Hey everyone, welcome back to My Weird Prompts. I am Corn, and I am feeling especially curious today. We are coming to you from our home in Jerusalem, and the weather is finally starting to feel like actual winter. It is that specific kind of Jerusalem cold where the stone walls of the house start to feel like blocks of ice, and you just want to wrap yourself in a heated blanket and never leave.
And I am Herman Poppleberry, ready to dive into the technical weeds as always. It is January eleventh, twenty twenty-six, and we have a fantastic prompt today from our housemate Daniel. He was at the airport recently—Ben Gurion, actually—and he was sitting at the gate, watching the chaos of a delayed flight to London. He started wondering how his noise-canceling headphones actually stay connected to his phone when there are literally thousands of other signals flying through the air in that tiny, glass-walled space.
It is a great question. If you have ever been in a crowded terminal, you see hundreds of people with those little white buds in their ears or big over-ear cans. Daniel mentioned that Bluetooth has a range of thirty to fifty meters. If you draw a circle with a fifty-meter radius in a crowded boarding area, you might have five hundred people in that circle. That is a lot of data packets fighting for the same airwaves. And that is not even counting the smartwatches, the tablets, the laptops, and the airport’s own infrastructure.
It really is a nightmare scenario for any radio engineer. And the amazing thing is that, for the most part, it just works. You do not suddenly start hearing the podcast the guy in seat twelve-B is listening to, and your music does not usually stutter unless you walk halfway across the terminal to get a coffee. But to understand why, we have to look at the invisible architecture of the two point four gigahertz band.
Right. And we have touched on this a bit in past episodes. I remember in episode one hundred sixty-four, we talked about radio frequency hygiene and how crowded the two point four gigahertz band is. We called it the "junk band" because it is where everything from baby monitors to microwave ovens lives. But Bluetooth seems to have some special tricks up its sleeve that make it more resilient than your average Wi-Fi connection in those high-density spots.
Exactly. To understand why Bluetooth is so robust, we have to talk about its philosophy. Most wireless protocols are like a person trying to shout across a room. If everyone shouts at once, no one hears anything. Bluetooth is more like a group of people who are all constantly changing which language they are speaking and which corner of the room they are standing in, sixteen hundred times every second. It is a technique called Frequency Hopping Spread Spectrum, or FHSS.
Sixteen hundred times a second? That seems incredibly fast. I can barely decide what I want for breakfast in sixteen hundred seconds. So, let us break this down. Where did this idea even come from? It sounds like something out of a spy novel.
It actually is! FHSS was co-invented by the actress Hedy Lamarr during World War Two. She was not just a Hollywood star; she was a brilliant inventor. Along with composer George Antheil, she developed a system to prevent torpedoes from being jammed by enemy radio signals. They used a player piano roll to synchronize the transmitter and the receiver, making them hop between eighty-eight different frequencies. The idea was that if the enemy tried to jam one frequency, the torpedo would already be on a different one before the jammer could catch up.
That is incredible. So, modern Bluetooth is essentially using a World War Two torpedo-guidance system to play my lo-fi hip-hop beats?
In a very direct way, yes. In the case of Bluetooth, it is using that two point four gigahertz Industrial, Scientific, and Medical band. Now, Corn, do you know how many different channels it actually has to hop between?
I remember you mentioning seventy-nine for the older versions, right?
Spot on. In the standard Bluetooth Classic protocol, it divides that band into seventy-nine different channels, each one megahertz wide. For Bluetooth Low Energy, which is what most of our wearables and headphones use now in twenty twenty-six, it uses forty channels that are two megahertz wide. This wider spacing helps reduce interference even further for low-power devices.
Okay, so you have these channels. But if I have my phone and my headphones, and you have your phone and your headphones, how do our devices know which channel to hop to next? If it is random, would we not eventually land on the same channel at the same time and cause a collision?
