# Numbers Stations



## JoanDrake (Jul 1, 2015)

This is something I've never heard of

http://www.bbc.com/news/magazine-24910397

but it surely sounds intriguing. Have there been stories on it, of any length?


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## Ray McCarthy (Jul 1, 2015)

Yes, but not at any length.

I first head them about 1966. They still exist.
The point is that an ordinary domestic world band radio (like the €10 model Tesco sells today) can pick them up. The spy uses a one time code pad on rice paper or bubble gum to decode the message.

So they can't be decoded, one time pad random code is unbreakable.

There was a report of arrests in USA a long time ago in USA and domestic shortwave radio and bubble gum codes mentioned.

All the major powers seem to run Numbers Stations. I have a recording or two somewhere.



> What is suddenly heard on a shortwave receiving station is a 10-minute message in Morse code.


Most are spoken. Real morse needs an SSB receiver, which only Radio Amateurs would have outside of professional usage. Also today only some Radio Amateurs (Hams) use Morse.

That 2014 article is a recycled older one. There was a program on it on BBC R4 called "The Lincolnshire poacher" I have a mp3 of it too.


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## Toby Frost (Jul 1, 2015)

I find these fascinating in the same way as the pictures in The Dumas Club: not so much for the tech, but because they prompt the question "Who is on the other end of this?" A numbers broadcast could be a very interesting way of opening an SF novel. Perhaps the right broadcast prompts an unexpected response in a machine?


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## Ray McCarthy (Jul 1, 2015)

The original program and web articles were in 2005 
http://genome.ch.bbc.co.uk/a235eada15ab445b8db901587acb7ae3
*
See especially*
http://www.simonmason.karoo.net/page485.htm

http://www.numbers-stations.com/

http://www.simonmason.karoo.net/page30.html

http://priyom.org/


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## JoanDrake (Jul 2, 2015)

The story reminded me just slightly of the part in Tim Powers WWII novel DECLARE where his protagonist and his gf use magic to aid in sending radio messages to the Allies from occupied France. I wonder how magic might be worked into this idea.


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## J Riff (Jul 2, 2015)

I have a base station shortwave that I found, it works... but there's never anything happening. No cabs, cops, ham operators , the airwaves are basically deserted.


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## Ray McCarthy (Jul 2, 2015)

J Riff said:


> the airwaves are basically deserted.


No, plenty.
a) What bands? Is it CB?
b) for shortwave you will get stations on a whip, but not as many as long wire.
c) Depending on time of day and conditions you listen on different bands.

Cabs and Cops haven't been on Shortwave since 1940s, probably!
Cops use Encrypted Digital (Tetra on low UHF in UK and Ireland, other systems in USA). Before that they used VHF-FM, not shortwave.  Cabs can be low VHF, high VHF or Low UHF, FM or using Digital.

You need SSB on Shortwave, or data decoding via laptop for hams. They are very specific bands.

"base station" isn't how short wave sets are described It's very rare for much Shortwave activity above 20MHz. CB is 26.5MHz to 27.5MHz depending on country. Usually on Channels. But there are three main schemes.

@J Riff
I can give you more detail on what when and where. I'd need to know the country and if a large one, the state/province /territory.


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## Ray McCarthy (Jul 2, 2015)

JoanDrake said:


> I wonder how magic might be worked into this idea.


Radio is Magic ... It's just you are familar with it and they pretend there is a rational explanation. They have the rules all worked out, but then there is Sporadic E, Trop, MUF, the ionisphere (but why some days  it works and others it doesn't), Meteor scatter.


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## J Riff (Jul 3, 2015)

Well I will have to dig it out and plug it in. The antenna is missing but I have some other ones may work... a powered one.... but the connector..(tbc)


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## Ray McCarthy (Jul 3, 2015)

For shortwave some wire (3m to 20m long) works better than a built in telescopic whip. You sure it's not a desktop scanner? A short wave radio does at least 6MHz to 20MHz, often more, and will have MW / Broadcast too. If for European market rather than Americas has Long Wave also.
A Scanner usually does 26MHz to 1300MHz (old ones only up to 80MHz). Though I have three sets that can scan that cover 100kHz to 30MHz and various other bands.


