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Cracking Codes: Interactive Adventures at the Spy Museum | September 01 2025, 18:15

In the spy museum yesterday, one of the devastatingly informative terminals, where you had to crack the code, allowed you to hack into it too

The Ingenious Spy Device Gifted in Friendship: Unveiling The Thing | September 01 2025, 01:03

Today in the museum I saw The Thing in person – simply a brilliant espionage device. In 1945, a group of Soviet schoolchildren presented a large wooden Great Seal of the United States to the U.S. Ambassador in Moscow, Averell Harriman, as a “gesture of friendship”. The seal was beautifully hand-carved and hung in the ambassador’s office for a whole 7 years. And it leaked secrets!

No batteries involved! It was all very clever, especially for 1945.

Essentially, it was a passive radio relay or “parasitic resonator”. Inside the wooden seal was a small metal cylinder with a membrane and an antenna-rod.

Soviet operators directed a specific frequency radio wave (about 330 MHz) into the ambassador’s office.

Inside the device was a cavity resonator, tuned to the same frequency. It “responded” to the radio signal and began to retransmit it back.

On one side of the cylinder was a thin flexible membrane. It vibrated from the sound in the room (voices, footsteps).

The vibrations of the membrane altered the capacity and resonance parameters of the device, slightly shifting the reflected radio signal by frequency and phase. This was the modulation of speech onto the external signal.

Outside the building (like in a KGB car nearby), the retransmitted signal was received and the sound modulation was extracted – effectively capturing the overheard conversation.

Why was this almost impossible to detect? The device had no battery and emitted nothing by itself. It “came to life” only when irradiated with an external radio signal. In standard radio monitoring checks, it remained “dead”. Essentially, it was akin to an ancestor of the RFID tag – a passive device that operates only on external request.

But most interestingly, the inventor was Leon Theremin, the same person behind the musical instrument “thereminvox” (played with hands in the air).

His biography reads like a novel. In the early 1920s, Theremin went to the U.S., patented his thereminvox instrument, and collaborated with RCA; his New York studio was visited by Charlie Chaplin, Albert Einstein, Gershwin, and other notable personalities. It is written that he visited the USSR – Already in 1926, he demonstrated television at the Kremlin.

At that time, televisions with screens the size of a matchbox were being created, but his television had a huge screen (1.5 x 1.5 m) and a resolution of 100 lines. In 1927, the scientist demonstrated his installation to Soviet military leaders K.E. Voroshilov, I.V. Tukhachevsky, and S.M. Budyonny:

state minds watched in horror as Stalin walked through the Kremlin courtyard on the screen.

This sight so frightened them that the invention was immediately classified and quietly buried in the archives, and television was soon invented by the Americans.

Eventually, in 1938, he secretly returned to the USSR, but was soon arrested as a “non-returnee” and sent to the camps, but his talent was still used in the so-called “sharashka” – on projects together with Sergei Korolev, including the development of radio-controlled apparatuses and listening systems, including the aforementioned “Great Seal bug”.

Beijing Parade Marks 80 Years Since China’s WWII Victory | August 31 2025, 14:02

On September 3rd in Beijing, a military parade dedicated to the 80th anniversary of China’s victory in World War II will take place. Apparently, I did not pay enough attention during history lessons at school: it turns out that China’s losses during WWII were almost comparable to those of the USSR, considering the official figures (in both cases, they are significantly lower than the actual ones). However, there is a catch – the war between China and Japan began in 1937, and later merged with World War II when Japan attacked the USA and its allies in 1941, officially making China part of the anti-Hitler coalition. Germany in 1937 was just preparing: a year later, in 1938, the Anschluss of Austria began, and another year later (1939) – the invasion of Poland, and at the same time the USSR attacked Finland.

Meanwhile, in Germany, it is considered that the precision of German accounting was incomparably higher, and the cumulative losses of the aggressors, together with Japan, turned out to be four times less than the cumulative losses of the defenders.