That is the clever bit. When you pair your devices, they establish a shared clock and a specific hopping sequence. It is pseudo-random, meaning it looks random to an outside observer, but both the phone and the headphones have the mathematical key—the seed for the random number generator—to know exactly where the next hop is going to be. They are perfectly synchronized in time and frequency.
So even if your device and my device happen to hit the same channel at the exact same millisecond, we are only there for six hundred and twenty-five microseconds before we both jump to different, likely non-overlapping channels. That is less than a thousandth of a second.
Precisely. The odds of us colliding on every single hop are astronomical. And even if a single packet of data gets lost because of a collision—which does happen—Bluetooth has built-in error correction and retransmission. It uses something called a Cyclic Redundancy Check to see if the data arrived intact. If it did not, the receiver just says, whoops, didn't get that one, let me try again on the next hop. Because it is happening so fast, and because modern codecs like LC3 are so good at masking tiny errors, your ears never perceive the gap.
You mentioned LC3. We should probably explain that, because in twenty twenty-six, that is really the standard, isn't it? It replaced the old SBC codec that everyone used to complain about.
It did. LC3 stands for Low Complexity Communication Codec. It was introduced with Bluetooth five point two and became the backbone of LE Audio. The magic of LC3 is that it can provide much higher audio quality at half the bit rate of the old codecs. This means the radio is actually on for less time to transmit the same amount of music. If the radio is on for less time, there is less chance of it bumping into another signal. It is like having shorter cars on the highway; you can fit more of them in the same space without a pile-up.
That explains the interference part, but Daniel also asked about the privacy aspect. Why do I not accidentally connect to someone else's stream? I mean, we have all had that moment where we open our Bluetooth settings and see a list of twenty different devices named "Herman's Headphones" or "Living Room TV."
That comes down to the pairing process and unique addresses. Every Bluetooth controller has a unique forty-eight-bit address, which is basically its digital fingerprint. When you pair your phone to your headphones, they exchange security keys using a process called Elliptic Curve Diffie-Hellman. This creates a trusted, encrypted relationship. Even if your headphones see a data packet from my phone on the same frequency, they will ignore it because it is not signed with the correct key and does not have the correct address in the header.
So it is not just about the frequency; it is about the digital envelope the data is wrapped in. If the envelope is not addressed to me, I do not open it.
Exactly. It is like having a thousand people in a room all sending mail at the same time. Frequency hopping is like everyone moving to different mailboxes every second, and the pairing is like having a specific key to only one of those mailboxes. Even if I accidentally look into your mailbox, I cannot read your mail because it is encrypted with a key I do not have. In twenty twenty-six, with the latest security standards, that encryption is incredibly difficult to break in real-time.
I like that analogy. But let us push this a bit further. In a really crowded place like an airport, even with frequency hopping, the background noise must be immense. You have Wi-Fi networks, which we know also use the two point four gigahertz band. We have microwave ovens in the food court. We have proprietary wireless protocols for baggage tracking. How does Bluetooth deal with a channel that is just completely blocked by a strong Wi-Fi signal?
This is where it gets even smarter. Modern Bluetooth uses something called Adaptive Frequency Hopping, or AFH. Back in the early days, Bluetooth would just blindly hop through all seventy-nine channels, even if some of them were noisy. But with AFH, the devices actually monitor the quality of each channel in real-time.
So they are essentially mapping the radio landscape of the room?
Exactly. The headphones and the phone are constantly talking. If the headphones notice that they are consistently losing packets on channels twenty-two, twenty-three, and twenty-four—maybe because there is a massive Wi-Fi router right above that gate—they tell the phone, hey, these channels are junk. Let us stop using them for a while. They mark those channels as "bad" and remove them from the hopping sequence. They keep checking them periodically to see if the interference has cleared, but otherwise, they just dance around the busy parts of the spectrum.
