Talk:The Thing (listening device)

Article title
I think "The Great Seal bug" or "Great Seal bug" would be a better article title. Comments? Mikebar (talk) 07:22, 13 May 2008 (UTC)
 * I believe it's usually called the Thing and the name Great Seal Bug is just used for clarity; --  DasRakel  ✍  07:43, 14 June 2009 (UTC)
 * At this time I tend to disagree, look at the titles of published works, especially outside of the UK. Mikebar (talk) 15:28, 1 January 2012 (UTC)

Electromagnetic 'Induction"
'''WARNING! RANT ALERT!''' What? Some editors seem to have "induction" on the brain. It turns up in the most peculiar places whenever radio ie. electromagnetic waves are involved. The effects are NOT the same thing! Induction as I was taught, and as I understand it is a purely MAGNETIC phenomena(until it 'cuts' a conductor of course). RF involves Magnetic and Electric fields together (hence electro-magnetic)

A cavity resonator doesn't need 'induction' to operate. I Imagine a sealed micro-wave cavity resonator with a flexible (conductive) membrane at one end could, possibly, work. When the appropriate micro-wave frequency that the cavity resonates at is aimed at it, any audio striking the flexible membrane will cause it to flex and change the cavities operating frequency at a rate equivalent to the audio.ie Frequency modulation. This 'modulated' micro-wave energy could easily be received and de-modulated to recover the speech. FM is naturally resistant to electrical interference, more so than AM, so this system could, theoretically, give very good speech quality.

The operating principle described seem quite vague. A "capacitive membrane" and a "condenser microphone" are NOT, necessarily the same thing. A condenser microphone, requires a small DC 'bias' current to operate. I don't see how this could be achieved as stated as, "it...had no power supply or active components". A 'practical' Electret microphone, which does not require a DC 'bias' was not invented at Bell Labs until 1962. Therefor I have some problem with believing a 'condenser' microphone, 'capacitive membrane' perhaps.

¼ wave antenna, comes out to 8.95 inches/22.77cm which seems about right, if the bit pointing down in the photo is the antenna. If they could have got higher microwave freqs, say 3 Ghz, then the wavelength would have been only 10 cm! ¼ wave of 2.5 cm/ 1 inch! TINY. Probably NOT possible back then.

This quote is from Covert listening device
 * "The Great Seal bug.....The bug was unusual in that it had no power source or transmitter, making it much harder to detect — it was a new type of device, called a Passive Resonant Cavity Bug. The cavity had a metallic diaphragm that moved in unison with sound waves from a conversation in the room. When illuminated by a microwave beam from a remote location, the cavity would return a frequency modulated signal." Which is different (but more technically correct) than what this, the main article says!

Should always go back to the source here, GreatSealBug they have diagrams and pics of the actual device. Antenna 9" long!
 * "It was simply a resonate(sic) chamber, with a flexible front wall that acted as a diaphragm, changing the dimensions of the chamber when sound waves struck it. It had no power pack of its own, no wires that could be discovered, no batteries to wear out." Which is pretty much what I was saying, at least this is a bit inconsistent between related articles in the one encyclopaedia!

So NO condenser microphone, as it is normally understood, except in the broadest possible meaning of the term. AND NO "electromagnetic induction", except MAYBE in the broadest possible meaning of the term. RADIO IS NOT the same as electromagnetic induction!

I have no doubt that the device worked, just that the description in the article is not correct. AS I believe I have shown by referring back to a source/reference document.

