Wireless Waffle - A whole spectrum of radio related rubbish
Ofcom Sanctions Free Radiosignal strength
Thursday 24 September, 2009, 14:12 - Spectrum Management
Posted by Administrator
Well who would have thought it! According to many pages on the subject across the internet, hang gliders have a special arrangement with Ofcom to allow them easy access to various radio frequencies without needing a licence! Yes, apparently a chap called Rod Buck, the then radio officer of the British Hang Gliding and Parachute Association (BHPA) reached an 'agreement' with the Radiocommunications Agency some years ago (must have been quite some years as the Agency was disbanded in 2003) that they could use a set of radio frequencies for air to air and air to ground communications and as long as they stuck to them the Agency would 'turn a blind eye'.

What are these frequencies? 143.750 to 143.950 MHz in 25 kHz steps. If you don't believe me, take a look here. The top of this frequency range, 143.950 MHz, is the unofficial calling channel and from the Wireless Waffle HQ it is alive most days with chitter chatter from enthusiasts dodging in and out of planes, talking about the weather and checking out possible landing sites.

hang glider interferenceNow it's true to say that the use of radio when airborne presents lots of safety benefits, and it's clear from much of the communication that goes on that the guys dipping and diving around are helping each other out. But there are official frequencies for this purpose. The problem with these official frequencies is that the equipment required to use them is expensive and a licence must be obtained (albeit at just £75 per year), whereas the unofficial frequencies come at no charge and equipment can be had from certain on-line auction sites for less than £50 all sold.

Notwithstanding the safety benefits though, the use of these frequencies is, to all intents and purposes, illegal. There is plenty of illegal frequency usage around, from pirate broadcasters to Brazilian satellite hijackers but in all these cases, if the user suffers from interference due to a legitimate user then there is really no harm done as the user's use of radio is not in any way safety related (this is not to say that the legitimate user does not suffer, just that the suffering of the illegitimate user is largely inconsequential). In the case of hang gliders, however, the situation is very different. If they suffer from interference then the implication is that air safety (and possibly even safety of life) is compromised which is quite a big deal when you think about it.

One forum post states:
These frequencies are not currently used or allocated elsewhere, so you won't interfere with anyone else.

radiation causes mutationThat's not strictly true. The frequencies are actually allocated, in the UK, for 'Land Mobile' services, though at an international (ITU) level they are allocated for Off-Route (eg Military) Aeronautical Mobile use. According to the UK frequency allocation table (FAT) the band 143 to 144 MHz is set-aside for emergency service use. In terms of actual frequencies assignments, it is fair to say that they do seem to be few and far between in this frequency range though there is some evidence to suggest that the US Air Force as well as the Metropolitan Police in London use the frequencies, and that they may well be some of the emptier frequencies being considered to alleviate demand for spectrum during the 2012 London Olympics.

Anyway, given the agreement that these users are supposed to have have reached with the regulatory authorities, we here at Wireless Waffle feel that there is plenty of scope to apply the same approach to some other areas of regulation too.

colourful wiring* Allow electric cars to use either side of the road, as long as they keep their lights turned off and aren't painted a bright colour.
* Let children cross railway lines (including level crossings) at any time if they are standing near nettles, or being chased by bees, wasps or other stingy things.
* Permit short people to set fire to whatever they like but only if the device used to start the fire can be hidden if anyone approaches.
* Encourage demolition crews to trigger explosions more straightforwardly by simply shining a green torch at the detonator.
* Allow mains wiring in all new houses to be any colour the electricial likes, as long as it fits with the painter's colour scheme.
* Make sure that all knives sold to people weighing under 154 lb (70 kg), of whatever age, are longer than 18 inches and lethally sharp.
* Inform aircraft to keep from crashing into each other by communicating using semaphore and old tin-cans.

Oh, hang on, apparently the Radiocommunications Agency have secretly agreed the last of these with the Civil Aviation Authority. We await the small print of the manifestos of the various political parties at the next election with great interest to see if any other of our other ideas come to fruition or what else the good folk of the UK will be allowed to get away with. Actually, it's pretty clear why aircraft and hang gliders are allowed to act illegaly and not get prosecuted: they are above the law!
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High Frequency Funsignal strength
Friday 11 September, 2009, 08:08 - Spectrum Management
Posted by Administrator
It seems there is nothing that visitors to the Wireless Waffle web-site like better than a list of interesting radio frequencies to have a go at listening to. Previous articles in subjects such as frequencies for London airports, tuning into US military satellites and unusual UHF activity are some of the more popular pages according to the various logs kept by our web-server.