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## Venusian Broon (Jul 4, 2015)

@Ray McCarthy Question for you - I have childhood memories of picking up radio transmission on valve amplifiers - music amplifiers for guitars/keyboards - specifically when they were being turned off. That's possible right? I'm not mis-remembering or imagining that?!?

I'd test it out but I've only got a small transistor practice amp and I'm pretty sure these things don't pick up curious radio emissions.


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## HareBrain (Jul 4, 2015)

JoanDrake said:


> The story reminded me just slightly of the part in Tim Powers WWII novel DECLARE where his protagonist and his gf use magic to aid in sending radio messages to the Allies from occupied France. I wonder how magic might be worked into this idea.



Yes -- I thought the same. And he did quite nicely connect his djinn with the radio thing, as I recall.


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## Ray McCarthy (Jul 4, 2015)

Venusian Broon said:


> I have childhood memories of picking up radio transmission on valve amplifiers - music amplifiers for guitars/keyboards


Lots of amps, especially the transportable mains record players, transistor and valve did pick up a passing taxi, ambulance, police or fire engine.

Nothing much to do with it being turned off, though I guess some valve amps might have had briefly "anode bend" detection. But I've been using, repairing and building valve amps from mid 1960s and I don't remember any worse at turn off. I added RF blocking filters (often a small coil and a capacitor) to many record players and amps in 1970s to cure them.

The Mobile 2 way radio users have moved to higher frequencies and also often digital which is one reason it's rarer. Also many amps now have explicit audio band low pass filter now because many CD players, phones, MP3 players etc output some RF (or 192kHz oversampling) on the audio out. That makes it rarer too.

But most powered PC speakers, powered phone speaker docks and TV sound bars are rubbish. You'll notice them buzz and warble loudly if phone is near, sometimes without a call, as occasionally the phone tells the base station where it is. If you don't want tracked, take the battery out. The phone HAS to occasionally listen for base and call it or else calling a mobile would need the call to go out on EVERY base station everywhere. This is why people can still phone you when you are in Germany or France on a phone normally in Ireland or England.

Your average 1950s table radio has a better loudspeaker than most phone docks, TV speakers, sound bars and small home theatre boxes. Plastic is rubbish for a speaker case. Decent bass is impossible on a small cabinet and as speaker size goes below 6" bass vanishes. A 4" speaker in an MDF box about  5" x 9" x 7" internal is about minimum. There is no flat screen TV at all with a usable built in speaker. The "bass" on modern small speakers is just a resonant thumping.

I have a licensed transmitter, on some bands it will come through clearly on PC speakers on the other side of the house.


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## Venusian Broon (Jul 4, 2015)

Ray McCarthy said:


> Lots of amps, especially the transportable mains record players, transistor and valve did pick up a passing taxi, ambulance, police or fire engine.
> 
> Nothing much to do with it being turned off, though I guess some valve amps might have had briefly "anode bend" detection. But I've been using, repairing and building valve amps from mid 1960s and I don't remember any worse at turn off. I added RF blocking filters (often a small coil and a capacitor) to many record players and amps in 1970s to cure them.



Well, they wouldn't suddenly pick up transmissions when you were actually using them - a'la Spinal Tap - only in the moments when the power was switched off and everything exponentially powered down, you could distinctively hear it as the amp valve (I assume) drained or discharged in some manner. Possibly it was an artefact of a particular design???

I had a transistor amp for years, so I never got any more of these 'ghost' signals on my musical equipment post 1986, which I assumed was because they had this fancy new electronics inside it rather than a specialised light bulb...(although I prefer the nice warm sound of the fancy light bulb, but hey, not really too much into generating music these days.)


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## Ray McCarthy (Jul 4, 2015)

Venusian Broon said:


> only in the moments when the power was switched off and everything exponentially powered down, you could distinctively hear it


I can theorise as to how that works, but certainly never heard that specific effect on any of the many 1950s valve PA or fender, marshal etc.
If you remembered the make and model I can explain it. But it's obviously rarer than the pick up during ordinary use of old style analogue low band VHF mobile vehicles passing (which was very common late 1950s to 1980s or even 1990s).



