Hearing that audio from Daniel really puts things into perspective, doesn't it? The sound of those interceptors in the background—the low rumble of the David's Sling system and the sharper cracks of the Iron Dome—while he is just trying to get some fresh air in a moment of relative calm. It is a stark, heavy reminder of why we do this show. We talk about gadgets and protocols all the time, but for Daniel in Jerusalem, these are not hypothetical "weird prompts." They are the tools of survival. Today's prompt from Daniel is about the humble hand-crank radio. He is asking why, in February of two thousand twenty-six, this piece of technology that feels like a relic from a century ago is still considered the absolute gold standard for emergency preparedness. He is sitting in a reinforced concrete shelter, looking at a high-end smartphone that has become a glass brick, and wondering why a thirty-dollar plastic box with a handle is his only link to the outside world.
Herman Poppleberry here. And Corn, you have hit on something profound right out of the gate. There is something almost poetic, or perhaps deeply humbling, about the fact that when the most advanced digital networks on earth are under strain—whether from physical damage, cyber warfare, or just pure traffic congestion—we turn back to the fundamental physics of the nineteen twenties. Daniel's situation is the perfect case study because he is dealing with the "triple threat" of signal blocking: deep concrete shelters, potential network saturation from everyone trying to call loved ones at once, and the need for absolute, non-negotiable reliability. He is asking about signal penetration, the physics of AM versus FM, and whether modern alternatives like LoRa or ultra high frequency radios have a place in the civilian bunker. It is a deep dive into how waves move through matter, and why "old" does not mean "obsolete."
It is funny because we often think of progress as a linear line where the new thing inevitably replaces the old thing. We think the cloud replaces the hard drive, and five G replaces four G. But in emergency technology, progress is more about building layers of resilience. We have talked about cell broadcast in episode seven hundred forty-five and how that system beats a standard app notification, but radio is the layer beneath even that. It is the bedrock. Daniel mentioned in his email that he feels a bit embarrassed about his level of preparedness sometimes—carrying a crank radio around feels a bit "tinfoil hat" when you are in a modern city. But as he noted, when you hear those booms in the sky and the cellular bars vanish, that embarrassment evaporates instantly. You don't care if it looks like a toy from nineteen eighty; you care if it speaks to you. So, Herman, let us start with the big physics question. Why does a radio signal get into a thick concrete shelter when a five G phone, which is supposed to be the pinnacle of connectivity, just shows "No Service"?
It comes down to a fundamental rule of physics that governs all electromagnetic radiation: the longer the wavelength, the better the penetration and the better the diffraction. To understand this, we have to look at the scale of the waves themselves. Your modern cellular phone is operating on frequencies that are very high in the spectrum. We are talking about seven hundred megahertz all the way up to the millimeter-wave bands used in five G, which can hit thirty gigahertz or higher. Those waves are tiny. At the gigahertz level, the waves are only a few centimeters long. Because they are so small, they are easily absorbed, reflected, or scattered by dense materials like reinforced concrete, metal mesh, or even the leaves on a tree or moisture in the air. They are "fragile" waves.
And the concrete in those Jerusalem shelters—or any modern safe room—is not just any concrete. It is often high-density and heavily reinforced with a dense grid of steel rebar.
That rebar is the real killer for high-frequency signals. When you have a grid of metal where the spacing of the wires is similar to or smaller than the wavelength of the signal, it creates what we call a Faraday cage. It essentially traps the electromagnetic energy or reflects it away. Now, compare those tiny, fragile cellular waves to an AM radio signal. AM, or amplitude modulation, operates in the medium wave band, typically from five hundred thirty to seventeen hundred kilohertz. Notice I said kilohertz, not megahertz. The wavelengths for AM radio are hundreds of meters long. One single wave of an AM broadcast could be the length of two or three football fields. When a wave is that big, it does not even "see" a concrete wall or a rebar grid the same way a tiny five G wave does. It can actually diffract, which is a fancy way of saying it bends around obstacles. It can penetrate much deeper into structures because the material has to be significantly thicker than the wavelength to effectively stop it. To an AM wave, a house is just a small pebble in a very large pond.
