Wireless Waffle - A whole spectrum of radio related rubbish
Know Thy Neighboursignal strength
Wednesday 21 January, 2009, 16:56 - Pirate/Clandestine
Posted by Administrator
the pirate keyVarious 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.

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.

pirate going downThe 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.

6200 6400 khz

ofcom closing inInterfering 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.
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Duel-Castingsignal strength
Thursday 13 March, 2008, 08:41 - Pirate/Clandestine
Posted by Administrator
100 watt pirate transmitterFinding a frequency must be one of the most fraught tasks for any prospective London pirate radio operators. The band is now so crammed with stations that there are next to no gaps anywhere. The problem is not made any easier by the BBC using lots of frequencies to infill coverage of its local stations; nor by the new wave of community stations taking to the air. Now don't get me wrong, BBC, commercial and community radio stations have a licence and are authorised and legitimate users of the FM band and as such should be respected, and nothing hereinafter should be in any way taken as non-recognition of that important fact. But the fact also remains that pirate radio stations exist and are likely to continue to exist until technology renders them irrelevant and that finding a frequency that doesn't cause interference to these legitimate users, which is a goal to be aimed for if both legal and illegal stations are to co-exist, is nigh-on impossible.

some pirates betterSince 2000 Ofcom (and its predecessor the Radiocommunications Agency) have been aware (through an oft overlooked study that examined the re-planning of the FM band) that there are small pockets of the FM band that could be used for low-power, limited geographical coverage transmitters in and around London, and it is the results of this study that are, to a large extent, enabling the licensing of the community stations. It's also interesting to note that many of these community stations are using frequencies that were esrtwhile used by pirates. Question: If they can now be used legally for such services without causing interference, can it be completely true that when being used illegally by pirates that the interference they cause was really so bad? Well the power of the community stations is typically less than 100 Watts and they are specifically located in areas where the frequencies they use will not cause interference, whereas the pirates on the same frequencies were often using 250 Watts or more in an attempt to cover a much wider, or a different, area. So it is quite likely that the pirates did cause interference in some areas, but clearly not in others.

walk the plankOne of the interesting side-effects of this use of previous 'pirate' frequencies by the new community stations is that the pirates have been forced to take action to try and maintain their coverage and listenership without causing (too many) problems to the new stations. Blasting several hundred Watts over the top of a new community stations is the perfect recipe to get busted. Hats off, therefore, to Passion FM who, having been forced off their long-time frequency of 91.8 MHz by community station Hayes FM in West London, have taken to using two different frequencies, with directional antennas, to protect Hayes FM yet maintain their service area. Passion can now be found in East London on 91.8 MHz and in West London on 97.9 MHz, thereby making an effort not to interfere with Hayes FM at the expense of having two lots of transmitters to replace each time they are taken off-air.

rubbish pirateWest Londoners Point Blank FM also deserve a mention. They are broadcasting to South West London on 103.6 MHz (and thus avoiding Life FM in Harlesden, North London and TGR Sound on 103.7 MHz in South East London) and to Central London on 90.2 MHz, having moved off 108.0 MHz where they used to cause undue interference to Radio Jackie on 107.8 MHz. 108.0 is now used by Unknown FM whose service area, being further East causes fewer problems to Jackie. Both Passion FM and Point Blank FM use the correct RDS Alternative Frequency ('AF') flag so that listeners driving around London will automatically be re-tuned to the clearest frequency - smart! Freeze FM are also 'dual-casting' on 92.7 and 99.5 MHz - it's not clear why but possibly one of the community stations yet to come on-air (Radio Ummah and Irish FM) may use a frequency near 92.7.

Pirates are often accused of not caring about interference to other stations, but the actions of these stations would tend to suggest that they do take some care - not least, perhaps, to protect themselves from an excessive number of raids from the authorities.

For the record, other pirate/community frequency clashes that will no doubt resolve themselves in the end are Westside FM (Southhall, West London) and Select-UK (Rotherhithe, South London), both on 89.6 MHz, Nu-Sound (Forest Gate, East London) and Powerjam (Battersea, South London) on 92.0 MHz, and Voice of Africa (Newham, East London) and Tempo on 94.3 and 94.4 MHz respectively.
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Roof Raiders II - The Council of Lifesignal strength
Wednesday 27 February, 2008, 09:49 - Pirate/Clandestine
Posted by Administrator
lara croft roof raiderIt seems as if Ofcom has been up to its tricks again. On February 19th they announced that they had conducted another large-scale raid on London's pirate radio stations similar to one it conducted in 2005, however this time it was in conjunction with the local council authorities whose buildings are often the home of the pirates' transmitters. 22 transmitters were seized and 3 people were arrested.

