Radio Apocalypse: The GWEN System

Recent developments on the world political stage have brought the destructive potential of electromagnetic pulses (EMP) to the fore, and people seem to have internalized the threat posed by a single thermonuclear weapon. It’s common knowledge that one bomb deployed at a high enough altitude can cause a rapid and powerful pulse of electrical and magnetic fields capable of destroying everything electrical on the ground below, sending civilization back to the 1800s in the blink of an eye.

Things are rarely as simple as the media portray, of course, and this is especially true when a phenomenon with complex physics is involved. But even in the early days of the Atomic Age, the destructive potential of EMP was understood, and allowances for it were made in designing strategic systems. Nowhere else was EMP more of a threat than to the complex web of communication systems linking far-flung strategic assets with central command and control apparatus. In the United States, one of the many hardened communications networks was dubbed the Groundwave Emergency Network, or GWEN, and the story of its fairly rapid rise and fall is an interesting case study in how nations mount technical responses to threats, both real and perceived.

Reliability Through Physics

GWEN began as a patch for a perceived gap in the communications network connecting the country’s strategic nuclear assets — primarily the launch control centers (LCC) of the ballistic missile launch facilities — to the National Command Authority, which is basically the president. Like all strategic communications systems, GWEN was designed to incorporate best practices for surviving the electromagnetic effects of an EMP. But GWEN had another mission.

Ground wave propagation. Source: Electronics Notes

Groundwave propagation is the tendency of certain radio waves to hug the surface and follow the curvature of the earth and is an exception to the general rule that radio waves only travel in straight lines. The earth acts as a conductor below 5 MHz, so radio waves traveling along the surface of the earth induce currents. The induced currents slow down propagation near the surface, curving the wavefront down as it spreads out. There is considerable attenuation of the signal, of course, and careful consideration has to be given to antenna design and construction. But when properly engineered, ground wave propagation systems can be very effective at over-the-horizon communications that do not rely on the ionosphere.

Groundwave propagation requires long wavelengths to work, so GWEN operated in the low frequency (LF) band from 150 to 175 kHz, well below the commercial AM radio medium frequency (MF) band from 530 to 1700 kHz.

GWEN Nodes

A GWEN relay node. Source: Wikipedia, public domain.

GWEN was envisioned as a wide area network of LF relay nodes about 150 to 200 miles apart. Each GWEN relay node communicated to input-output nodes, which were generally located at Air Force bases and other such facilities. The relay nodes were to take command and control messages from the IO nodes and propagate them over the entire network until they reached receive-only nodes, typically the LCC bases. GWEN encoded messages on the LF signals using minimum-shift keying at a data rate of 1200 bps. Messages were encrypted, of course.

Only about 58 of the planned 240 GWEN stations were built between 1982 and the early 1990s, when the program was shut down. GWEN was mostly a victim of Congress, who were unwilling to fund what they perceived to be a Cold War relic after the fall of the Soviet Union. There was also a certain amount of NIMBY-ism with regard to future GWEN sites; with the increasingly popular perception that everything from power lines to cell towers were capable of causing profound biological effects, the prospects of having a powerful radio transmitter that would also be a possible war target in the neighborhood was more than enough reason to mothball the program.

By that time, GWEN’s technology was certainly looking a little long in the tooth anyway, with the rise of the Internet and the proliferation of satellite communications. This may prove shortsighted, though; while there’s certainly a lot of redundancy built into today’s strategic communication systems, there’s something to be said for a simple and robust system that uses basic physical principle like GWEN did.

42 thoughts on “Radio Apocalypse: The GWEN System

  1. “By that time, GWEN’s technology was certainly looking a little long in the tooth anyway, with the rise of the Internet and the proliferation of satellite communications.”

    Fiber optics between key facilities, separate from the internet. Unjammable to boot.

        1. Heck, a windstorm knocked out all non-radio communications to and from multiple towns near here a few years ago when falling trees severed two fiber bundles in separate but key places.
          You don’t even need a backhoe, you just need a bit of wind…

          1. Plus, now the Soviet Maps are public along with Google Maps, Google Earth and newer IMINT or consumer equivalent that I’m not recalling at the moment from an array of gathering sources though not sure who has integrated all together to parse through to determine the most intricate remote sensing detail resource.