So, it is not necessarily that the radio station is "stronger" in terms of raw power—though they are powerful—it is that the physical shape of the wave is more suited to the environment. I have noticed this in my own life. When I am driving into a deep underground parking garage, I can often still hear the AM news station clearly even after my FM station has turned to static and my Spotify stream has buffered to a halt. Why is that? Is FM more like cellular than it is like AM?
You hit the nail on the head. FM, or frequency modulation, usually sits between eighty-eight and one hundred eight megahertz. Those waves are about three meters long. That is much better than cellular, which is measured in centimeters, but it is still much, much shorter than the hundreds of meters you get with AM. FM is generally considered "line-of-sight" communication. It is great for high-fidelity music because the way the information is encoded makes it less prone to the kind of electrical interference from lightning or car engines that plagues AM. But because the waves are shorter, they struggle more with physical barriers. AM is the rugged, slow-moving tank of the radio world. It might sound scratchy, you might hear the hum of the elevators or the fluorescent lights in the building, but the information—the actual voice of the announcer giving you instructions—gets through the noise.
That brings up a great point about Daniel's question regarding other types of radio. He is a tech-savvy guy, and he mentioned LoRa, VHF, and UHF. LoRa has been a huge topic lately, especially with the rise of the Meshtastic project and people building their own off-grid text messaging networks. We saw a massive surge of interest in that during our episode eight hundred eighty-five. Does LoRa have a chance in a bunker, or is it just another "fragile" high-frequency system?
LoRa is fascinating because it uses a technique called "chirp spread spectrum" modulation. It is designed to be incredibly resilient to noise. It can actually find a signal even when that signal is weaker than the background static of the universe. However, physics is a harsh mistress. LoRa typically operates on the nine hundred fifteen megahertz band in the United States or eight hundred sixty-eight megahertz in Europe and the Middle East. That puts it right back in the same physical struggle as cellular. The waves are about thirty-three centimeters long. While LoRa is amazing for sending a text message over ten miles in the open air using almost no power, it still hits a wall—literally—when it encounters deep concrete and steel. If you have a LoRa gateway sitting on the roof of the building and a node inside the shelter, you might get through because of the sheer sensitivity of the protocol. But node-to-node communication from deep underground to the surface? That is a very tough ask. It is not a magic bullet for bunkers.
And what about VHF and UHF? Those are the frequencies used by standard walkie-talkies, emergency services, and ham radio operators. If Daniel had a high-end handheld radio, would he be better off than with his crank radio?
VHF stands for Very High Frequency, and UHF is Ultra High Frequency. UHF is what most consumer walkie-talkies use, around four hundred sixty megahertz. Again, these are relatively short waves. They are actually quite good at bouncing around inside a building—which is why security guards in malls use them—but they do not have the "ground-wave" propagation that AM has. VHF, which is around one hundred forty to one hundred seventy megahertz, is a bit better at bending over hills and through vegetation, but it still requires a significant amount of power to punch through the earth or thick reinforced walls. For a civilian in a safe room, trying to use a handheld VHF radio to hear a broadcast from fifty miles away is going to be much harder than just turning on a cheap AM receiver. The AM receiver is designed to catch those massive, slow waves that are literally hugging the curvature of the earth.
So the AM and FM radio is not just about nostalgia or being "old school." It is about the fact that the entire global infrastructure for emergency communication was built around these specific physical advantages. But Daniel also asked about the network itself. He wants to know why the radio network is more reliable than the cellular network during an actual emergency. I mean, we are told that cell towers have batteries and backup generators, right? So why do they fail when we need them most?
They do have backups, but the architecture is fundamentally different. A cellular network is what we call a point-to-point or a "unicast" system. Your phone is having a private, two-way conversation with a specific sector on a specific tower. That tower has a finite amount of "bandwidth" and a finite number of "slots" for active connections. In an emergency, two things happen simultaneously. First, you have a massive spike in demand. Everyone picks up their phone at the exact same moment to call their family. The network is physically and mathematically incapable of handling that many concurrent connections. It is like a thousand people trying to walk through a single door at once. Second, the "backhaul"—the fiber optic cables or microwave links that connect that tower to the rest of the internet—is vulnerable. If a single exchange point is damaged by an explosion or a cyberattack, or if it loses power and its backup fails, a dozen towers might go dark instantly.