The figure of China’s losses mainly consists of civilian population. Their military losses were 3-4 million, while 12-17 million suffered from bombings, punitive actions, diseases (remembering Japanese Unit 731 and biological warfare) and other war consequences.

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Below I quote my post from January 25th of this year – just relevant and timely:

Who won the Second World War? Interestingly, note that no one paid attention to Trump’s words about the Second World War in his recent tweet-ultimatum.

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He writes “Russia helped us win the Second World War” — everyone noted the incorrect figure of 60 million losses, but somehow not this.

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I found an interesting study from 2017. It was a survey (1,338 people) from 11 countries including 8 allied countries and 3 Axis countries.

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It showed significant differences in how the former Soviet Union and 10 other countries remember the war.

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Events marked by representatives of the Soviet Union were almost completely different from those mentioned in other countries. Besides, Russians stated a greater responsibility for the victory in the war (75% of military efforts), than representatives of any other nation (although the USA and Great Britain also estimated their contribution as more than 50%).

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However, when people from each country assessed the contribution of other countries to the war, they attributed a greater role to the USA than to the former Soviet Union.

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An interesting finding is that, when asked why the USA dropped atomic bombs on Japan, most people from ten countries responded that it was to win the war, except for Russians.

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Moreover, the older the respondents were in 7 of these countries, the more often they agreed with the statement that the USA dropped the bombs to end the war.

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Russia (USSR) in the survey results demonstrates a unique narrative centered on the Eastern Front, unlike Western countries.

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Most countries (including former Axis countries) focus on events related to the USA and Great Britain, such as Pearl Harbor, the Normandy landing, the atomic bombings of Japan, and the Holocaust.

USSR holds a central place in the Russian narrative (75% contribution to victory). The USA and Great Britain also overestimate their evaluations, stating their contribution exceeds 50%, focusing on the Western Front and the Pacific Campaign. The total estimates of the contribution of the eight allied countries amount to 309%, showing the effect of “national narcissism”. Most countries prioritize the USA (27%), while the USSR — 20%.

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Four events gained the status of “key” (mentioned by more than 50% of respondents): the attack on Pearl Harbor, the atomic bombings of Japan, the Normandy landing, and the Holocaust. The Russian narrative concentrates on events termed in Soviet and contemporary Russian historiography as the Great Patriotic War (1941–1945). Russians highlighted unique events: battles near Stalingrad, Kursk, Moscow, Berlin, and the blockade of Leningrad. Thus, although the USA and Russia fought together as allies, research shows that there is almost no overlap in which events are remembered as most important. Members of each group mainly remembered those events related to their own country. However, this is not surprising.

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On the subject of atomic bombings, most respondents believe that the purpose of the bombings was to end the war. Russians see this event as an act of intimidating the USSR. Opinions within countries vary by age: older generations are more likely to support the official version of ending the war.

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In France in 1945, 57% of the population considered the USSR the main victor. By 2004, this figure had dropped to 20%, while the share of the USA increased to 58%.

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The reasons are clear: history textbooks and popular culture reinforce national emphasis. In the USA and Great Britain, films and books praising their role in the war predominate. The USSR and the USA fought on different fronts and represent different ideological systems, which determined the narratives. And of course, all countries overstate their role in historical events.

Aladdin’s Chinese Roots and the French Connection | August 30 2025, 11:39

In the original tale of “One Thousand and One Nights,” Aladdin is a boy who lives with his mother in China (!). It is often emphasized that the story takes place in China, but the names of the characters are still Arab. Some believe that Aladdin is Chinese, although of course nationalities did not exist back then.

Moreover, it’s generally complicated with where the tale originates. In “1000 and One Night” (or Arabian Nights) Aladdin was added by the French translator Antoine Galland, who was told the tale by “Maronite Hanna from Aleppo” Hanna Diyab, even the date from the diaries is known – May 5, 1709. Over the course of a month, Diyab told him fifteen more tales. Ten of these, including “Ali Baba,” were later published in the last four volumes of Galland’s “Nights” (1712–1717). Thus, “1000 and One Night” was written by a French translator based on motifs from various places.