These sections need to be rewritten to be consistent with the source and each other. Now, I can have a nice cup of tea and a bikkie. I need it! --220.101.28.25 (talk) 19:58, 4 December 2009 (UTC)

More Relevant Data/ Web-site references
More info, not in the article(yet) on how the 'Thing' works. "Eavesdropping using microwaves - addendum" audiodesignline.com

Very nice diagrams, also seen on other sites. Need to look if they are availabe for Wikipaedia use. 'Cut-away'side view Showing how it really operates
 * Quote(my bolding):
 * "The resonant cavity transmitter is (a) simple technical device called a passive radiator. A layer of thin metalized material is stretched across a closed metal tube. The size of the tube determined its resonant frequency. An antenna, is attached to the base of the cavity. The cavity is irradiated with a beam of radio frequency energy from an external source. The size of the cavity and the length of its antenna are designed so that a harmonic of the inbound radio frequency energy is rebroadcast. The metalized diaphragm acts as a transducer, and the audio range energy modulates the returned radio frequency signal that, in turn, is picked up by a receiver in a nearby listening post. It is important to note that the microwave signal that “powers up” the device is not the same frequency as the outbound signal."

The Article currently says "in turn modulated the radio waves that struck and were reflected by "The Thing." As per the description above, INCORRECT, not reflected, received and re-transmitted on a harmonic(multiple) of the 'activating' transmission, "a harmonic of...radio frequency energy is rebroadcast" NOTE: I am not just arguing this from the information of the references, as they can be wrong too, BUT they are consistent with my own formal technical training and experience in Electronics, Radio Communications and Microwave Techniques. The article is NOT so compatible with the science. --220.101.28.25 (talk) 02:31, 5 December 2009 (UTC)


 * I disagree. There's nothing in the described construction that could generate harmonics.  You'd need a diode or such for that. Dicklyon (talk) 02:41, 29 April 2021 (UTC)

Operating principles

 * The ‘Thing’, designed by Léon Theremin, was very simple by today's standards, but ingenious. It consisted of a conductive/metalised membrane, stretched across a closed metal tube (a passive cavity resonator), and a small quarter-wavelength antenna; it had no power supply or active electronic components.


 * The device becomes active only when 'irradiated' with a beam of the correct frequency radio waves from an external transmitter. Sound waves caused the membrane to vibrate, which varied the resonant frequency of the cavity resonator. The size of the cavity and the length of its antenna are designed so that a harmonic of the inbound radio frequency energy is re-broadcast. The cavities operating frequency was altered at a rate equivalent to the audio, ie. Frequency modulation (FM). This 'modulated' micro-wave energy could easily be received and de-modulated to recover the speech. FM is naturally resistant to electrical interference, more so than AM, so this system could, theoretically, give very good speech quality.


 * Theremin's design made the listening device very difficult to detect, as it was very small, had no power supply or active components, and did not radiate any signal unless it was actively being ‘powered’. These same design features plus the overall simplicity of the device made it very reliable and gave a potentially unlimited operational life.


 * It’s discovery suggested the reason for microwave radiation already detected being aimed at US Embassies in various overseas locations.


 * The characteristics (short wavelengths) of the frequencies used make it possible to use a very directional ‘horn’ or dish type antenna to literally aim the activating signal at the spot where the ‘Thing’ is mounted.


 * Further developments in solid state microwave (and other) electronics, based on the same principles used by Theremin, make it feasible that the same affect can be obtained from suitable metallic objects without any concealed ‘special’ device at all! No membrane, cavity resonator or antenna!

--220.101.28.25 (talk) 21:16, 5 December 2009 (UTC)

Frequency modulation?
New section moved to bottom of page. Cuddlyable3 (talk) 12:48, 2 May 2010 (UTC)

I think it is impossible for passive resonator to oscillate at frequency different from the frequency of external source (or multiples of this frequency in case of non-linear resonator). So, frequency modulation is impossible in this case. May be it is phase-shift modulation, but most probably it is just amplitude modulation. 188.123.243.103 (talk) 12:48, 16 March 2010 (UTC)