Whereas a radio station is a "one-to-many" broadcast.
It is a giant megaphone. A single AM transmitter can put out fifty thousand watts of power from a tower that is hundreds of feet tall. It does not matter if ten people are listening or ten million people are listening. The transmitter does not "feel" any extra load when more people tune in. It is just pushing waves into the atmosphere. And because those transmitters are often located in rural areas, far from city centers, and have their own massive, dedicated backup generators with fuel supplies that can last for weeks, they are incredibly hard to knock out. You have one primary point of failure—the transmitter—versus the thousands of points of failure in a complex cellular mesh. From a resilience standpoint, the simplicity of broadcast is its greatest strength. It is "dumb" technology, and in a crisis, "dumb" is often better than "smart."
I remember we touched on this in episode four hundred thirty-four when we talked about the sunsetting of older technology like copper landlines. There is this constant push from the private sector to move everything to digital and IP-based systems because they are more efficient for data. But there is a reason the government still maintains these high-power analog sites. If the internet goes down, or if there is a massive cyberattack on the cellular core—which is something people are genuinely worried about in two thousand twenty-six—those radio towers keep spinning out waves. They don't need a handshake, they don't need an IP address, and they don't need a subscription.
And let us talk about the device itself, because Daniel's prompt specifically mentioned the "crank" part. He mentioned the idea of a hand-cranked cell phone. It is a funny image—someone frantically cranking their iPhone just to get enough juice to send a "thumbs up" emoji. But the physics of power consumption make that almost impossible for a modern smartphone. A smartphone is not just a phone; it is a high-performance computer with a high-resolution backlit screen and multiple radio chips—WiFi, Bluetooth, five G, GPS—that are constantly searching for signals. It consumes a massive amount of energy compared to a simple radio receiver.
Right, a smartphone battery is usually measured in thousands of milliamp-hours. If you tried to charge that with a hand crank, you would be cranking for hours just to get enough juice to even boot the operating system.
Precisely. The "energy cost" of just being "on" is too high for a smartphone. A basic analog radio receiver, on the other hand, is incredibly efficient. It does not have a screen, it does not have a processor running a complex operating system, and most importantly, it is not transmitting. It is a passive listener. You can power a radio for thirty to sixty minutes with just sixty seconds of vigorous cranking. That is a trade-off that makes perfect sense in a survival situation. You are converting human mechanical energy directly into the ability to hear life-saving information. Most of these modern emergency radios also use a capacitor or a small, robust lithium iron phosphate battery—LiFePO4—that can sit dormant for years without degrading or catching fire, unlike the cobalt-based batteries in our phones which hate being left at zero percent charge for long periods.
That is a really important distinction. The "readiness" of the device. If I leave an old phone in a drawer for two years, the battery might be chemically dead or swollen when I finally need it. But a well-made crank radio is designed for that kind of neglect. It is the "break glass in case of emergency" tool.
It is. And many of them now include a small solar panel on the top. While it won't charge the battery quickly—especially if you are in a dark shelter—it is enough to keep the radio playing indefinitely if you have it near a window or once you emerge from the bunker. In a shelter situation, the crank is your best friend. But there is another feature Daniel should look for, and that is the "Weather Band" or the "Emergency Alert" mode. In the United States, we have NOAA weather radio, but internationally, there are equivalent emergency broadcast frequencies. Some radios have a "standby" mode where they stay silent but listen for a specific digital header—a "SAME" code—that triggers an alarm. That is incredibly useful if you are trying to sleep in a shelter but need to know the moment the situation changes or an "all clear" is given.