That is fascinating. It is like a driver using a GPS that sees a traffic jam on one specific street and just routes everyone around it. But this is happening at a micro-level, thousands of times a minute. Does this affect the battery life? It sounds like a lot of processing.
It is, but the chips we have in twenty twenty-six are so specialized for this that the power draw is negligible. In fact, by avoiding noisy channels, the device actually saves battery because it does not have to spend energy re-transmitting lost packets. It is more efficient to be smart than to be loud.
You know, it makes me think about the range Daniel mentioned. He said thirty to fifty meters. But in twenty twenty-six, we are seeing Bluetooth Low Energy devices that can supposedly reach much further, sometimes up to a hundred meters or more in open space. Does that increased range make the interference problem worse? Because now your "circle of interference" includes even more people.
It is a trade-off, for sure. Higher range usually comes from better sensitivity or higher output power. But the beauty of Bluetooth Low Energy is that it is designed to be very "quiet" most of the time. It only sends small bursts of data. This is different from the old Bluetooth Classic, which was more like a continuous, heavy stream. By being more efficient with the actual airtime, it leaves more room for other devices. This is what engineers call "spectral efficiency."
I want to go back to the airport scenario for a second. We have talked about the technical side, but what about the actual density? Is there a hard limit? Like, if you put ten thousand people in a stadium and they all turned on Bluetooth headphones at once, would the system eventually just collapse?
There is definitely a theoretical limit. It is called the Shannon-Hartley theorem. It defines the maximum rate at which information can be transmitted over a communications channel with a certain bandwidth in the presence of noise. Eventually, the noise floor—the combined background chatter of all those devices—becomes so high that the signal-to-noise ratio drops below what the hardware can decode. It is like trying to have a conversation at a rock concert. No matter how fast you change languages, the sheer volume of noise eventually wins.
Have we seen that happen in the real world yet? I feel like I have been at conferences where my mouse just stops working.
Oh, absolutely. If you are at a massive tech conference like CES or a high-density gaming tournament, you will often see wireless interference issues. That is why professional e-sports players still use wired mice and keyboards. When every millisecond counts and you have thousands of devices in a small room, even the best frequency hopping can struggle. But for Daniel at the airport, the density isn't quite high enough to break the protocol's back. The physical space is large enough that the signals attenuate—they get weaker—before they can interfere with someone fifty gates away.
It is also worth noting that Bluetooth devices are usually very low power. Your phone is not blasting a signal to the moon; it is just trying to reach your ears. This low power is actually a feature for interference management. Because the signal drops off so quickly with distance, you are really only competing with the people in your immediate vicinity.
That is a great point, Corn. It is the inverse square law in action. If you double the distance, the signal strength drops to one-fourth. This spatial reuse is what allows thousands of people to use the same frequencies in a single building. Your "radio bubble" is actually quite small. In fact, your own body acts as a significant shield. Human tissue is mostly water, and water is excellent at absorbing two point four gigahertz radiation.
Wait, so my head is actually helping my Bluetooth connection by blocking out the interference from the person sitting behind me?
Exactly! Your skull is a natural signal dampener. Engineers call it the "head shadow" effect. It is one of the reasons why some early true-wireless earbuds had trouble staying synced with each other—the signal had to travel through or around your head. But today, we use techniques like Near-Field Magnetic Induction or just better radio placement to solve that.
So, what about the future? We are in twenty twenty-six now. What is the next step for this technology? I have been hearing a lot about Auracast lately. It feels like the biggest change to Bluetooth since it was invented.
Oh, Auracast is a total game-changer. It is part of the Bluetooth Low Energy Audio specification. Traditionally, Bluetooth has been a point-to-point connection. One phone, one pair of headphones. It was a private conversation. But Auracast allows a transmitter to broadcast audio to an unlimited number of nearby receivers. It is more like a radio station than a phone call.
Wait, so like a silent disco? Or those TV screens in airport lounges that always have the sound turned off? I always hate trying to read the captions on those while someone is vacuuming nearby.