Venusian Broon said:


> Spinal Tap


Well, that was a mockumentary, though they may have formed a real band and toured after the film.

However nothing to do with Shortwave Radio.


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## Venusian Broon (Jul 4, 2015)

Ray McCarthy said:


> Well, that was a mockumentary, though they may have formed a real band and toured after the film.
> 
> However nothing to do with Shortwave Radio.



I was alluding to the moment the band played the US air force base and picked up air traffic control whilst playing their set...i.e. I've never experienced moments like that. I'm not sure if you've seen the movie or remember that bit - so apologies if you didn't have a clue what I'm talking about!

I was fully aware they are a made up (then sort of real) band and that that scene is probably impossible  - having watched it more or less when it was released


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## Ray McCarthy (Jul 4, 2015)

Venusian Broon said:


> the moment the band played the US air force base and picked up air traffic control whilst playing their set


No, that's slightly plausible as air traffic is VHF-AM. You'd need to be close to the transmitter aerial and the frequency is 110 MHz to 132MHz rather than the 65 MHz to 87MHz of VHF Low band (Earliest VHF two way radio).

In practice given the location other aerials and any location for a concert on an airbase it's unlikely, but unlike some other pranks in the film, it's realistically feasible. You'd only hear the tower, not the plane, unless the plane taxied pass the concert hall (in which case you'd hear the plane even if you didn't hear the tower).
  I'm sure though I can demonstrate the effect with a suitably poorly designed valve or transistor amp in the Car park of Shannon Airport. I think though Shanwick masts (which has FAR more VHF traffic) is Ballygireen, near Newmarket on Fergus. But that might be just Shortwave. The Shanwick VHF mast might be on Woodcock hill. I can try a directional aerial to find the location.


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## mellotronman (Jul 5, 2015)

Most of the 'set pieces' in This Is Spinal Tap are based (if only vaguely) on real bands, the 'PA picks up local transmitter' gag being a story about Black Sabbath. Allegedly, guitarist Tony Iommi was using an early, primitive wireless system, which began picking up a local cab firm during soundcheck. Said firm wanted paying to switch off for the evening (understandably), but kept upping their demands until the band gave up in disgust. Everything ran smoothly during the gig until Iommi's tiresome solo spot, at which point a radio message to one of the firm's taxis came through loud and clear. Allegedly... Um, we've moved a long way from SF, haven't we?


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## Venusian Broon (Jul 5, 2015)

mellotronman said:


> Um, we've moved a long way from SF, haven't we?



We're in the History bit of the site, no need to mention SF.


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## Ray McCarthy (Jul 5, 2015)

mellotronman said:


> Allegedly, guitarist Tony Iommi was using an early, primitive wireless system, which began picking up a local cab firm during soundcheck.


However many P.A. amps will pickup a nearby taxi base very easily, no need for EXTRA primitive wireless in the mix. Esp. the older VHF Low Band Taxies.  

That's the history bit.


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## J Riff (Jul 5, 2015)

Oh yes, a band I know here in Toronto changed their name to Vivaldi's Amp after the guit amp wouldn't stop bringing in Vivaldi between songs.
My base station is a CB... Realistic Navaho TRC-432 I thimk... the antenna is missing.
I want to play a couple Tap songs, like _Majesty of Rock_, but no-one is up for it.


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## Ray McCarthy (Jul 5, 2015)

J Riff said:


> My base station is a CB... Realistic Navaho TRC-432


So no Shortwave, no VHF, just CB band  (26.5MHz to 27.9MHz depending on country).   I suspected that.
Realistic is Tandy / Radio Shack badge, probably same model as some other make. Radio Shack are recently gone.