I won't repeat the musings I made last time this happened concerning the probability of pirates causing the kind of wide-spread radio interference they are accused of. The latest news release from Ofcom actually plays down the interference aspects compared to their previous press release, and now plays up the difficulties and dangers that councils face due to the damage caused to property when pirates break into buildings to install their equipment. There can be no doubt that such damage does get caused when pirates break into lift-shafts and onto the rooves of blocks of flats which, if anything, only serves to highlight the desperation that such stations face and their determination to bring the kind of music they play to their audiences. Clearly mainstream radio is not catering for a whole swathe of society.

spondwick by ormWhether or not they are working in cahoots or not, it seems that the BBC is intent on reducing the number of frequencies which might otherwise be useful to community (or pirate!) radio broadcasting. It has recently expanded coverage of 'Three Counties Radio (3CR) by adding relay stations in East Herts, South Herts and High Wycombe. However unlike the majority of other BBC local radio stations, these relays use frequencies in the bands usually used by the BBC for relays of national radio stations (90.4, 92.1 and 98.0 MHz respectively). Now the BBC are quite at liberty to use their own spectrum as they see fit, but this move away from a logically planned system to something more flexible surely suggests that a similarly flexible approach might be taken on a wider basis to allow for frequencies for more, new, innovative radio stations rather than just repeating existing ones. These three frequencies could have been used for new commercial or community stations in these areas. It's not that BBC coverage did not exist there before, it's just that it wasn't quite as good as the BBC had hoped.

I still maintain that it's quite possible that pirate stations can (and do) cause interference to legitimate users of the radio spectrum. It's clear, though, that Ofcom is only making small inroads into solving the problem and that other parties are doing nothing to assist. There has to be a long-term solution to the problem if it is ever to be solved and one commentator has suggested that when radio broadcasters have moved over to digital broadcasting (whether DAB, DRM, or something else), some of the 'digital dividend' that results should be given to low power, lightly licensed, radio broadcasting. Sounds like an eminently good idea to me.
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How to listen to UFOssignal strength
Friday 31 August, 2007, 10:48 - Pirate/Clandestine
Posted by Administrator
Since the late 1990's rumours have abounded that it was possible to hack into American military satellites and use them for wide area communication. The satellites, originally the 'FleetSatCom' newtork (often abbreviated to FLTSATCOM) use basic FM modulation and have uplinks in the area of 300 MHz and downlinks in the area of 260 MHz. Stories went that tuning in to the downlinks it was possible to hear illegal pirates, from Brazil in particular, who were usurping these US military satellites to use for wide-area communications. It was also said that 'Smile 93.9 FM' (rumoured to be from Manila) was using one of the channels as a studio to transmitter link and could often be heard on the downlink frequency of 269.950 MHz.

This seemed a little far fetched and unbelievable: How could one of the world's most super-sophisticated armed forces allow their multi-million dollar military hardware be taken control of by such an unsophisticated enemy armed with nothing more than a simple UHF FM transmitter? Using a simple VHF/UHF receiver and a bog standard roof mounted VHF/UHF antenna, I set out to try and debunk the myth.

Within seconds I was listening to a conversation between two likely sounding chaps on a frequency of 255.550 MHz. Next I stumbled across more voice traffic (definitely in Portuguese, the language spoken in Brazil) on 258.650 MHz. And before long I found more voice traffic on 253.850 MHz. Intrigued that this long reported phenomena was still in evidence I did a bit of digging on the internet to find out more.

The original FleetSatCom satellites which were launched in the late 1970's and early 1980's are no longer operational. They were initially replaced by satellites known as Leased Satellites (Leasat) which have also since been replaced by the UHF Follow-On series of satellites, ironically acronymised as UFO. The UFO satellites continue to provide the same communications capabilities as the earlier ones but with somewhat higher transmitter powers, making reception of them fairly straightforward.

A bit more digging uncovered military standard MIL-STD-188-181A which describes the interface specification for the satellites (i.e. the technical requirements for equipment used to access them) and in it we find a list of the uplink and downlink frequencies used. All the frequencies I could hear are in group 'Charlie', now known as group 'Quebec' (Q) on the UFO satellites. Group Q comprises the following 25 kHz wide downlink frequencies (uplink frequencies are 41 MHz higher):

ufo fltsatcomQ1 250.650 MHz (Fleet Broadcast)
Q2 252.150 MHz (Navy Channels)
Q3 253.850 MHz
Q4 255.550 MHz
Q5 257.150 MHz
Q6 258.650 MHz
Q7 265.550 MHz
Q8 267.050 MHz
Q9 269.450 MHz
Q10 269.950 MHz
Q11 260.625 MHz (DoD Channels)
Q12 260.725 MHz
Q13 262.125 MHz
Q14 262.225 MHz
Q15 262.325 MHz
Q16 262.425 MHz
Q17 263.825 MHz
Q18 263.925 MHz

So far, I have heard sporadic voice traffic on channels Q2, Q3, Q4, Q5 and Q6 and something, albeit rather weak on Q7. It seems as if the satellite I am hearing is UFO-7 which is situated over the Atlantic. But is this traffic really pirates using the satellites on purpose, or is it something else? Surely there is no longer the need, in Brazil or other countries, to use US military satellites for communications, especially now that mobile phones and mobile coverage are virtually ubiquitous?

A quick look at the Brazilian frequency allocation table, the Plano de Destinação de Faixas de Freqüência, shows us that the frequency range 270 - 326.8 MHz is assigned to the fixed and mobile service, and in particular to public correspondence. So the frequencies are quite legally in use for various communication services; could it be that they are being relayed by the satellite is incidental and a result of the fact that the uplink frequencies are used differently in different parts of the world? So maybe there are no Brazilian pirate radio mafia trying to jam US military satellites after all then? What a shame, it seemed like such a good story.
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