Writes twenty-year-old Diyab, the one who told the translator.

“There was an old man who often visited us. He was in charge of a library of Arab books. He read well in Arabic and translated books from this language into French. At that time, he translated the book Tales of 1001 Nights. This man asked for my help with some issues he did not understand, and I explained them to him. The book was missing several nights, and I told him the stories I knew. Then he supplemented the book with these stories and was very pleased with me.” (MS Sbath 254, f. 128a)

Exploring the Boundless Spectrum: The World of Animal Hearing | August 29 2025, 17:56

From my notes as I read Ed Yong’s Immense World—

“..It is known that the range of audible frequencies for animals is different from that of humans, but I didn’t realize just how different. Imagine the highest pitch in the world—it would be just under 20 kHz, as it’s considered the upper limit of the audible range. Both the upper and lower limits tend to decrease with age. Most adults can’t hear sounds over 16 kHz. Anything above 20 kHz we call ultrasound.

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So, it turns out that our closest relatives, chimpanzees, can hear up to 30 kHz, dogs up to 45 kHz, cats up to 85 kHz, mice up to 100 kHz, and moths even up to 300 kHz. Imagine, there are so many high-frequency sounds around us, and how rich their sound world is compared to our limited one. It would be interesting to wear headphones that compress the range from 20-40000 Hz to 20-15000 Hz. Many animals, such as mice, actively use ultrasound for internal communication, beyond the hearing range of their predators.

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And when the topic of ultrasound comes up, it’s impossible not to mention bats with their echolocation. Turns out, it’s a wildly interesting topic.”

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Probably everyone knows that bats successfully hunt in caves, where no light penetrates at all, and they don’t crash into stalactites and stalagmites. There’s an English saying, blind as a bat, but actually, they can see. Some species see better, others worse. But let’s talk about echolocation.

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In general, it’s just radar. The bat screams, the sound bounces off a tree, comes back into its ears, and it gets information about how far away the tree is and whether to slow down or not. But the devil, as they say, is in the details. “Engineering” ones.

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Firstly, high-frequency sound attenuates quickly, so you need to shout very loudly for something to bounce back from a few meters away. Beyond that, bats simply don’t “see.” So, they do indeed shout very loudly, and it’s a directed scream. Specifically, they measured 138 decibels, the sound level of a jet engine if you stand next to it. But in the ultrasonic range.

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Secondly, when they scream so loudly, they need to plug their own ears so as not to kill their sensitive apparatus. It turned out that they have special muscles that block the inner ear during the scream.

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Thirdly, both they and their prey are on the move, very fast and erratic. Meanwhile, the speed of sound is about 343 meters per second. The bat’s brain must calculate the difference between the signal and the echo, taking into account both its own movement through space and the movement of the prey. It turned out that the bat’s vocal muscles can contract up to 200 times a second. Moreover, the frequency depends on the phase of the hunt. 200 times—that’s the final phase, when the moth is right in front of the nose, and tiny movements need to be tracked.

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Fourthly, the bat’s brain also has to cope with creating interference between what was shouted out two moments ago and what was shouted out a moment ago. Considering that the sound can echo off the far wall and the near branch. Plus there are waves from the cries of other bats, and they’re usually very numerous in caves. To manage this, they seem to throw a bit different modulation, plus this musculature allows them to “fire” very short pulses—a few milliseconds—and to renew pulses at their own frequency through very short intervals. Imagine what kind of computer in their brains performs the inverse Fourier transform.”

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So, all this works pretty well in small groups. But for example, the Brazilian free-tailed bats live in groups of millions. Really, together 20 million mouths shout something and wait for their echo from the walls and each other. You can’t just pick modulation and frequencies that easily, but somehow they manage. Not perfectly, and if they gather in a really big bunch in the cave, then they perform their commute to the hunt and back to the cave “by memory” – probably due to issues with echolocation. When a “door” was placed at the entrance to the cave, a bunch of bats crashed into it.

