New and improved Freeview radiation patterns
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.
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
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).
What next?
The site's coverage maps will be regenerated soon to include all this new data.
7:39 PM
You really make it appear so easy with your presentation however I in finding this matter to be really one thing that I think I might by no means understand.
It kind of feels too complex and extremely large for me.
I am taking a look forward for your subsequent submit,
I'll try to get the grasp of it!
| link to this comment |
Aw, this was a really nice post. Taking the time and actual effort to create a superb
article... but what can I say... I put things off a whole lot
and don't manage to get nearly anything done.
| link to this comment |
I go to see each day a few web sites and blogs to read posts, but this webpage provides feature based posts.
| link to this comment |
10:00 PM
Great beat ! I would like to apprentice whilst you amend your web site, how can i subscribe for a weblog web site?
The account aided me a appropriate deal. I had been tiny bit familiar of
this your broadcast provided shiny clear concept
| link to this comment |
I am regular reader, how are you everybody?
This article posted at this web page is in fact good.
| link to this comment |
3:49 AM
Howdy would you mind letting me know which webhost you're utilizing?
I've loaded your blog in 3 completely different web browsers and I
must say this blog loads a lot quicker then most.
Can you suggest a good hosting provider at a honest price?
Thanks, I appreciate it!
| link to this comment |
I've been surfing online more than three hours today, yet I never found
any interesting article like yours. It is pretty worth enough
for me. In my view, if all webmasters and bloggers made good content as you did,
the net will be a lot more useful than ever before.
| link to this comment |
At this time I am ready to do my breakfast, later than having my breakfast coming again to read other news.
| link to this comment |
11:35 PM
Right here is the right webpage for anyone who wishes
to understand this topic. You know a whole lot its almost hard to argue with you (not that I really will
need to...HaHa). You certainly put a fresh spin on a topic which has been discussed for many years.
Wonderful stuff, just great!
| link to this comment |
It's in point of fact a great and helpful piece of
info. I am happy that you shared this helpful information with us.
Please stay us up to date like this. Thanks for sharing.
| link to this comment |