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## Phyrebrat (Jul 5, 2015)

I love these things, too. I've written a shortish story 3/4ths the way through inspired by Numbers Stations. They're used quite interestingly in _Fringe_ and in the superb movie _The Banshee Chapter_.


pH


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## BigBadBob141 (Jul 6, 2015)

Has any one heard of the Russian Woodpecker, my brother used to regularly pick it up on his short-wave set.
It was a continual repetitive tapping tone a bit like a manic woodpecker.
I later found out the it was an attempt by the Russians to develop over-the-horizon radar.
You can read about it on Wikipedia under "Duga-3".


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## Ray McCarthy (Jul 6, 2015)

It was over the horizon radar. It's gone. 

Strictly speaking WWII  UK Radar was far over the the optical horizon.

Stealth aircraft invisible on modern radar show up on lower frequency obsolete radar systems.


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## BigBadBob141 (Jul 6, 2015)

REF: Ray McCarthy
Come back Chain Home, all is forgiven!!!


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## BigBadBob141 (Jul 6, 2015)

P.S.
Talking about early radar, whenever I see a documentary about the Battle Of Britain they always obviously go on about it's importance.
It was very important, however this was only one part of the tracking system.
The radars were great for looking outwards to France and Holland, giving a good early warning of a raid building.
But once the planes were past the coast and inland they could no longer be seen by radar.
The rest of the job of tracking them fell to the Observer Corps.
Armed with binoculars, sighting gear and a telephone they did an outstanding job of keeping track of the raiders inland.
Mainly made up of civilian volunteers I don't think they have received the recognition they deserve.


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## Ray McCarthy (Jul 6, 2015)

BigBadBob141 said:


> But once the planes were past the coast and inland they could no longer be seen by radar.
> The rest of the job of tracking them fell to the Observer Corps.


They did add other Radar systems at other locations, airbases and on planes as the war progressed.

One of the worst losses, testing the airborne systems
https://en.wikipedia.org/wiki/Alan_Blumlien

But in WWI and WWII sound and vision was used. The Observer Corp was obviously important initially,.


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## PaulMmn (Jul 6, 2015)

Although an SSB tuner makes listening to an SSB Shortwave broadcast easier, you can listen (sort of) on a standard AM tuner (that covers the shortwave bands).  See http://www.hamuniverse.com/ssbinformation.html for info on amateur broadcast methods.
--Paul E Musselman


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## Ray McCarthy (Jul 6, 2015)

Esp. if you have a second shortwave radio to hetrodyne against it (tune the 2nd one 455kHz higher or lower). Adjust spacing for best effect. The local oscillator of the second set adds the missing carrier so that the AM detector works.

However image rejection, intermodulation is poor and bandwidth too high. A second hand Sony ICF2001D is a bit cheaper than an AM /FM LW/MW/VHF "Roberts revival" which is x10 more price than same quality Tesco World band set, which has LW/MW/VHF and NINE AM  shortwave bands too, for €10 (no SSB though). It's about the only radio Tesco sells that's any good. The speaker is tiny & tinny but it's fine on headphones or a decent 4" external speaker. 
http://www.tesco.com/direct/tesco-rad-108-world-band-radio/498-0233.prd
There are lots of similar style Chinese ones (and even a Roberts at silly expensive price). But all the other ones I tested didn't have LW and were rubbish on MW as they had only a ferrite slug instead of a proper MW ferrite rod aerial.  I buy radios, test them and take them apart!


The Sony ICF2001D has AM, narrow AM, Synchronous AM (upper or lower side band to avoid co-channel whistles), SSB (LSB-CW and USB) 150KHz to 30MHz, VHF-AM Air band and VHF-FM (covering Japan, USA and Western Europe VHF-FM bands, but not the nearly gone East European OIRT VHF band). It's dual conversion, so decent image rejection and bandwidth. I don't think any of the domestic  consumer radios sold today are as good, you need specialist Amateur or Professional sets now. There is a slightly different US version (ICF2010D possibly) and Middle East Version.
http://www.radiomuseum.org/r/sony_icf_2001d.html
Only really available on eBay as they are about 30 years old!