So with that in mind, here are a few 'interesting' HF (short-wave) frequencies that might be worth a listen. Any frequency where recent activity that is most likely caused by the indicated source has been noted (either by Wireless Waffle or on other useful sources) is marked with an asterisk.

Test and Development Frequencies

2806, 5750, 7556, 9071, 10438, 11117, 16014, 18990, 20990, 24135 and 26218 kHz

According to the 2007 UK frequency allocation table (Annex I) these frequencies are the preferred HF frequencies for test and development use (interestingly they have disappeared in the 2008 version. Anyone with a test and development licence is allowed to use powers of up to 100 Watts on these frequencies with a bandwidth of up to 25 kHz. Some years ago, whilst working for a manufacturer of military HF radio equipment, tests of the equipment 'on-air' were witnessed by the Wireless Waffle team using one of the rare 'G9***' UK callsign (the exact call letters of which have been forgotten) and it's fairly certain that these were the frequencies that were used. May be worth a tune around to see what else goes on here.

air cadet logoAir Cadet Frequencies

2368, 2490, 2848.5, 3236*, 3306, 3343, 3678, 3715 and 3752 kHz
(Channel designations Lima 1 through Lima 9 respectively)

5245, 4925 and 5088 kHz
(Channel designations November 1 through November 3)

5770*, 5795, 7740, 6775 and 7721 kHz
(Channel designations Hotel 1 and 2, and 5 through 7)

8120, 13545, 10843.5, 14500, 13445 and 13965 kHz
(Channel designations Oscar 1 through 6)

Air cadets are permitted to use these frequencies with powers of up to 350 Watts (a few are restricted to 100 Watts) for communication. Voice and data can both be used (some channels are data only). Checking a few of the channels revealed occasional strong blasts of data. Note that some of the Lima channels are in the 80 metre amateur band!

sea cadet logoSea Cadet Frequencies

2122.5, 2695, 3660, 6805, 6875, 6992.5* and 8187.5 kHz
(Channel designations SCO01, 02 and 11 to 15)

Sea cadets are permitted to use between 25 and 100 Watts on these frequencies. Again note the channel (in this case 3660 kHz) in the middle of the 80 meter amateur radio band.

army cadet logoArmy Cadet Frequencies

2275*, 2415*, 2770*, 3850*, 3865*, 4920, 4922.5*, 4955, 5330, 5345, 6915, 7710 and 7753 kHz

Note that for these frequencies (and those for the other cadet forces), the listed frequencies are supposed to represent the centre of the channel. As such, if listening to an SSB signal, it is necessary to tune 2 kHz lower than the listed frequency. So if you want to listen to 5330 kHz (supposedly a common calling channel for the army cadets, tune initially to 5328 kHz). Also, operation is allowed within 5 kHz of these frequencies so listening plus or minus a bit may yield something interesting.

The sea cadet and RAF cadet frequencies are taken from official publications, whereas the army cadet frequencies are based on an extensive search and cross-check of internet sources but these may not be as accurate as the earlier two!

raf strike command logoRAF Flight Watch (TASCOMM)

4742*, 5702*, 9031*, 11247, 13257 and 18018 kHz

TASCOMM is part of the Defence High Frequency Communication Service (DHFCS) which is managed from the network control centre at Forest Moor. They are the frequencies used by the RAF. DHFCS also managed the HF frequencies for the Army and Navy too. Transmitters are often high power and are located both in the UK and at some overseas military bases (such as Cyprus and Ascension). The net controller uses the callsign 'XSS'.

Note that those frequencies market with an asterisk (*) are ones on which either activity has recently (ie in the past 5 years) been reported somewhere on-line, or where the Wireless Waffle receiver has noted activity.

