Ofcom Frequency Prognosis

Our Ofcom Frequency Prognosis can estimate FM frequency availability in your area.  Due to Ofcom’s strict planning rules, FM frequencies are in very short supply in the UK – in many places Ofcom say that there are no frequencies available. Even in areas where they invite applications, Ofcom have suggested that applicants ought to conduct a search for frequencies. Unfortunately that is not very simple – you cannot do it by simply tuning your radio up and down the dial – even if an FM frequency seems to be clear in your area, for a variety of reasons (which are difficult to understand for non-experts), Ofcom may not agree.  We have over 20 years experience in radio network planning and frequency planning, and we can offer advice that follows Ofcom’s guidelines.

Our “Ofcom Frequency Prognosis” is the initial stage that we use in a full detailed search.   It is similar to the first step in the process that Ofcom follow to find a frequency for a new service.  The output of this stage will give a “Prognosis” – that is to say, an indication of how likely it is that there is a frequency available for a new service in your area.  Unfortunately it is impossible to give a more definite Yes/No decision without a LOT more detailed analysis which is difficult to cost-justify before a service is launched (but might be warranted if for example you want to provide evidence for a power increase once operational)

What the Prognosis CAN do:
– Analyse every FM frequency in your area and estimate incoming interference from every licensed transmitter in the UK
– Rule-out lots of frequencies that are blatantly illegal according to Ofcom rules (including many that may be non-intuitive that would not be obvious from on-site measurements)
– Identify the “most likely” or “least worst” available frequencies in your area
– Give an experience-based, plain English opinion on the viability of your chances, including modifications to your transmitter characteristics that may help in your application. “(eg: “No Chance mate”, “Difficult”, “Maybe”, “What’s the problem” “No problem” etc!)
– If you want to go to the next stage, we can offer a detailed analysis of a particular situation to challenge Ofcom on a particular decision. (This involves a LOT of work, so to reduce the risk of a negative result, we would advise you before starting if there were no chance)

What the prognosis CANNOT Do
– Any guarantee that a frequency we suggest is suitable is actually acceptable to Ofcom. They seem to apply additional criteria that we, (and you) do not know about

The output looks like this:

Ofcom Frequency Prognosis

The system uses the latest available Ofcom database.  It takes account of every UK licensed transmitter on every frequency.  It calulates bearing, includes affect of directional antenna systems and factors in transmitter power, height and distance.   It then adds all the interfering signals into the display above.   Next it applies Ofcom’s rules such as Co and adjacent 1-4 protection ratios and 10.6-10.8MHz image channel restrictions.

As you can see, this approach quickly rules-out many frequencies – some of them will be non-intuitive that you might previously have thought were clear.   We will give a “plain English” assessment of the result and provide you with the “least worst” frequencies that might be available, and our experience-based opinion on your chances of Ofcom saying there is a frequency available.

In the ideal world, this short-list of frequencies would be analysed in detail in order to prove that all possible interference modes are respected, and to generate maps that prove this.  However that entails many weeks detailed work and is not really economical to offer as a service unless you have deep pockets!   This detailed analysis is most suitable in situations after a known frequency has been allocated – eg: to discuss with Ofcom about changes such as power, site location, antenna pattern etc.

In contrast to full detailed analysis, this Ofcom Frequency Prognosis is cost-effective and at least provides some visibility of the chances of a frequency being available (and ruling out ones that are definitely not).

Ofcom Frequency prognosis – £149



Unfortunately in FM allocation decisions, Ofcom are judge and jury.   Our Ofcom Frequency Prognosis product is a tool to estimate the situation according to Ofcom’s published technical criteria.  However it is not perfect and we cannot take into account other arbritary policies that they sometimes invoke to reject applications.  It is best used to rule-out frequencies that are definitely not suitable, or to discover whether your £600 application fee might be a waste of money if no frequencies are available.