  2. Ostracus – the problem with fiber optics is that there is point to point physical infrastructure that can be tampered with or destroyed (SAS mission to take out Iraq’s scud control links). There is a high likely hood competing world powers have identified these fiber links due to the fact that it is quite difficult to conceal the laying of hundreds of miles of buried line. Primary-Alternate-Contingency-Emergency.
    The key advantage of HF or LF frequencies is that the only infrastructure required are the transmitter and receiver. The LF even more so since the natural infrastructure of the ionosphere can be disrupted by nuclear detonations as demonstrated by tests in the pacific.

        1. USA too now!
          137kHz and 472kHz.
          You need to notify the UTC folks that you intend to operate.

          It’s a co-existence thing with powerline PLC control links.
          As a bonus, if you do notify that you are going to operate on those bands, no PLC stuff will be built near you.
          So claim a bit of radio silence for your qth, who knows if you ever want to operate some FT8 on 472kHz and they have deployed PLC near you then.

    1. Yes tube radios will work. No the whole grid at every level of distribution is potentially KO. We will have to order new transformers and wait for Siemens to make more in 6 mo. to years….

      It would be a bit similar to what Puerto Rico is going thru right now, but all the big parts are blown away.

      Meanwhile every nuke in the country will be having problems when backup to run cooling…
      That will really mess things up.

  3. Next do a write-up on Meteor Burst Communications.

    Meteor Burst comms (bouncing ~50MHz signals off of meteroites entering the earth’s atmosphere) only gets about 5KBits per _DAY_, statistically. The comms are, by their propagation path, very secure (only area of reception is an annulus around the master station).
    It works by reflecting the signal off the ionizition cloud (the remains of the meteorite burning up) and lasts between 10mS and 40mS.

    But set off a nuclear air burst and suddenly you have continuous comms.

    1. Amusingly there is SNOTEL
      It’s a meteor burst snow level sensing system in USA.
      Here’s a nice .pdf from NSA explaining what meteor burst communications is.

      We really need to get our FSK441 setup working again at the club.
      Just got 600W 144MHz linear and 250W (should be 600W too, maybe with more drive) 433MHz one.
      Those and tracking yagi setup should be nice for working meteor burst.

  4. Moderate size (tens of kt) fission bombs are nearly as powerful in terms of prompt EMP (short timescale, nanoseconds, effects transistors in ICs) as megaton scale fission-fusion bombs. Generally prompt EMP scales with the square root of the yield with the fission core contributing the majority.

    Not that that makes thermonuclear bombs *not* present an EMP threat. It’s just an interesting tangent.

  5. Solar flare bursts can cause issues also. There are known solar cycles that most in amateur radio have read about and in other disciplines can be found such as economics and maybe even global warming I’ve read.

    Then there are the… who’s sending subliminals to the vulnerable to invest in companies, acts and events that are cronies with fake financial reports and a bunch of ??? and not just laundering are they doing really interests and concerns. I think the not the best not supreme soviets and romans must have hacked the U.S. out, mass murdered forensically clean (until our best and brightest notice again) our unborn, children and elders and that is why performance metrics, values and other quantifiable metrics are pathetic more than ever in our history. Bunch of deviants causing deviations and incidents not required for survival or general healthy, safe, welfare and well being. Reckless endangerment scapegoat drama queens.

  6. If operating in the ultrasonic range or any heterodyne system in the audio range… can you do something like this instructable where you basically can turn anything into a speaker with interferometry using SDR stations (cell, LTE, Wifi, etc.), satellites, drones and power lines:

    Yeah, duh seems like and is strange how controversial compounded and concealed.

    If you can at 100kHz or less or more, why not at any frequency… especially 150 to 175kHz. Especially, if you camoflauge the signal into typical devices emissions in pulse rates and bandwidths most don’t detect on a consumer level and translate especially if recorded to be replayed legible at a later time.

    Laser speakers get more complicated unless you have a great oscillator if I understand correctly… though I may be wrong.

    Laser microphones can be made on instructables also (note this is one of three just on that site with the quick search):

    So, how would the pharma industry be implicated to dose everyone with depressants, amnesics and an epidemic of Alzheimer and dementia as well as other diseases ever since radio and even the telegraph pulse modulation/multiplexing began? Andrew Ure ( and Giovani Aldini (

    I still can’t believe people in main stream media make fake news to deny the Cuban Embassy Assaults that maimed which is poisoning and meets the 18 USC 1111 definition of attempted murder.