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Fifth, consider how they determine distance. It’s necessary to calculate the difference between the signal sent and the signal received (amid a bunch of noise from other bats), and for hunting, it needs to be calculated very precisely. And sound of course isn’t light, but 343 meters per second is also a lot. So studies have shown that bats can recognize differences as little as 1-2 millionths of a second, which allows them to determine distance to fractions of a millimeter. In other words, our eyes are significantly less accurate than their ears.

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Plus, a moth is actually a fairly complex 3D creation that reflects sound differently with its different parts. Otherwise, bats would eat everything that moves. They recognize. In complete darkness. A mouse’s scream contains a whole palette of frequencies, which reflect differently off parts of a moth, and the mouse’s brain somehow manages to translate this into a coherent picture. Moreover, for each of the constituent frequencies, the delay will be its own.

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Then, all this information is layered over time. Roughly speaking, a snapshot from one point is combined with a snapshot from a point a half meter to the right, then from a point half a meter forward, and so on many, many times, which enhances “sharpness” and detail. Overall, it’s the same with us – we only see the spot in front of us clearly while the rest is constructed by the brain. But the brain of a bat weighs 1-2 grams against our half kilogram.

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Think about it, you’re flying with such a built-in radar, and in front of you are two branches at the same distance, which produce essentially the same echo for their ears. And to distinguish them and understand that it’s not one object but two, you really need an advanced brain.

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So, they send pulses lasting 1-20 ms, plus longer pauses between pulses. The pulses are complex in terms of frequencies, so such bats are called frequency modulation (FM) bats. But there are about 160 species that have a much longer cry—many tens of milliseconds but with short pauses, and instead of a complex gamma of frequencies, these use a pure “note.” These bats are called CF—constant frequency. So here’s the thing with these bats—there’s a problem with the Doppler effect, which is an increase in frequency as the distance decreases. Since their brain is tuned to a strict frequency, like 87 kHz for example, they might lose their prey if the echo that reaches their ears is shifted in frequency. And what they do—they shout at a sound speed lower, so that after the Doppler effect it arrives at the correct frequency for the brain.”

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Incidentally, their radar has two modes—forward and downward, the echoes from which are processed separately. The downward radar provides information about position in space, and the forward radar—about the position in space of the prey.

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When I researched the subject, I found that yes, after 20 kHz humans hear nothing, with one exception—frequencies of 2.4 GHz and 10 GHz, which actually belong to the microwave range. Yes, humans can “hear” these frequencies, but not with the ear, but “hear.” This phenomenon is called the microwave auditory effect or the Frey effect. Initially, this effect was registered by people working near radars during World War II, and the sounds they perceived were not heard by others. It turned out that when pulsed or modulated microwave radiation was applied to areas around the cochlea, it was absorbed by the tissues of the inner ear, accompanied by their thermal expansion. In the course of this process, shockwaves are produced, perceived by humans as sound, which no one else hears. It was also discovered that with the appropriate choice of the modulating signal, it is possible to transmit information to a person in the form of individual words, phrases, and other sounds. Depending on the radiation parameters, the sound created in the head can be irritating, cause nausea, and even disable. The volume of the perceived sound can be changed, but acoustic trauma is not possible, as the eardrum does not participate in the process at all. Generally speaking, the method of specifically transmitting sonic messages that are absolutely inaudible to others opens up a whole bouquet of possibilities. I wonder if research is still being conducted on this topic. Google shows that they used to be pretty intense.”