Now it would be good to try and make something of this list and identify lots of 'secret military HF bands' where there were hotspots of activity, however no such hotspots really emerge, instead there are a few warm damp patches which might be worth exploring. Where there is any commonality between these frequencies it is in the ranges {the ITU allocation to these bands is shown in curly brackets}:
  • 3660 - 3865 kHz (6 assignments) {Mobile/Land Mobile};
  • 4742 - 5088 kHz (6 assignments) {Mobile/Land Mobile/Aeronautical Mobile (OR)};
  • 5702 - 5795 kHz (4 assignments) {Land Mobile/Aeronautical Mobile (OR)};
  • 6775 - 6992.5 kHz (5 assignments) {Mobile};
  • 7556 - 7753 kHz (5 assignments) {Mobile};
  • 8120 - 8187.5 kHz (2 assignments which is not exactly conclusive) {Maritime Mobile}; and
  • 9031 - 9071 kHz (again 2 assignments) {Aeronautical Mobile/Fixed}.
up holding the sanc tit yIn almost all of these cases, the frequencies concerned fall within the 'Mobile', 'Land Mobile', in the case of TASCOMM, in the 'Aeronautical mobile (OR)' and in the case of the Sea Cadets the 'Maritime Mobile' services of the ITU and as such are almost exactly where you would expect to find them had you decided to look there in the first place. The only oddity is the test and development frequency at 9071 kHz which is in a 'Fixed' band, but then again, this is not a military frequency and it's quite possible that someone somewhere might want to test an HF fixed link.

So, sadly, no secret service special frequency bands have been identified but at least it seems that the United Kingdom's armed forces are doing their bit to uphold the sanctity of the ITU frequency allocation table.
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Super Signal Holiday HF Antenna Apparelsignal strength
Friday 7 August, 2009, 09:31 - Radio Randomness
Posted by Administrator
August is almost universally, the world over, the month when schools are out and people head off on their well deserved and hard earned summer vacations. However, here at Wireless Waffle have received a number of worried e-mails from radio lovers who are concerned that whilst they are away on holiday they will not be able to enjoy listening to their favourite short-wave radio transmissions, whether the news on their favourite international broadcaster or the messages from their friendly neighbourhood secret service spy numbers station.

harrier hf antennaBeing equally worried, we have been searching for an answer to this annual seasonal dilemma and think that we have stumbled across the perfect solution. Study, if you will, the picture on the right. This is one of the Royal Air Force's fabled Harrier Jump Jets. If you look closely you will notice that strung from the rear tail-fin to a point just behind the pilot's cabin on the fuselage is a thin wire antenna. Normally this wire is too thin to be seen in such a small picture but we have enhanced it to make it more visible. This is an HF (a.k.a. short-wave) antenna which is used for air to ground communication. Similarly strung aerials can be found on civil aircraft and on many warships, stretching from the top of the radar tower to somewhere close to the deck.

These antennas actually work quite well and though a decent antenna tuner is needed to provide a good match at the range of frequencies on which military HF communications normally take place, they produce relatively good results because:

* the sloping nature of the antenna offers a degree of mixed polarisation, increasing received and transmitted signal strengths compared to a horizontal or vertical antenna (as with an inverted-V antenna)
* the position of the antenna above the body of the aircraft means that the aircraft acts as a reflector, directing signals upwards towards the ionosphere
* the antenna can be reconfigured to use part of the aircraft body to form a loop antenna where this is more effective

ideal antenna mountIn a flash of inspiration, the Wireless Waffle team realised that a very similar antenna could be constructed and tied to a tree on a Caribbean island. However, though a practical and realisable solution, this idea failed to address some of the main difficulties in a number of very important ways:

1. not all holiday makers carry a roll of suitable wire
2. not all Caribbean beaches have a suitable tree on which to string an antenna
3. where trees exist, the holiday makers with wire may not be able to climb the tree
4. not all summer holidays take place in the Caribbean

Deflated but still keen to find a way forward, the team decanted to the local travel agency to study holiday brochures for alternative antenna mounts. Whilst wandering down the high street, one of the team happened to glance into a sports shop and inspiration struck: what if a suitable antenna could be built into an item of beach apparel such that it went on hoilday with the person concerned without needing to carry wires or tree climbing apparatus.

bikini hf antennaAfter much development, we are therefore very proud to present the 'Wireless Waffle Super Signal Holiday HF Antenna Apparel' (we are still working on a snappier title). In the same vein as the aircraft HF antenna, the wire is strung between the tail-fin of the wearer and a point below the fuselage where their head joins their body. As you will see, it bears a remarkable similarity to the one mounted on the Harrier Jump Jet.