I want to go back to something Daniel mentioned about his "Gleenet" travel router. He uses that to get internet underground by tethering it to a cellular signal or a local WiFi. We talked about those in our "Portable Enterprise" episode. It is a great tool for staying connected to family or doing work, but it relies on a cellular signal reaching it. If the cellular network is jammed or the towers are down, that router is just a blinking plastic box. The radio is the only thing that works when the infrastructure itself is the problem.
That is the "redundancy factor." In engineering, we talk about "common-mode failure." If your phone, your tablet, and your travel router all rely on the cellular network, they are all susceptible to the same failure. If that network goes down, you have zero percent connectivity. Adding a crank radio introduces a completely different failure mode. The only way the radio fails is if the radio station itself stops broadcasting, which, as we discussed, is much less likely than a local cell tower becoming overloaded or losing power. It is about not putting all your informational eggs in one basket.
So, let us get practical for a second. If Daniel or any of our listeners are looking to upgrade their emergency kit in two thousand twenty-six, what should they actually look for in a radio? I have seen some cheap ones at the grocery store that feel like toys, and I have seen some that cost two hundred dollars.
You want to look for three specific things. First, the tuning mechanism. Digital tuning—where you press a button and it scans—is easier to use, but analog tuning—a physical dial that moves a capacitor—is often more robust and uses less power. If you get a digital one, make sure it has a clear signal strength indicator so you know if you are actually on the station or just hearing ghosting. Second, look at the charging options. You want what we call a "quad-power" radio. That means it can run on a hand crank, a solar panel, a built-in rechargeable battery, and standard triple-A or double-A alkaline batteries. Having the option to just pop in some batteries you have stored away is a huge advantage if you are too tired to crank.
And the third thing? You mentioned it briefly earlier.
Shortwave. We haven't talked about the magic of shortwave yet. AM and FM are great for local news. But if things are really bad—if there is a regional power outage or a major conflict where local stations are off the air—shortwave radio can travel thousands of miles by bouncing off the ionosphere. This is called "skywave" propagation or "skipping." A listener in Jerusalem could potentially hear a broadcast from the BBC in London, or a station in Europe, or even the Voice of America, using a shortwave receiver. It is the ultimate "last resort" for information. If you are in a bunker and the local world has gone silent, shortwave is your window to the rest of the planet.
That is fascinating. The idea that you could be underground in one country and catching a signal that bounced off the upper atmosphere from a completely different continent. It really highlights the difference between the "walled gardens" of our modern digital networks—where everything is controlled by a provider—and the "open sea" of the radio spectrum.
It really is an open sea. And that brings up the civilian aspect Daniel asked about. Are there better radios for civilians? For receiving information, no, the AM/FM/Shortwave combo is unbeatable. But if he is asking about "communicating out" of the bunker, that is where it gets tricky. If you are deep underground, your only real hope for transmitting out is a wired connection—like a landline or an ethernet cable—or a very low frequency system, which is just not practical for individuals. Submarines use Very Low Frequency, or VLF, to communicate while submerged, but the antennas for those are miles long and require megawatts of power. For a civilian, your best bet for "communicating out" is actually to focus on the "receiving in" part so you know when it is safe to move to a position where your other devices—like a satellite messenger or a cell phone—will work.
It is about managing expectations. The radio tells you what is happening so you can make informed decisions. It is not a two-way chat tool. I think that is a hard psychological shift for people who are used to the instant feedback of social media. In an emergency, you move from being a "participant" in the information stream to being a "recipient." And that is okay. Sometimes, just knowing the facts is enough to keep the panic at bay.
And the psychological aspect of hearing a human voice over the radio should not be underestimated. During the London Blitz in World War Two, the BBC was a lifeline not just for information, but for morale. There is a warmth and a presence to an analog voice that feels more "real" and more "human" than a text alert on a phone. When you are in a dark shelter and you hear a calm announcer giving updates, it grounds you. It reminds you that there is an organized effort still functioning out there. It breaks the isolation.
We actually covered a similar theme in episode four hundred fifty-seven, the one about the "Pager Paradox." We talked about why doctors and emergency workers still use pagers in two thousand twenty-six. It is because they are one-way, high-penetration devices. It is the same logic as the radio. By stripping away the complexity of two-way communication and high-bandwidth data, you gain massive reliability in the one-way delivery of critical information.
