground conductivity such as moist ground, near a river, lake or flood plain. This is the opposite of FM where ‘height is might’.

Here is a typical list of equipment required for AM transmission:

  1. Antenna mast plus buried ground system
  2. Transmitter
  3. Antenna Tuning Unit
  4. AM Audio Processor

Typical costs for the complete package including ground works, installation and tuning would be approximately £17,000-£20,000 at 2012 prices.

Header image: WEPN-AM Towers by Doc Searls on Flickr.

Updated by Bill Best on 3 March 2015.