Our thorough tests have shown that the antenna works exceptionally well and is very good at picking up signals. We managed to receive a strong Voice from America (saying something about a drink at the bar), whistles from the military and several numbers. Encouraged by these results, we are currently in discussion with a major radio manufacturer about the sales opportunities for our device and the outlook seems quite positive. Keep an eye open on beaches in your area and please send us pictures of any devices you find in use. If we receive enough we'll post a gallery so that others can see how to assure maximum performance.
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Come Spy With Mesignal strength
Thursday 23 July, 2009, 08:00 - Radio Randomness
Posted by Administrator
It may come as a surprise to the more ICT literate that in this day and age, short-wave radio is still being used for secret communications from various security organisations to their field agents. No encrypted e-mails or messages hidden on web-pages, no images hidden in jpeg files or microdots or secret domain extensions. Nope, many agencies transmit messages over short-wave using standard AM modulation which can be received on every day, off-the-shelf radios.

You may have even heard these transmissions and not known what they were. Known as 'numbers stations', the transmissions consist of a series of numbers being read out in a mechanical fashion, often repeated several times and often preceded by a specific piece of music. The numbers are usually in English, German, Spanish, Arabic or a slavic language (eg Russian) which may give an indication of the source of the signals (though it is known, for example, that some of the transmissions in English are from the Israeli secret service, Mossad).

Unlike most short-wave transmissions, the source of these signals is often elusive and as such, receiving any kind of acknowledgement of their reception is nigh on impossible. This does not stop, though, a band of enthusiasts monitoring and recording these signals and exchanging information between likeminded individuals. Probably the largest such group is known as 'Enigma 2000' who publish a regular monthly newsletter which can, thankfully, be obtained for those who are interested without the need to join the group (which has strict membership criteria) from the Numbers and Oddities site.

A typical numbers transmission consists of the following elements:

* A piece of music or other 'tuning signal' to enable the transmissions to be easily identified
* A set of numbers or letters to identify which agent the message is addressed to
* A message identifier (so that the agent knows whether this is a new message or one already received)
* The encryption key (page in the one time pad - see below)
* The message itself

It might end up looking something like this:

131 1 445 137
40169 89117 20298 35013 41171 11312 63536 93396 46878 16093
29358 33200 82800 62186 11396 84614 82364 31802 82184 13856
76542 20793 72496 02687 56367 66812 18736 23959 33356 29647
21272 04668 08563 59079 71771 45056 59223 74346 70438 99776
45393 22483 06897 74008 87564 11186 28378 86003 16942 77970
000 000


one time padSo how does the agent decode this message? It is suggested by those in the know, that they are unravelled using something called a 'one time pad'. The agent looks up the page in his book of one time pads which has a set of figures which allows the numbers to be translated into letters or words to decode the message. Once decoded, the page in the pad is burnt, eaten or otherwise destroyed. Without access to the pad, the message cannot be decrypted (eg by opposing security agencies) which makes it singularly secure. If the agent is captured and his pad falls into enemy hands, as long as the HQ is aware, they can stop sending messages to that agent. As each agent's pads are different, they cannot decode messages sent to other agents.

That such messaging systems are still used is, perhaps, not that surprising. That they should still rely on short-wave radio to send these messages to agents perhaps is. An e-mail could do the same job much more quickly and for less money. The advantage, however, of short-wave is that no specialist equipment is required to get hold of the message (short-wave radios are available in markets and bazaars around the world for a handful of dollars) and has the real advantage that the location and identity of the agent are not revealed by the transmission as they might be if an e-mail was traced by the authorities.

ukranian spy neighbourHearing these transmissions is relatively easy. Mossad in particular seems to pepper the airwaves with transmissions, usually in the hours of darkness in Europe when local propagation is more straightforward (and presumably when agents are not out doing their day job!) Common frequencies include (though these change seasonally) 3840, 4270, 4880, 5435, 6840 and 9130 kHz from around 1800 GMT to at least 2000 GMT and later.

So, if you catch your Ukranian neighbour sunning herself in the garden whilst listening to seemingly random sets of numbers being read out on the radio, thanks to Wireless Waffle you now know exactly what is going on!
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