    Power lines can be used as carriers. SDR cell phones can be used as carriers. They’re everywhere now. Not just King Fisher and Stingray… there is worse since there is so much bandwidth available now to hack into.

    Man, there must be a bunch of brain damaged idiots looking human and Pan Troglodyte causing diathermy, ECK, EEG, EMG and other not only spooking or scaring people to death with psychotherapautic malicious misleading methods, compounded with narcotics and dangerous drugs.

    There are potential wireless AED systems that can cause the opposite effects.

    Think like a bone conduction headphone using RF and not only sound generation pressure waves. How does a cochlear implant work? What is the neuronal cluster responsible for hearing frequency?

    Duh! I’m amazed how many Operation Paperclip, Mafia Informants, Religious Psycho Sociopath Pedos and others have integrated into the U.S. and other Governments Agencies and Contractor Businesses that brain damage the population and legally can be lethal force prosecuted since deadly force is authorized without a doubt. That must be why they scare everyone so bad and want to take the guns away… i.e. the typical U.S. Constitution required Right kinetic deadly force authorized defense systems where even Senators would have public duels. Now there are a bunch of two faced back stabbing false pretense malicious intent to assault with intent to maim, murder and destroy whatever they can bs’ing everyone to death with bs. Red Alert and Broken Arrow and Worse I say! The brain damaged cult programming red coats are here!

    Why do you think so many international are in executive U.S. roles in the U.S. and World now? They drugged poisoned to death whatever they can every day to be as dumb as they more than mental ill criminally competent are.

      1. Then I wonder about like Jeri Ellsworth did with the microwave scanners (I still have to read about her RADAR work I just found searching her name) and others have with through the wall radar (MIT and other Co.’s) pubicly and marine super HD radars if using multiple in an array since those would be synthetic aperture phased array if designed correctly… doing something with SODAR and fishing super HD resolution sonars. The sonars are in a 100kHz + range. I was just looking at Cabela’s and you can pick up a nice range of different sizes of transducers. Man, some neat gear too with coupling to boat controls and dash board displays and like a microwave oven if collimated not with a horn… maybe a zoom lense antenna or gun multiplexer or maser… huh… scary to me.

    1. “The peak broadcasting power would be 2,000-3,200 W. The UHF antennae at RNs would operate at 20 W and 225-400 MHz.”

      “GWEN would not interfere with commercial television or radio broadcasts, amateur radio operations, garage-door openers, or pacemakers.”

      Thinking in regards to cell or cell cluster sympathetic resonance entrainment range, which is low in regards to current of injury though higher for diathermy effects, looks like there is a potential to disrupt human signals from quite a distance with a clear claim of not disrupting pacemakers at least. :-|) How about heterodyne and pulse train effects?

  7. The whole issue is overhyped in my view. Yes power lines will take a hit but why should generator unit transformers not be protected by their overcurrent devices. Why would not the lines themselves vaporize first before the oil immersed windings in the transformer fuse apart.
    On the other end with miniaturization of electronics the frequencies needed to affect them are on wavelengths on the order of the size of the circuit. I thought EMP power was much less in these high frequencies.

    Anyone know of a serious research publicly available on the risks.

    1. Seems like “Fake News” that is misleading disinformation hacking our minds with deceit. Like Global Warming or Contrails…the weather control and modifications programs as well as chemical and biological pollution from exhaust trails as well as spraying is compounded and concealed with something not accurate or even precise difference.

      1. Most consumer electronics worth a darn was designed with some sort of rapid over-current protection (many zeners can become shunts to ground within .001 ms). Industrial electronics are generally designed quite a bit more robust than consumer electronics, and for the lowest common denominator – Joe blow maintenance guy who just graduated from high school and has done some sort of intro auto/machine shop or basic household wiring. I am not negging those jobs – they need to get done. The thing above with having SDRs in cell phones – the cell carriers are pretty slow to implement new tech. Here in the us, they dont generally want people to jump carriers w/o some large outlay; lock in creates more $$ for them – Why would they allow a device that could be re-flashed so you could switch from GSM to CDMA w/o buying a new device? A few of the posts reek of an alex jones level of emotional (rahter than logic based) attacks with very little actual knowledge of how the underlying systems work.

        1. Sure, I think that is what the fuses, breakers, diodes and metal oxide varistors like you note have been implemented for.

          That is why I think the EMP issues are like Y2K and Global Warming. There is some other motive to drive sales of not require for survival stuff… other than keeping pan troglodyte that looks human and is sub human busy from poaching or looting you and me and others that do not do those criminal acts.