The common PLL digital display clock radios are useless  as it's up/down buttons and most are poor single chip implementations. Only any good as a local FM Radio alarm clock. Unusable LW (if even fitted) poor MW and worse SW.


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## Dave (Jul 6, 2015)

BigBadBob141 said:


> Has any one heard of the Russian Woodpecker, my brother used to regularly pick it up on his short-wave set.
> It was a continual repetitive tapping tone a bit like a manic woodpecker.
> I later found out the it was an attempt by the Russians to develop over-the-horizon radar.
> You can read about it on Wikipedia under "Duga-3".


Spoiler Alert... It sounds like the Venetian Blind blowing in the wind, while tied to the Morse Code straight key in the film *On The Beach.* I wonder if it was an inspiration for that scene?


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## Ray McCarthy (Jul 6, 2015)

I've only read the book


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## Dave (Jul 6, 2015)

I haven't read the book  but it is a major letdown in the film when the travel all that way thinking it is a human being. It's near the end, so I've completely spoiled that film for anyone who hasn't seen it.


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## Ray McCarthy (Jul 7, 2015)

Morse (CW) is just a carrier on/off, so is a pure tone, the exact pitch depending on the receiver's tuning.
The woodpecker didn't sound like cw at all. Quite harsh, though I've not heard it for many years.

A blind blowing in the wind hitting a key wouldn't sound like Morse as it has a distinctive rhythm no matter what speed it is.

-- --- .-. ... . / -.--.- -.-. .-- -.--.- / .. ... / .--- ..- ... - / .- / -.-. .- .-. .-. .. . .-. / --- -. -..-. --- ..-. ..-. --..-- / ... --- / .. ... / .- / .--. ..- .-. . / - --- -. . --..-- / - .... . / . -..- .- -.-. - / .--. .. - -.-. .... / -.. . .--. . -. -.. .. -. --. / --- -. / - .... . / .-. . -.-. . .. ...- . .-. .----. ... / - ..- -. .. -. --. .-.-.- / - .... . / .-- --- --- -.. .--. . -.-. -.- . .-. / -.. .. -.. -. .----. - / ... --- ..- -. -.. / .-.. .. -.- . / -.-. .-- / .- - / .- .-.. .-.. .-.-.- / --.- ..- .. - . / .... .- .-. ... .... --..-- / - .... --- ..- --. .... / .. .----. ...- . / -. --- - / .... . .- .-. -.. / .. - / ..-. --- .-. / -- .- -. -.-- / -.-- . .- .-. ... .-.-.- / .- / -... .-.. .. -. -.. / -... .-.. --- .-- .. -. --. / .. -. / - .... . / .-- .. -. -.. / .... .. - - .. -. --. / .- / -.- . -.-- / .-- --- ..- .-.. -.. -. .----. - / ... --- ..- -. -.. / .-.. .. -.- . / -- --- .-. ... . / .- ... / .. - / .... .- ... / .- / -.. .. ... - .. -. -.-. - .. ...- . / .-. .... -.-- - .... -- / -. --- / -- .- - - . .-. / .-- .... .- - / ... .--. . . -.. / .. - / .. ... .-.-.-

See
http://morsecode.scphillips.com/translator.html
note the default there is 30wpm, which is rather fast. Re-try at about 22
Minimum to pass an exam might be 12. Best to learn at about 15, too slow and you don't catch the rhythm and can't get faster.

Writing a program to generate morse is trivial (I've done it in several programming languages). Even in 1930s there was ability to generate paper tape from QWERTY teletype keyboard. The tape could be fed at any speed on the transmitter.

Decoding received morse by computer is very much harder and can have these stages:

Decoding the tone to on/off
deciding if on is a dot or dash
deciding if off is an inter symbol pause, inter letter or inter word pause.
Adaptive loop to re-determine timings

dictionary look up of morse strings to text.

I did a program in VB6 with the first stage using off the shelf tone decoder DSP. It only worked with very good Morse. The morse decoder in some commercial programs was far better (MiixW). A retired Marine Radio operator I know has good enough morse for the MixW software. People in contests use all pre-prepared computer generated replies.


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