Wednesday 6 May, 2009, 22:45 - BroadcastingThere is currently much ongoing debate, and some might suggest ensuing debacle, taking place to ensure that there is sufficient radio spectrum available for the London Olympic Games to be held in 2012. However, Wireless Waffle has uncovered the official Government plans for the use of the radio spectrum for the last Olympic Games held in London in 1948. Interestingly, these were before the main legislation relating to the use of the spectrum, the Wireless Telegraphy Act of 1949 were brought into power and thus predate any previous attempt to specifically control radio use in the UK.
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Let us step back to 1948... Much of London was still in ruins and rubble strewn streets were not uncommon. The budget for the games was £600,000, a figure which today would just about pay the salary of the organising committee for about a month. Food was still being rationed (indeed rationing did not end until 1954), King George VI was on the throne and Frankie Laine, Perry Como, Al Jolson and the Andrews Sisters topped the charts.
The Olympic games were televised using the EMI 405-line black and white system selected by the BBC before World War II as its preferred technology (having beaten the Baird 240 line system in trials). Only one transmitter in London was operative but an estimated 80,000 people had television receivers and were able to view the 64 hours of coverage that was broadcast. Radio coverage was also provided by the BBC and broadcast around the world using short wave.
So, with that in mind, here is the previously unpublished Government document which details usage of the spectrum. The original is not that easy to read (click on the image on the right to see it in full size) in pictorial format so here is the actual text.
Be it hereby enacted by the King's Most Excellent Majesty, by and with the advice and consent of the Lords Spiritual and Temporal, and Commons, in this present Parliament assembled, and by the commandment of the same aforementioned, as follows:-What stands out from this is:
(1) No sporting personage, radio announcer or visual televiser shall establish or use any station for wireless replication of Olympic events or install or use any apparatus for wireless tomfoolery except under the authority of a licence in that behalf granted by the Postmaster General hereinunder purported to, and any person who establishes or uses any station for wirelessness of any nature or installs or uses any apparatus for wireless purposes except under and in accordance with such a licence shall be guilty of an offence of the most serious nature which shall be punishable by flogging, booting or in any such manner as is seen fit by His Most Excellent Majesty or his appointed Government torturer or executioner.
(2) A licence granted under this section (hereafter in this Decree referred to as an olympic wireless licence or 'owl') may be issued subject to such terms, provisions and commandments as the Postmaster General may think befitting, including in particular and in peculiar in the case of a licence to establish an olympic wireless station, limitations as to the positionality and nature of the station, the purposes for which, the circumstances in which, and the persons by whom the station may be used, and the manufactory of the apparatus which may be installed or used therein therefor, and, in the case of any other licence, limitations and hampering as to the apparatus which may be installed, operated or used, and the places or locations where, the purposes for which, the circumstances in which and the person or persons by whom the apparatus may be used for such purposes thereafter.
(3) Nothing or no item in this section shall authorise or approve the inclusion, in any olympic wireless licence relating solely to apparatus not designed or adapted for emission or transmission (as opposed to reception), of any term, item or provision requiring any person to concede any form of right of entry into any private dwellinghouse, manufactory, residence or abode.
(4) Through jurisdiction of this Decree, the commandment of the use of those radio wavelengths perporting to emissions authorised herinunderafter by an olympic wireless licence shall be designated for usage and utility as per the identification and categorisation indicated in the ensuing remainder of this document.
(5) Notwithstanding these categorisations and registrations of wireless lengths subscribed to by His Majesty's Government at the International Telecommunications Union 1947 Atlantic City Plenipotentiary Conference howsoever agreed, and in cognisance of the need to control and restrict miscreant emissions of wireless stations to other wireless stations, all emissive equipment of a nature requiring a licence under this Decree should be designed, manufactured, construed and operated in ways in which other wireless stations shall be safe from explosion and other maleficent discreation.
Wavelengths of below 1 metre (over 300 Mega Cycles per second) are reserved exclusively for secret Government use. The use of these wavelenghts shall remain secret and the fact that such wavelengths exist and the fact that the use of them is secret is also a secret and should be treated accordingly.
Wavelengths of between 3 metres and 1 metre (between 100 and 300 Mega Cycles per second) may be used for televisual distribution of motion or stationary pictorial information between private wireless stations which are fixed in location and fortitude.
Wavelengths of between 10 metres and 3 metres (between 30 and 100 Mega Cycles per second) may be used for televisual distribution of motion or stationary pictorial information between a public wireless station and domestic or official wireless receptors.
Wavelengths of between 100 metres and 10 metres (between 3 and 30 Mega Cycles per second) may be used for audible distribution of broadcast material to His Majesty's Overseas Territories and other fuzzy wuzzy lands to whom the English language is comprehensible. The use of some wavelengths within this range are reserved for secret Government use, the provisions of which are secret as described above therein.