I once published this along with a video, and Facebook reckons that if you publish a video, the text should be one, at most two lines. And in the end, almost no one saw this text. Everyone just watched the video of a bat flying around my apartment 🙂

Cycling for History: A Book and An Unexpected Glimpse into 1930s Migration Trends | August 24 2025, 18:27

I couldn’t resist and bought the book Great Depression in Perceville, VA, where I arrived by bike. I still don’t know how to carry it back for an hour in cycling clothing without a backpack. Interesting note on a random page

Translation:

AMTORG RECEIVES 100,000 APPLICATIONS FOR 6,000 QUALIFIED JOBS IN RUSSIA

(Business Week, October 7, 1931, pp. 32–33)

NEW YORKERS make up the bulk of Americans who have decided, at least for now, to tie their fates with the Russians. Pennsylvania, New Jersey, and Illinois contribute the highest number of applications for the new call for “6,000 qualified workers,” with Michigan, Ohio, California, and Massachusetts also being well represented.

The “Amtorg” office in New York received over 100,000 applications for these 6,000 job slots. Just one morning alone saw 280 applications. All states except ten were represented. Alaska and Panama also contributed one applicant each, and 18 Canadians wanted “to try their luck in Russia.”

Industrial states, naturally, provided the largest number of applications, but others were represented as well. Iowa, Texas, and Idaho also contributed some number of qualified workers.

Since it is widely known that Russia is “industrializing,” most applicants are skilled workers in machinery, railroads, metallurgy, automotive manufacturing, or the construction industry. A look at the qualifications of 280 applicants from one “typical” morning showed that specialists of all professions were looking for work, even if it meant moving to Russia and being paid in rubles. Among them were: 2 hairdressers, 1 funeral director, 2 plumbers, 5 painters, 2 cooks, 36 “clerical” workers, 1 lathe operator, 9 carpenters, 1 aviator, 58 engineers, 14 electricians, 5 salespeople, 2 printers, 2 chemists, 1 shoemaker, 1 librarian, 2 teachers, 1 cleaner and dyer, 11 auto mechanics, 1 dentist.

About 85% of the applicants are U.S. citizens, only 40% of whom were born in the country. 60% of the foreigners primarily come from Eastern Europe. A few African Americans applied, but their numbers are small, as most of them are unskilled workers.

Women constitute only a small portion of applicants, although many wives decided to accompany their husbands in this endeavor. Most workers applying are married and have children.

Three main reasons for wanting to get a placement are named: (1) unemployment; (2) dissatisfaction with conditions here; (3) interest in the Soviet experiment. Almost all foreign workers declare that they do not intend to stay in the USSR. Among engineers, only 10-20% plan to stay.

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This is 1931, one of the most challenging years of that period. Somewhere in the mid-thirties, it started to improve, and it must be said, WWII ultimately defeated it.

Inside Apple AirPods: Design, Battery, and Antenna Secrets Revealed | August 23 2025, 01:52

Very interesting video about how Apple Airpods headphones work (in the comments). You can read about it, or you can just like this post and go check out the original video in the comments. It has pictures!

Battery. 6 hours of operation, but the capacity is only 2% of the iPhone battery capacity. “Dead zones” in the battery, which lead to reduced operating time, can occur due to sudden temperature changes or even just dropping the headphones on the floor. There is a very dense “layered cake” made from a couple dozen layers of anode-cathode. Batteries of fake AirPods or cheap analogs are much worse. Physics: Poor packaging means less active material and fewer lithium ions moving with each cycle => reduced energy density and increased internal resistance => more energy is lost as heat => battery wears out faster.

Antenna. It is located in the stem because the human head significantly dampens the signal. But there is little space in the stem. Metal strip antenna, size 2 mm by 10 microns(!). That’s thinner than human hair. At such size, it cannot maintain shape on its own. In other consumer electronics, antennas can be etched on the printed circuit board, but this limits them to two dimensions. For the AirPod stem, there isn’t enough space. Therefore, Apple uses a clever solution. They embedded the antenna in the surface of a molded plastic cylindrical part. There, clever conductive plastic is used, with added metal. A laser engraves the exact shape of the antenna in the form of small channels with a rough surface. Then, this groove is subjected to electroplating, first with copper, then covered with gold to protect against corrosion. As a result, a durable conductive track is formed, which matches the 3D geometry of the molded part, which would be impossible to create using traditional machining methods. The plastic not only structurally supports the antenna. Other components are attached to it, such as the cable wrapping around the stem to connect the antenna to the Bluetooth chip, the pressure sensor in the stem.