          We know there were Y2K issues with some software. Easy fix, why the media hype? We know there is global warming due to development and releases of heat above the surface of the earth from stuff combusted that was locked in a different state underground and also due to less surface area absorbing the heat and translating into carbon and other elements like nitrogen fixing processes that use the heat. We know there is weather modification using chemical and EMF systems. Those systems can be re-created in a lab and applied on a larger scale. These have been used for longer than my life time. .

          Why would teams be created to break into anything, trained on what is called “The Farm” and have other specialized NSA groups that steal mail and people and implant devices to track and manipulate targets… including firmware and software to collect signals via the emission of signals that blend in the surrounding ambient environment? Maybe even with metglass materials since there are implantable RFID nanoscale chips… oh wait… one radio-isotope atom can technically be used to track.

          Why is Radiation Intelligence (RINT) not well disclosed? Why are more public servants roles, since they are a public trust service, being encrypted and made more secretive? Why are there proprietary devices that the main stream does not know about or are revealed until further leaks or investigation of being present when reverse engineering?

          I have a cheap TDS-520 I am working on repairing. Some have proprietary oscilloscopes that are hundreds of thousands of dollars and maybe more that aren’t even exposed on the market to most…. oh… and that have spectrum analyzers I can only dream about.

          I’m thinking same goes for like SDR’s that have firmware and software you and I can read about and use. Then there is the GNU Radio Companion that can get into more elaborate detail that most of us don’t understand. Then there is assembly based or maybe even C systems that are no way ever going to be exposed that maximize system performance of the latest maybe we can have access or not to some of the components hardware potential to perform Mind Control like noted here: Oh yes, most SDR’s or even heterodyne or superhet systems can be used as a relay at least and many are custom made with even more potential that are not FCC or UL inspected or approved yet used.

          These two devices are the most disturbing though nice to know exists and thankfully not available ANYMORE by there at least: SCANNERS – The DEVICE! and The ULTIMATE WEAPONS & LAB DEVELOPMENT SYSTEM (search the above link and read about that and other neat devices you can still acquire).

          Then remind me why I get “stimulated” and yes… mildly wrong answer that I don’t think is delusional for valid substantiation reasons that I can describe and justify with conclusive evidence more than law enforcement and healthcare along with the courts do on a daily basis without seduction, coercion, intimidation, manipulation, fabrication and grooming youth with narcotics and dangerous drugs to be a victim so I can loot, pillage, plunder and poach what I want because I can mental illness that is a continuing criminal enterprise criminal accomplice.

          This does demonstrate mania if you like that term. Don’t forget those that owned houses and can pay for them… though were broken into, home invaded with interstate domestic violence gang stalkers that intended to maim, murder and serial kill communities off for their ghetto retarded jungle lifestyle looking like they not sub human junkies.

      2. Re: the lithium salt lick statement, there are at least 2 posts at this point that seem to devolve into word salad as the person got more wound up. It reads like a few people I know speak when they are in a manic state. I think one of the worse things that happened for the homeless situation (in my state) was when a prev governor shut down all the state run mental health facilities, turning them loose w/o any oversight. Many of these people are sick and it saddens me to see how they are not getting the medical attention they need.

        1. Very true in regards to the vulnrable adult and child assaults and abuse issues that are more than criminal office neglect of duties.

          Then the homeless victims or even worse lost their jobs desperate mobs go to California or somewhere else, get a name change and appear as someone else in an official position bum rushing the official positions then targeting whomever exposed them for their serious mental illness because they can acquire equipment that only government employees or certified security personal can even clearly know about. Then they are on government tax payers jobs welfare… not just SSA paychecks.

          Kind of like the Axis State actors and all their P.O.W. Camps from WWII and enemy of the State Mafias absorbed into CIA, NSA and FBI roles through being cooperative informant with two or three generations later groomed to be legal looking though not sincerely for U.S. Jurisdiction interests and concerns. Despondent losers roaming the street now with resources to look official and poach whatever they want that is valid…. desperate trying to make anything valid look invalid since that is what they know so naturally.

          This evident in not only the County Courts and Commissions… up to the State and Federal level where even international headquartered say in the Vatican members of alien states are taking over U.S roles and responsibilities.