 * But FM is possible. The article Q factor says: "Sinusoidally driven resonators having higher Q factors resonate with greater amplitudes (at the resonant frequency) but have a smaller range of frequencies around that frequency for which they resonate; the range of frequencies for which the oscillator resonates is called the bandwidth.". Provided the resonator Q is not too high it can re-radiate over a small range of frequency i.e. sound vibrations convert to frequency modulation. I don't know of any non-linearity in the resonator that would give harmonic radiation but if that is the case the FM deviation on a harmonic is multiplied by the harmonic number. Amplitude modulation is not helpful because an unintelligible full-wave rectified (frequency-doubled) version of the speech would be detected. Cuddlyable3 (talk) 13:09, 2 May 2010 (UTC)


 * There is still no comprehensive explanation on the net about the reception technology used. Most articles quote a harmonic being received, without further explanation of the mechanism for this harmonic to be generated, other hint to a reflectometer used with the emitter. Mihaiam (talk) —Preceding undated comment added 11:27, 2 October 2011 (UTC).
 * IIRC any signal except a perfectly pure sine wave, has harmonics. As no signal is 'perfect' all will have harmonic content. 220  of  Borg 09:26, 14 June 2015 (UTC)
 * Yes, the illuminating signal can have harmonics, of course, but this is beside the point. Did the Thing generate harmonics, or did it not? The referenced article that suggests the Thing generated harmonics (presumably as a design feature) offers no evidence to support this. There is no report of a non-linear device (eg diode) built into the Thing that would be required for harmonic generation. Indeed PM (equivalent to FM of a differentiated message), and AM modulation are both generated by a perturbed resonator, and yes, the modulation sidebands in either case are not the same frequency as the carrier. But modulation sideband generation is totally a different process than harmonic generation. It thus remains unclear, at best, the article's assertion that there was a response "at a different frequency" means, specifically. Without any evidence of non-linear processes in the Thing, the evidence suggests that this refers to sidebands, but I know of no article to cite that presents this straightforward analysis. Nadovich (talk) 14:35, 31 May 2019 (UTC)
 * I agree. Harmonics don't seem plausible from the described construction.  Modulation sidebands are the frequencies to be detected, whether AM or PM or both. Dicklyon (talk) 02:43, 29 April 2021 (UTC)
 * The threads for adjusting the front cover and the dissimilar metals from the plating would be enough to generate a weak harmonic for receiving a harmonic. The cavity dimensions allow for a resonant frequency of 1.8 GHz. This would be ideal as it would allow for high isolation from the illumination transmitter (300 or 600 MHz) and the use of a high-gain directional antenna on receive. 74.135.169.70 (talk) 07:20, 11 November 2022 (UTC)

Assuming that the device had never been discovered, it could easily have worked for 50 years or more.

 * Citation needed. Why fifty years? Was there a component which would have failed after fifty years? Fotoguzzi (talk) 02:57, 1 July 2010 (UTC)
 * Furthermore, the section Operating principles contains a seemingly-contradictory statement: These same design features plus the overall simplicity of the device made it very reliable and gave a potentially unlimited operational life. IMO the article should settle on one and offer either a citation or justification for the one picked. mattp (talk) 15:26, 26 July 2010 (UTC)


 * Agreed: the 50 year claim is unsourced and (to be fair) may have just been a figure of speech. Reworded.  86.182.103.115 (talk) 16:16, 7 June 2011 (UTC)
 * "Easily work indefinitely?" It's possible it could have worked indefinitely, but anything based on mechanical effects couldn't do it easily.  Easily is unsubstantiated.  Moreover, the entire idea that it could work indefinitely is unsourced.  Dataxpress (talk) 02:10, 20 November 2011 (UTC)


 * It could have worked until it broke mechanically. It was totally passive, it had no batteries. About the only moving part was the diaphragm. I believe it also had a tuning screw, so that slipping may have been possible. If the diaphragm got loose over time it would have worked less effectively, or the operating frequency may have shifted. 220  of  Borg 09:32, 14 June 2015 (UTC)


 * That's all speculation. We need a reliable source if we're going to say anything about longevity. Kendall-K1 (talk) 13:33, 14 June 2015 (UTC)