Exactly! Imagine you are at the gate, and there is a news broadcast on the overhead TV. Instead of trying to read the captions, you can just open a menu on your phone, find the "Gate B-fourteen TV" stream, and tune your headphones into it. Or, at the airport, the boarding announcements could be broadcast directly to your headphones. You could be listening to your music, and the system would intelligently overlay the announcement that your flight is boarding. You would never miss a flight because you were vibing too hard to a podcast.
That sounds incredibly useful, but doesn't that bring us back to the interference problem? If every gate is broadcasting its own audio stream, aren't we just flooding the airwaves even more?
Surprisingly, no. Because it uses the LC3 codec, which we mentioned is much more efficient, it actually uses less bandwidth. Plus, one broadcast stream serves everyone. Instead of five hundred people each having a separate two-way connection to a server to hear the same announcement, they are all just "listening" to one broadcast. It is much more efficient for the spectrum. It is the difference between five hundred people driving five hundred cars, or five hundred people getting on one train.
That is a really elegant solution to the scaling problem. It is moving from a one-to-one model to a one-to-many model for public spaces. Does it help with latency too? Because that is my biggest pet peeve with Bluetooth.
It really does. Low Energy Audio significantly reduces the delay between the source and the sound. If you have ever tried to watch a movie with old Bluetooth headphones and noticed the lips don't match the sound, you know how annoying that is. That is latency. In the early days, it was over two hundred milliseconds. In twenty twenty-six, with LE Audio, it has dropped to under twenty or thirty milliseconds. That is fast enough that the human brain can't perceive the lag. It is essentially real-time.
So, to summarize for Daniel and our listeners, the reason your Bluetooth works in a crowded airport is a combination of Hedy Lamarr's frequency hopping, smart algorithms that avoid busy channels, unique digital fingerprints that keep your data private, and the fact that everyone is using very low power. It is a massive, coordinated, invisible dance. It is honestly a miracle of cooperation between devices that don't even know each other.
Beautifully put. It really is a triumph of engineering. These devices aren't just shouting; they are listening and adapting to each other. They are being good neighbors in a very crowded neighborhood.
You know, Herman, I was thinking about the "accidental music" part of Daniel's question. Has there ever been a security flaw where that actually happened? I mean, not just a hardware glitch, but a fundamental break in the protocol? I remember hearing about something called "Bluejacking" back in the day.
Bluejacking was mostly just sending unsolicited business cards or messages to people's phones. It was more of a prank than a hack. But there have been real vulnerabilities. You might remember the BlueBorne or BIAS attacks. Those were sophisticated exploits that allowed an attacker to take over a Bluetooth connection or spoof a paired device. But those are very targeted. The idea of just "accidentally" hearing someone else's music because of a crowded room is almost impossible because of the way the packets are addressed and encrypted. You would need to intentionally break the encryption of a specific device, which isn't something that happens by accident.
It is reassuring to know that the "weirdness" of the prompt is actually solved by even "weirder" math and physics. It makes me feel a lot better about wearing these things all day.
That is the theme of this show, isn't it? The deeper you dig into the mundane things we use every day, the more alien and incredible the technology actually looks. We are walking around with sophisticated radio transceivers in our ears that are performing billions of calculations a second just so we can listen to a podcast while we wait for a flight.
It really is. And speaking of things we use every day, if you are listening to this on a pair of Bluetooth headphones right now, take a second to appreciate the sixty-four thousand hops that have happened just in the last minute to keep this audio playing smoothly in your ears. That is a lot of work for a little bit of entertainment.
That is a lot of hops! And if you are enjoying those hops, we would really appreciate it if you could leave us a review on Spotify, Apple Podcasts, or wherever you get your daily dose of weirdness. It genuinely helps other curious people find the show, and it keeps the algorithms happy.