Wavelengths larger than 100 metres (below 3 Mega Cycles) may be used for audible distribution of broadcast material to the United Kingdom of this marvellousness nation hereover. Some wavelengths within this range may also be used for the exchange of message between shipping and shipping or between shipping and port establishments for the perfunction of safety and maritime information exchange and for other safety matters as may be permitted in the olympic wireless licence therein permittivised. The use of some wavelengths within this range are reserved for secret Government use, the provisions of which are secret as described above therein.
* There is a clear division between different bands and their uses - this no doubt stems from the work ongoing at the ITU at the time in establishing the international frequency registration board.
* The highest frequencies were reserved for Government use. At the time, this was largely for radar and navigation tools that had proven invaluable in the success of the war effort.
* Some bands are shared between users (though the wording of the document would imply that within any given band, frequencies were only assigned to one use or another and that no true 'sharing' as we recognise it today was authorised).
* The operation of a wireless transmitting device permitted the authorities to access your property.
* There was nothing much on television tonight and so this drivel got written.
Note: one or more of the above may be substantially or materially inaccurate.
This document (erstwhile the 'Olympic Wireless Station Commandment of Licence Neccessity and Specifity Decree, 1948') clearly sets the framework for what became the WT Act of 1949 the following year and established the groundwork for spectrum regulation in the UK that still exists today and which will continue to apply until the London Olympics of 2012 and even after that. Perhaps.
Thursday 12 March, 2009, 09:00 - LicensedHave you ever tuned into your local radio station and heard the travel news being read out from the 'eye in the sky' - a presenter checking out the traffic from an aircraft high over the area concerned? Have you ever stopped to think how that is done? Well Wireless Waffle is here to help explain it all.
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There is no denying that it would be very easy for any radio station to pretend to have a traffic plane or helicopter by playing sound effects in the background whilst the travel news was read out. However, there are some real benefits about doing it properly, not least it is possible to find out how the traffic is flowing as and when problems occur instead of waiting for listeners to phone in news (which can be unreliable) or for the local police or traffic department to let you know what's happening. But that doesn't mean that the aircraft in question can necessarily see all the problems in an area and in some cases, it is not possible to fly over certain areas due to airspace restrictions (for example, it would not make sense for a 'traffic plane' to be buzzing around a major airport, stopping commercial airliners from landing!)
What happens, therefore, is that there is someone on the ground who collates traffic information in the normal way (eg through listeners or the police) and then relays this information to the man in the aircraft. The plane (or chopper) can then visit some of the travel hotspots and see what is happening and if, along the way, they see other problems that haven't been reported, they can update the person on the ground. This means that, in general, travel news from an aircraft is more accurate and up-to-date than travel news from a regular travel studio.
From the technology perspective, there is lots of radio used (hence the Wireless Waffle interest). For starters, the pilot will be communicating with various air traffic controllers on the VHF aeronautical band (117.975 to 137.000 MHz).
Next, there is a need for the person on the ground, including the presenter in the radio studio, to be able to communicate with the presenter in the aircraft - the 'uplink'. Typically this is done via a simple VHF or UHF PMR frequency (in the UK try listening around 141.000 to 141.500 MHz and 455.000 to 455.500 MHz). As well as passing travel news to the airborne presenter, this frequency is also often used as the 'cue', providing a live feed of the station on which the travel news is to be broadcast so that the airborne presented knows when to start reading the news.
Finally there is a the link from the airborne presenter to the ground - the 'downlink'. This is usually (but not always) a slightly higher quality link than the uplink as the audio is going to be broadcast. In the UK, these links are usually at UHF (try between 467.250 and 469.900 MHz). As they are transmitted from the aircraft, despite being low power, they can often be heard over a wide area.
If the aircraft is providing travel news for a wide area, more than one up and/or downlink might be used for the different areas, depending on whether or not frequencies which can be used over a wide area are available.
In some countries, the presenter uplink and downlink are also in the aeronautical VHF band (this is the case, for example, in Malta), and the frequencies use do vary significantly between countries. If you are in an area where the local radion station has a travel plane or helicopter, why not have a tune around and see what you can find and post a comment to let us all know.
Tuesday 17 February, 2009, 20:38 - LicensedMy couple of previous posts concerning reception of BBC World Service English language programmes on short-wave in Europe led me to wondering whether there wasn't a more elegant solution to the problem of identifying which frequencies to tune to at any given time of the day.
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As it happens, every 6 months, the majority of international broadcasters get together and sit down to negotiate and co-ordinate their HF frequency usage for the coming 6 months at a conference known as the High Frequency Co-ordination Conference. The resulting plans (know as the Winter and Summer seasons) are published on the web. So with a little ingenuity and a few spare hours, Wireless Waffle proudly presents:
* The 'find a frequency in a given language, for a particular broadcaster (or both) analysis tool' *
(catchy name isn't it?!)