 * Not pure speculation. Naturally I'm not going to put my 'educated' opinion in the article! (I've been trained in RF electronics, but you only have my word for that, of course,) We know it had no batteries, and it was a totally passive device, until it had an RF signal of the right frequency aimed at it. The main failure mode would be mechanical, like the diaphragm tearing; or if an insect was able to crawl inside it, perhaps. 220  of  Borg 05:03, 15 June 2015 (UTC)

Competing discovery stories
We have two different discovery stories. Probably should consolidate them. Here are the two stories:


 * "discovered in a stroke of luck by a technician with an untuned video receiver"
 * "discovered by a British radio operator who overheard American conversations on an open radio channel"

Are the technician and the radio operator the same person? Was it a video receiver or audio? Kendall-K1 (talk) 18:22, 13 June 2015 (UTC)


 * No, apparently they were different people, in a different building at different times even! But at least once was with a radio receiver. But the truth of its detection appears to be a bit of each, or so says the source I found, at least. I was going to say that it was likely we would never know, as it was possible that a lot of deliberate disinformation about the issue was propagated as a version of 'The Thing'  was later used by the UK & US.


 * However I found, this in "History of the Bureau of Diplomatic Security of the United States Department", Global Publishing Solutions (October 2011) p.136. (No ISBN!) This gives the name/s of the technical staff who actually found the device (though it was 'detected' earlier by "a US Military officer") but that was after suspicions were raised when in the British embassy "a British officer overheard a  conversation ... on his radio receiver". The person who located it is named as "Joseph Bezjian", apparently deceased in 1986. 220  of  Borg 23:04, 15 June 2015 (UTC)

I took out the part about the detection being done with a video receiver. Yes, the source says that at one point, but then goes on to say it was a simple RF detector connected to the audio amplifier of a Schmidt device. I suspect "video" is being used here as a metaphor for "wideband", and I don't think including it adds anything to the article. Kendall-K1 (talk) 15:41, 10 January 2016 (UTC)

The Murray source says that the Brits discovered the device or a similar one, possibly at their own embassy, then alerted the US, who then found the device. So I don't think "independent" is quite correct. Kendall-K1 (talk) 14:21, 17 January 2016 (UTC)


 * What was the contribution of Joseph Bezjian, if any? Korny O&#39;Near (talk) 03:27, 18 January 2016 (UTC)


 * All I know is what I read in the sources. There is lots of info in Murray, but it's pretty disjoint and a bit contradictory since it's a bunch of individual stories. Kendall-K1 (talk) 06:21, 18 January 2016 (UTC)


 * Yes, that source is indeed chaotic and contradictory (the mysterious "little old man" seems to claim that he was the one who discovered the whole thing). Plus, I don't know if the Murray Associates homepage, AKA counterespionage.com, counts as a reliable source, as credible as it appears. In any case, a paragraph here, from John W. Ford's "unfinished memoirs", seems to shed light on Bezjian's involvement:

In March of 1951, I was on special assignment to the USSR in the combined interest of the British, Canadian and United States governments and their embassies in Moscow -- to search for and hopefully uncover the latest clandestine listening device being used by he Soviets -- a miniature electronic microphone, activated by a radio from some distance away. My travelling companion, Joseph Bezjian, worked for me as electronics technician. Months later he was honored by the Department of State for his fine work which lead to the discovery of an advanced miniature listening device hidden in the Great Seal of the United States -- a wooden replica hanging in Spasso House, the Ambassador’s official residence.