Microphone. In AirPods, not electret microphones, but MEMS: a microelectronic” version of the condenser type. Well, actually, this is not only Apple – any modern TWS headphones, unless they are the cheapest ones. That is to say, modern microphones are made using the same technology as types – photolithography, layer by layer, only in this case it’s a mechanical device, with calculated cavities and flexible layers. Separately interesting is how they make the cavities – they make holes through which etching solution penetrates inside and dissolves the sacrificial layers of silicon dioxide.

Because of such microscopic size, there are several microphones. But why more than one microphone is needed? At the bottom of the AirPods, you will see a small mesh that allows air to enter the second microphone. When you talk, your voice reaches both microphones, but not at the same time. With a difference of only a few millimeters, the chip can detect a delay of six microseconds between when your voice reaches each microphone. This is enough to determine where the sound is coming from and focus on it. Since it precisely knows the distance the microphones are from one another, the chip can compare each signal and amplify your voice during calls.

The third microphone is for noise cancellation. It is located right in front of the speaker, inside your ear.

The microphones consume about 130 mA, which would quickly drain the battery if they were always active. That’s why they are only turned on when you make a call or use noise cancellation. But AirPods are always waiting for a Siri request. How is this possible without constantly active microphones? Here’s a clever solution. Inside the part that is in your ear, there is a small sensor—an accelerometer. It’s the same type of sensor used in phones to determine orientation. But here it serves a different purpose. Instead of measuring orientation, it senses vibration. When you talk, your voice moves through your jawbone. And this vibration is detected by the accelerometer. This low-power consumption signal is enough to wake up the system and activate the microphones when it senses you want to activate Siri. Imagine that, eh?

The sound in AirPods is tuned not “by ear,” but based on a scientific model of the “ideal sound” (Harman curve), which describes the combination of frequencies most people find most pleasing. For this, there is a complicated system of calculated vents and meshes — to control the air flow, which prevents the occurrence of unpleasant “humming” or sharp sounds inside the ear canal. The larger the cells — more air passes through, smaller — less. Such is the mesh, visible as black things on the white earphone—I thought it was for beauty. No, this is exactly that mesh. But at the same time, some kind of moisture protection must be made, and here the mesh is porous. It is claimed that there is some sort of nano-coating that repels water.

Bluetooth. Why it is so immune to interference. Turns out, it uses frequency-hopping spread spectrum technology (Frequency Hopping). Bluetooth devices quickly switch between different channels many times a second and adapt accordingly.

Exploring a Conditional Investment-Based U.S. Visa Program | August 21 2025, 21:23

I wonder if a U.S. visa program would work where specially authorized American investing organizations collectively invest, say, $500,000 in each candidate who files a petition and is ready to pay a hypothetical $20-50K. The money goes to the government, but it returns it monthly with interest. Then, he moves to the U.S., gets a job, and pays back the “investors” from legally earned money, like a student loan. “Investors” help him find a job. If he loses his job, and can’t find another, he can pay from savings for some time, but afterward — he must return home. No savings — go back home. Violated the law (criminal) — go back home. But each such negative case affects whether the “investor” will have the opportunity to invest in new ones.

Investors help with job finding if needed, but there’s no coercion or serfdom, because it doesn’t matter what kind of job the person has, as long as it’s legitimate, and the debt is deducted from the salary. Until the debt is paid, a person’s profile affects the “investor’s” performance indicators, and in case of poor indicators, the investor loses their license or priority.

It’s assumed that, given existing quotas, the “investor” has an interest in finding the smartest and most hardworking people worldwide and subsequently placing them in the local market. If they perform poorly, they simply can’t operate.

After full repayment, he gets the right to citizenship. This could attract talented individuals, support the economy, and ensure responsibility. What do you think?