It really does. We have been doing this for over two hundred episodes now, and it is the support from the community that keeps us diving into these rabbit holes. If you want to get in touch or send us your own weird prompt—maybe something you noticed at the airport or while staring at a microwave—you can find the contact form and our full archive at myweirdprompts.com.
And thanks again to Daniel for sending this one in. It is always fun to look at the tech we live with every day and realize how much work is going on behind the scenes just to keep our music playing. It makes the world feel a little bit more magical, doesn't it?
Absolutely. Well, I think that covers the magic of Bluetooth. Herman, any final nerdy facts before we sign off? I feel like you have one more Viking-related fact up your sleeve.
(laughs) You know me too well. Just one. Did you know that the Bluetooth logo is actually a combination of two Viking runes? It is a bindrune of the Younger Futhark runes for H and B. Those are the initials of Harald "Bluetooth" Gormsson, a tenth-century king who united Scandinavia. Just like the protocol was designed to unite different devices and industries. The engineers at Ericsson who developed it were history buffs.
I did not know that. A Viking king's initials are currently in my ears. That is the perfect note to end on. From World War Two torpedoes to tenth-century Viking kings, Bluetooth is way more interesting than it has any right to be.
It really is.
Thanks for listening to My Weird Prompts. I'm Corn.
And I'm Herman Poppleberry. We will see you next week for more deep dives into the strange world around us.
Stay curious, everyone!
Until next time!
You know, Herman, I was just thinking. If we have a king's initials in our ears, does that make us royalty? Or at least honorary Vikings?
I think it just makes us nerds with a podcast and a very specific set of interests, Corn.
Fair point. But a man can dream. Anyway, let's go see what Daniel is cooking for dinner. I hope it's not another "experimental" pasta dish. I saw him buying nutritional yeast and seaweed earlier.
Oh no. Last time he used nutritional yeast and soy sauce... I’m still recovering from that flavor profile. It was like salty cardboard.
Yeah, let's keep the experiments to the radio waves and the frequency hopping. Bye everyone!
Bye!
So, we've talked about the two point four gigahertz band, but I'm curious about the higher frequencies. Does Bluetooth ever go into the five or six gigahertz range like Wi-Fi six-E does?
That is a great question. Historically, no. Bluetooth has stayed in the two point four gigahertz band because those lower frequencies have better penetration through walls and human bodies. Remember, your body is mostly water, and as we said, water is great at absorbing two point four gigahertz radiation. That is why your microwave works! If Bluetooth moved to six gigahertz, the signal would be even more easily blocked by your own head.
Wait, so my headphones are basically trying to microwave my head, but at a very, very low power?
In a very literal, non-dangerous sense, yes! The power levels are thousands of times lower than a microwave oven, but the physics of the frequency is the same. But if Bluetooth moved to five or six gigahertz, it would have a much harder time passing through your skull to reach the other earbud. The signal would be blocked just by you existing.
That makes sense. I've noticed that with my Wi-Fi. If I go into the next room, the five gigahertz signal drops way faster than the two point four. It's like the walls are made of lead for the higher frequencies.
Exactly. It is all about the trade-offs between bandwidth and propagation. Bluetooth chooses propagation and low power over raw speed, because you don't need gigabit speeds to listen to a podcast. You just need a stable, reliable connection that doesn't cut out when you turn your head.
And that reliability is what we're all after, especially when we're stuck in an airport for four hours. Alright, now we're really going. See you guys!
Take care!
One more thing... did we mention the website? I feel like I should say it again.
Yes, Corn. Myweirdprompts.com. It is in the show notes.
Right. Just making sure. The RSS feed is there too for the subscribers who still use dedicated podcatchers.
We got it. Let's go before Daniel finishes that seaweed pasta.
Okay, okay. I'm going. Jerusalem winter, here we come.
It's basically just slightly chilly rain, but we'll take it over the heat of July any day.
True. Very true. Alright, signing off for real this time.
Goodbye!