It is a trade-off we have forgotten how to make in our daily lives. We want our devices to do everything. We want them to be a camera, a phone, a map, a library, and a gaming console. But in a crisis, you don't want a "Swiss Army Knife" that might break; you want a tool that does one thing perfectly. A crank radio does one thing: it turns electromagnetic waves into sound. Because it only has that one job, it can be engineered to be nearly indestructible and incredibly efficient.
I also want to touch on the LoRa question again because I know a lot of people are building these Meshtastic networks and thinking they are a replacement for emergency radio. If Daniel and his neighbors all had LoRa nodes, could they create a mesh that works in the shelters?
In theory, yes. If you have enough nodes, you can "hop" the signal from the street level, down the stairs, through the hallways, and into the shelter. But here is the problem: power and coordination. Everyone in that chain has to have their device on, charged, and correctly configured. In a long-term emergency, that is a lot of points of failure. If your neighbor on the second floor forgets to charge his node, the whole "mesh" for the basement breaks. The beauty of the radio is that it does not require your neighbors to do anything. It only requires the broadcaster to keep one big tower running. It is a "low-trust" system in the best possible way.
That makes total sense. Reliability is often inverse to the number of people who have to do the right thing at the right time. So, for Daniel in Jerusalem, the advice is: keep the Gleenet travel router for when things are normal or just slightly disrupted, but keep that crank radio for when the world goes sideways.
And test it! That is the one thing people forget. Every six months—maybe when you change the batteries in your smoke detectors—take the radio out, crank it up for a full minute, make sure the internal battery still holds a charge, and practice tuning into your local emergency stations. Know exactly where they are on the dial. In the dark, under stress, you do not want to be hunting for the frequency. Write the frequencies on a piece of bright tape and stick it to the back of the radio.
That is a great tip. Simple, low-tech, and effective. We have covered a lot of ground here, from the diffraction of long waves to the ionospheric skip of shortwave. It is amazing how much depth there is in such an "old" technology. It is not just a backup; it is a masterpiece of physics-based engineering.
It is old, but it is not obsolete. There is a big difference. Obsolete means it has been replaced by something better in every way. Radio hasn't been replaced in the "reliability in a bunker" category. In that specific niche, it is still the cutting edge. It is the only thing that can reliably punch through a foot of reinforced concrete and tell you what is happening on the other side of the world.
Well, I think we have given Daniel a lot to think about. It is a heavy topic, especially given the context of what he is going through right now, but hopefully, this technical understanding makes the "why" behind the advice a bit clearer. It is not just a tradition or a "prepper" trope; it is a decision based on the fundamental laws of the universe.
And if you are listening to this and finding value in these deep dives into the tech we often take for granted, we would really appreciate it if you could leave us a review on your podcast app. Whether it is Spotify or Apple Podcasts, those ratings really help the show reach people who are looking for this kind of information—people who might be building their own emergency kits and wondering if they really need that crank radio.
Yeah, it genuinely helps. We love doing this show and exploring these "weird prompts" with all of you. Remember, you can find our entire archive of over eight hundred seventy episodes at myweirdprompts dot com. We have a contact form there if you want to send us your own questions, or you can just email us at show at myweirdprompts dot com. We read every single one, and we try to get to as many as we can.
And don't forget, if you want to dig deeper into some of the related topics we mentioned today, check out episode seven hundred forty-five on cell broadcast or episode eight hundred eighty-five on those portable enterprise networks. They provide a lot of the surrounding context for how these systems all fit together. Knowledge is the first step in preparedness.
Our music is made with Suno, which is always a fun part of the production process. We hope everyone stays safe out there, especially Daniel and his family in Jerusalem. We are thinking of you guys, and we hope that radio stays quiet until you need it, and loud when you do.
Stay prepared, stay curious, and keep those radios ready. This has been My Weird Prompts.
Thanks for listening. We will catch you in the next one. Bye!
Goodbye everyone!
