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New and improved Freeview radiation patterns

I'm very pleased to announce that the list of the radiation patterns - the diagrams that show the power levels for each direction from a transmitter - have returned in an improved format. In addition UK Free TV now has 528 new patterns received in the last month from Ofcom under a Freedom of Information Act request.

Radiation patterns   Photograph:
Radiation patterns Photograph:
published on UK Free TV

What are radiation patterns?

All ground-based broadcast transmitter – be it for a Freeview, DAB, AM/FM radio or mobile phones – can and do broadcast their output at different levels in different directions.

The diagrams here on UK Free TV show all the known patterns.   In theory each transmitter can have a different pattern for each transmission frequency.     

This diagram shows how the Primrose Hill Freeview transmitter's coverage map and the radiation pattern for it.

Radiation pattern example

Why did you say "known patterns"?

Because, and I quote

  • disclosure of the antenna radiation patterns into the public domain could lead to these being available to foreign administrations, which would substantially weaken HM Government's negotiating position with respect to international frequency clearance;
  • a weaker negotiating position for HM Government may lead to additional cost for the broadcasters (where antenna systems have to be re-built as a result of international coordination) and lower coverage for viewers (where antenna systems have to be restricted in order to protect foreign transmissions); and
  • the BBC is required to provide coverage of its services on digital terrestrial television to a certain proportion of the population by the completion of switchover and a failure or suboptimal result from international co-ordination may harm the BBC's ability to meet this obligation.

The number of sites that we have data is limited to the data released by the BBC in 2009 – see Update on transmitter radiation patterns (BBC FOI request) – plus the new data from Ofcom.


What is the new data?

With help from Dave Lindsay, I contacted Ofcom to ask them to release the data related to the upcoming UK Digital Terrestrial Television: International Coordination Agreements

I do note that on the above-mentioned Ofcom link there is a link to "International Co-ordination Technical Parameters and Nominal Antenna Templates"  This would appear, on the surface, to provide some of the missing transmitter data.     Whilst I understand that this is co-ordination information and may represent greater coverage than the actual transmitters use, I would prefer to have some radiation pattern information with a written warning, rather than "none".  

Do the new patterns match the output?

"While you are already aware of this, I would like to emphasise that the powers and antenna templates in these files represent the upper limit of the UK’s internationally agreed rights for specific frequency assignments, and the actual antenna patterns and/or powers used by the broadcasters are often more restricted. Additionally, not all of the assignments which have been co-ordinated are currently in use." - Ofcom


New SVG format

UK Free TV was using "HTML5 canvas" to draw the radiation patterns.     However the site now uses the SVG format for the graphics.     This has the several advantages, in particular that it is now easy to embed more than one diagram in a page where necessary. 


Some examples of the new data

Where the diagrams show (CCN) this is the new "Co-ordination combined nominal template derived from International co-ordination technical agreements" data.  A pattern with a "F" prefix is for a frequency not currently used at that mast for a live TV service (F570 is 570MHz also known as UHF C33). 

New radition patterns


What next?

The site's coverage maps will be regenerated soon to include all this new data. 


Help with Television sets?
What connections are used from set top box to TV (such as SCART) ?1
If you have several TVs at home do you need separate decoders for each set or is2
Can I use a Freeview box if there is no SCART connector on my TV?3
My TV is NICAM, does that mean I have digital TV?4
Why has my widescreen TV just made everyone look fat?5
In this section
BBC Local Radio on Freeview 1
Will the World Radiocommunication Conference be the death of Freeview?2
ITV4 now on Freeview Light transmitters: retune needed for all Freeview homes3
What do the ITV changes on February 2nd 2015 at Ridge Hill and Oxford mean?4
Connected Freeview comes a step closer today5
Been missing the Digital Switchover? Good news! There is going to be another6

Wednesday, 14 October 2015
Monday, 2 November 2015
Robert Brown
5:30 PM

The Sudbury transmitter appears to be having a Freeview problem on channel 47 and HD programmes are not available even after retuning. Any info, please?

link to this
Robert Brown's 1 post GB
Tuesday, 10 November 2015
Martyn Johnson
7:28 AM

I'm a new boy, so please bear with me when I might be asking the obvious...

I see that there is a 'new' transmitter coming soon for Driffield, East Yorkshire. Does anyone know when is 'soon'?

link to this
Martyn Johnson's 1 post GB
Saturday, 25 June 2016
Richard Cooper
11:43 AM Norwich

Martyn Johnson: Hi, Martin. There doesn't appear to be any new transmitter specifically for Driffield, whether for Freeview TV or for DAB digital radio. Where did you get this info from and when did you think the Driffield transmitter was going to go live? Richard, Norwich (June 2016).

link to this
Richard Cooper's 437 posts Gold Gold GB
Richard's: Freeview map terrain plot frequency data R&TI Service digitaluk trade DAB coverage
Tuesday, 27 September 2016
David Watters
1:19 PM

I live in SE Cornwall and usually enjoy excellent Freeview from the Redruth transmitter. In the past week or so there has been much interruption to the sound and some pixillation ...... I was under the impression that those problems should have gone a long time ago? Is there a reason for this change?

link to this
David Watters's 2 posts GB
3:22 PM

David Watters: There has been no recent engineering work at Redruth in the last couple of weeks so nothing to suggest that anything has changed at the transmitter. Suggest you check out your own aerial system, start at the back of the TV and check all cables and connections then work your way back as far as you can safely access towards the aerial.

link to this
StevensOnln1's 180 posts Silver Silver GB

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