It works like this: You can select broadcasts in a particular language, or by a particular broadcaster in which case you will be presented with a list of transmissions currently on-air (or on-air at a time you select) today for that broadcaster together with a map of the world showing where those frequencies are being transmitted from. Using this list you can try tuning to those transmitters most local to you (or for fun those more distant) to see what you can hear.
Alternatively you can select a broadcaster AND a language in which case you will receive a list of all frequencies and times for that broadcaster in that language for today, highlighting those which are currently on-air with a map showing where those frequencies which are on-air are being broadcast from. It sounds more complicated than it is - go and try it!
To help, regions in daylight and darkness are also shown. Generally speaking if you are in an area of darkness, look for stations also in darkness which are transmitting on low frequencies (say 10 MHz - 10000 kHz - or less). If you are in an area of daylight, look for frequencies also in daylight (over 10 MHz or so).
Wednesday 21 January, 2009, 16:56 - Pirate/ClandestineVarious forums and logging sites around the web have reported that short-wave pirate station Premier Radio International was recently raided. Their transmitters and studio equipment were apparently taken. Premier Radio operated on 6265 kHz on Sunday mornings from Ireland and according to the reports the Irish spectrum regulator, ComReg, received a complaint of interference from the UK spectrum regulator Ofcom which forced them into action.
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Such a raid on pirate broadcasters is not unheard of, though a 'cease and desist' letter is often sent to the operator first to warn them that they are at risk of being 'boarded'. Short-wave stations, however, are raided much less frequently than their FM pirate counterparts who lose transmitters on a regular basis. One of the reasons for this is that it can be much more difficult to identify the location of a short-wave transmitter. The other is that interference tends to be caused outside the country in which the transmitter is located - hence the need for the collaboration between Ofcom and ComReg.
There are, however, many short-wave pirate stations that operate in and around 6200 to 6400 kHz on Sunday mornings, and many of them operate from Ireland. So the question is, what is it about the use of this frequency that Ofcom found so objectionable that they felt the need to get ComReg to take such drastic action.
The answer might lie in the particular use of frequency in that part of the radio spectrum. Frequencies from 6200 to 6525 kHz are allocated internationally to maritime mobile services. Within this range, certain spot frequencies have been set aside at an international level, through the International Telecommunications Union (ITU) Radio Regulations for certain specific uses. These frequencies are:
* 6215 (actually 6215 to 6218) kHz - allocated for distress and safety communications (analogue)
* 6268 (actually 6267.75 to 6268.25) kHz - allocated for distress and safety communications (narrow band direct printing - NBDP)
* 6312 (actually 6311.75 to 6312.25) kHz - allocated for distress and safety communications (digital selective calling - DSC)
* 6314 (actually 6313.75 to 6314.25) kHz - allocated for maritime safety information (using NBDP)
Clearly, given the safety related nature of the use of these frequencies, it makes sense to avoid them as far as possible to avoid causing interference where it really is not welcome. However, avoiding them does not just mean not transmitting on those spot frequencies. Typical AM transmitters occupy 5 kHz either side of the centre frequency on which they are transmitting. Also the spot frequencies themselves refer to transmissions with typically a 2 or 3 kHz bandwidth. So, to avoid interfering with 6215 kHz which actually uses frequencies from 6215 to 6218 kHz for example, AM transmissions on a centre frequency ranging from 6210 to 6223 kHz should be avoided. This might immediately raise the question as to why Ofcom have not complained about Italy's Mystery Radio who have used 6220 kHz for a very long time or Radio Cairo which uses 6270 kHz between 16:00 and 18:00 GMT every day, but certainly gives credence to claims that Radio Caroline's use of 6215 kHz in the late 1980s could have caused interference to safety-of-life services. With this in mind, the diagram below illustrates which frequencies within the range 6200 to 6400 kHz can be 'safely' used (in blue) without causing interference to these safety related services.
Interfering with any legitimate radio user is not to be condoned, however safety services such as these are not the best of bedfellows. I am sure that many pirates listen to the frequency they intend to use before turning their transmitters on, assuming, that is, that they have sufficient flexibility in their choice of crystals to allow them to find something relatively free. Choosing a frequency that deliberately interferes is, though, clearly a bit mad. So Radio King on 6215 kHz, Radio Malaisy on 6310 kHz and Radio Altrex who use both 6265 and 6310 kHz - be warned - you might be next to be sunk.
Whilst we're on the subject of frequencies not to choose, much of the HF spectrum is littered with transmissions that sound like this. These are NATO transmissions using their HF radio protocol known as STANAG 4285 and are therefore most definitely military in nature. Avoiding any frequency on which these noises can be heard would also seem to make sense too... otherwise it might be torpedos away.