 * I modified the "Discovery" section a little based on that. Korny O&#39;Near (talk) 16:14, 18 January 2016 (UTC)


 * Looks much better, thanks. Yeah, I'm reluctant to rely on Murray, since it's a bunch of hearsay. Kendall-K1 (talk) 17:23, 18 January 2016 (UTC)


 * That's great. Now I'm wondering about the date of discovery - apparently, George F. Kennan wrote in his memoirs that it was discovered in 1952, while John W. Ford wrote that he and Bezjian discovered it in 1951 (see quote above). Conflicting memories? Korny O&#39;Near (talk) 20:27, 18 January 2016 (UTC)


 * Ford just says he was "on special assignment" in 1951, not that the bug was discovered then, although he does imply it was discovered soon after. "Months later" could easily be more than a year. Of course I would hope it didn't take that long. Kendall-K1 (talk) 21:34, 18 January 2016 (UTC)

Units
Shouldn't SI units be listed first per WP:UNITS? Or would this be considered a "non-scientific articles relating to the United States"? The device itself was Soviet, although the context of the article is mostly US. Kendall-K1 (talk) 21:55, 18 January 2016 (UTC)

Peter Wright
Discovery Section. It's been several tears since I have read Spy Catcher, but didn't Wright say that even though the US had had the device for some years, they had not only failed at discovering the scientific principles behind it, their attempts to reverse engineer the device was less than successful? Even though it was the Brits who gave them the heads up, handing the seal over would not have been a step they would have taken lightly. The article insinuates that hiring a foreign government, even an ally, was 'modus operandi'. (Took me a while to find the right Latin term, but I think Bob's my uncle). 50.64.119.38 (talk) 10:23, 21 June 2017 (UTC)

Original research
WP:OR. "This page in a nutshell: Wikipedia does not publish original thought. All material in Wikipedia must be attributable to a reliable, published source. Articles may not contain any new analysis or synthesis of published material that serves to reach or imply a conclusion not clearly stated by the sources themselves."

It is that simple. '''There is no primary or secondary source about The Thing that mentions the patent. And the patent does not mention The Thing.''' The editor is doing own research on Google Patent Search and making own analysis that there had been a prior patent. Whether the analysis is correct or not doesn't matter; the very fact is that the editor is doing original research, and that's what WP:OR prohibits.

"This includes any analysis or synthesis of published material that serves to reach or imply a conclusion not stated by the sources. To demonstrate that you are not adding OR, you must be able to cite reliable, published sources that are directly related to the topic of the article, and directly support the material being presented."

Best.

98.19.45.87 (talk) 05:13, 26 June 2018 (UTC)

Quarter Wave vs. Half Wave
I noticed in the article that it is speculated that the antenna functioned as a quarter wave antenna. This would work only if the antenna were attached to another conductive object that could be used as a counterpoise or ground plane. A quarter wave element in free space is not resonant. However, a half wave element is. Therefore, unless there was something conductive not visible in the photo, the lowest practical frequency for using this device was probably 660 MHz.

Ultimatefribble (talk) 22:58, 30 October 2019 (UTC)

Article source vary dubious
Most of the information in this article seems to be derived from Peter Wright's Spycatcher book, or from sources that based their writings on Wright's book. Wright's book is largely the regurgitation of previously published material considerably embellished with Wright's vivid imagination - a fact clear to technically qualified people who have read it. For example he claimed to have designed the guidance control system for the Blue Streak missile - before the rocket requirement was even initiated. In fact it was designed by Sperry. There are many other examples of Wright having us on. The book contains many quirks such as "The local oscillator [of a radio] always radiates sound waves as it operates...", which nobody with any electronics knowledge would say. Yet Wright claimed to be variously an electronic expert and scientific officer. things like "a shortwave high frequency megacycle." Even a schoolboy radio hobbyist wouldn't come up with that one. As such, this article should be seriously edited down, or bolstered by other references, or a prominent warning be given that the primary source is not trustworthy. Dionne Court (talk) 03:15, 12 January 2024 (UTC)

"The Thing (listening device" listed at Redirects for discussion
The redirect [//en.wikipedia.org/w/index.php?title=The_Thing_(listening_device&redirect=no The Thing (listening device] has been listed at redirects for discussion to determine whether its use and function meets the redirect guidelines. Readers of this page are welcome to comment on this redirect at  until a consensus is reached. Utopes (talk / cont) 01:32, 8 April 2024 (UTC)