          Then you have other invalid immigrants acting like their hearsay, educated guesses without quantitative analysis is valid substantiation to determine someone else’s life where they have no jurisdictional bounds over other than by criminal acts to obtain those invalid rights based on fabricated evidence, false pretense and false crimes… Hmm.. no way lean sigma valid roles and responsibilities anyways like in health care, attorney and law enforcement rackets. Where is the Federal Regulation? Those industries that harm humans are self regulated with strange agencies that are frauds from the get go and if not… they were taken over by the three letter agencies criminals and internationals interests I noted before.

          I’m guessing intimidation, coercion, seduction and manipulation that is criminal also with extortion and bribery schemes and if you don’t play along drug poisoning or radiation poisoning schemes noted as treatment. Some even under the guise of counter terrorism, yet the undercover roles perform more criminal acts than their victims to snitch their way out of their own charges that were set aside. Given stolen goods to accomplish their tasks or pogroms or genocide in some cases that are even public if you read into. Where I have found they are the only biker gangs, drug traffickers, panderers of human and human traffickers left in a jurisdiction. I mean dude, where I came from in Allegan… you have Perrigo meth cartel with MExico and China along with what… the Chief of the Fire Department making child porn for everyone to enjoy when they let whomever dump bodies in the Allegan State Game Area dumping grounds! Including vulnrable children and adults who are no way as dump as the miners, war criminals and mafias that sacked the area and hide out in the West Michigan woods and other official looking communities defrauding investors with market hype.

          This isn’t even including out of jurisdictional extra jurisdictional authority issues say the DOD systems gave to who knows who and who knows what they can do with ELINT/SIGINT/MASINT/IMINT/RINT/etc. systems or what pirates are hacking out as we know there are even satellite systems that are military grade that can be hacked out. Yes, manic indeed. No way am I taking amnesics, depressants and drugs to get brain damaged and forget. I am still deep in informing about the issues I have validly observed, am a victim of and still taking down without looking like a scapegoating wuss who has to totally maintain some sort of secret role because I didn’t want to do my job and take risks since I wanted a paycheck and benefits only. .

  8. so much misinformation.

    1) solar flares only damage powergrids because they are a radio-wave with (much) less then 1hz, this is “seen” by the 50/60hz transformers as DC, although this wattage of DC is very low, it causes the transformer to attempt to create a bigger then maximum magnetic field, which at first seems to not harm it, as this energy (loss) is less then the transformer’s max dissipation, BUUUT this causes the transformer to not be able to increase field strength along with the 50/60hz AC, which basicaly means the AC component is short-circuited, and this 50/60hz AC is coming from a multi-giga-watt powergrid! the solution is to isolate DC from flowing into the transformer in the first place, the 50/60hz can keep on ticking. they are slowly adding this to substations near where i live.

    2) the above was for medium solar flares, note how i did NOT mention damage of consumer goods, any damage would only be from nearby substation issues. large flare just recently hit us in 1855 so we should be okay for another loooooooong while. gamma-ray bursts are totally different and poisn the air, land, water, food, people, and the ionosphere at varying speeds and effects and are even less common.

    3) high-altitude nuke explosion induced-EMP is totally different, its waaay stronger but is limited to less then a blink of an eye. its effects may be very varied. it covers a much smaller area then a solar flare.

    4) a serious EMP could knock out SOME moving vehicles, rendering the highways accident-gridlock zones, but this would depend on car’s make, model, distance from EMP source, and relative orientation to the recieved wave or its reflections.

    5) as for starving public, new trucks can be driven in and then the food and water already in the fields and warehouses can be delivered until permenant trucks purchased. there will be plenty in other regions of the world.

    6) i believe, or at least like to believe (so i can sleep at night) that nuke-power plants are hardened against EMP, as they normally survive lightning strikes, which produce EMP along with other energys…

    7) in 1000 years from now there’ll be another 1855 and 99.999% of us will die off, but dont worry, we will have colonized Mars and the new MARsTIANS will re-colonize earth, eventually.

    1. Great info.

      I hope there is more than 0.001% of our genetics left in 1,000 years. Never know with all the GMO, carcinogen, mutagen, multigen and teratogen activity. Time to clean up sooner than later.

      I think we can have dirty power generation, nuclear recycling and disgust underground more in the future also to clean up and be more hardened. Unless the ground is hotter in some places… then maybe geothermal can be considered… seems we can clean up effusia more with underground systems easier. Reminds us more regarding what we waste into the atmosphere also IMHO.

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