EMP Protection for Two Way Radios

A new episode of The Two Way Radio Show Podcast is out! We discuss the potential for damage from electromagnetic waves and how to protect your radios from an EMP attack. But Is all this just the stuff of dramatic disaster movies and paranoid preppers, or is it actually a valid cause for concern? Listen now!

Comments and feedback are welcome and could get you some swag if they are read on the show!

TWRS-171 - EMP Protection for Two Way Radios

Show Notes:
TWRS-171 - EMP Protection for Two Way Radios (buytwowayradios.com)

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Back in the Cold War days I was involved with uk civil defence. In my loft space I had a large aluminium EMP proof case containing …… I do not know. When the Berlin Wall fell, a few months later it was crushed without me ever knowing.

I find the American obsession with surviving war totally laughable. I’m sorry, but people are really building nuclear bunkers, and wrapping their Baofengs in foil and burying them in the garden? The trend seems to be people want dirt cheap radios, costing as little as possible, but are now trying to keep them working after somebody drops a bomb? Really? If I advertised a radio here in the UK, saying buy this radio, stick it in an EMP enclosure and hide it away just in case a war started I’d be on National TV as a loony, and the ■■■■ of a million jokes. Does average Mr America believe EMP damage soon is this likely? It makes America and Americans look a bit er, xenophobic and panic stricken. I’ve mentioned ‘go bags’ to people here and nobody has ever heard of this kind of protectionism. The vast proportion of UK residents live within overnight fallout distance from a USAF air base, and even our loony left politicians don’t even talk about bombs. Sorry guys, but you really are suffering from paranoia.

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Perhaps insults should be left for off-forum communications.

Insults? Let’s not go woke. My point is that we have got to the stage where hobby users, because I don’t see business users talking about the doom and gloom that is really approaching paranoia levels. Perhaps my a British levity around all things bad is not appreciated, and for that I apologise. Firms in the US are making end of the world products and people are buying them. The magnitude of EMP is such that we could line a Jiffy bag with tin foil meant for turkeys and sell it as a product to put your Baofeng inside to save your radio. In most countries we don’t have ‘preppers’. In the UK you will sell your lined Jiffy bag if you advertised it for keeping your car key fob safe from the crooks with receivers to steal your car, but market it as a product for EMP protection and you’d go bust. I’m old enough to remember the Cold War, and how close we came. Nothing now reminds me of this. I’m sorry folks but the US has gone mad. I had to google SHTF which I heard in the podcast. If, people believe a nuclear war is about to happen, I’d suggest people might like to engage their brains. Our press think every American has at least two or three metal ammo boxes under their beds, so the entire point of using a Faraday based screen is to prevent RF getting in or out with a low resistance path surrounding the devices being protected, with any gaps smaller than the wavelength of the field. With an all metal ammo box this is pretty simple to achieve.

If you really want to protect your equipment it’s not that hard. The trouble is when you do protect it, what will you use it for? No electricity to charge batteries, no repeaters, so you can talk to other like minded souls within a few miles of you. What exactly would you be talking about ? EMP devices, detonated in the air mean any protected devices wont be that useful as the services in general within the area wont be working, so comms isnt that useful.

I’m saddened nobody is seeing the funny side of this discussion. Keeping in mind what training I had in the 80s, I should be wrapping radios up, and I have hundreds in boxes in the store. I suspect two way radios could also stand in their warehouse and be loading all sorts of their stock into EMP proof storage. From the undercurrent of the podcast, I suspect they are not.

Viewed from abroad, the people in the US have been viewing Mad Max as a documentary. Nothing I read makes what they do even understandable. It’s brilliant of course for the people who build nuclear bunkers!

No offence is intended against the majority of folk who have balanced views on the world, but Dr Strangelove is alive and well it seems.

I am probably the least woke person you would ever meet. I was in the military during the 70’s and visited the UK several times. As far as being prepared, well, maybe our country has a few different thing to be concerned about. Two years ago the state I live in had the largest wildfire in our history. I live in a small mountain town. The utility company shut off the power for safety reasons and it stayed off for a week. We were in a evacuation “warning” area as were my oldest daughter and her family . after a couple of days the cellular service went down. We were able to keep in touch with our family using GMRS radios. Had we not been prepared with store food and water we would have been in a bad way. When we were forced to leave our home by mandatory evacuations orders we were able to communicate with the family until we were out of the mountains and had cell service.

Since that time The utility company shuts off power when there are high winds multiple times. One of those times we, again, lost cell service. During those times without power there were unscrupulous people breaking into houses and looting homes. Not much of this made the news. So when you refer to people who discuss EMP protecting they are the ones who prepare for the other stuff as well. They are the people that might be able to help others whether it be during wildfires, earthquakes, hurricanes, and yes, even something as outlandish sounding as an EMP.

I read your replies and your threads and I enjoy your humor. I was told once that every time someone makes a joke there is a little bit of truth in it. This post was not the first time you have questioned our sanity over here, even if in jest. Go ahead and count me with those loony Americans.

Thanks for taking the time to reply, and I do understand the natural disaster point. Oddly, we did actually have an official from every regional area of the UK tasked as the emergency planning officer, who liaised with CB groups, hams, St. John ambulance and the Red Cross, plus marine groups to offer emergency services for natural disasters, and they did get used, but this person’s status was reduced drastically from the Berlin Wall removal. Councils now have this job still on the books, but staffed by recent graduates at just over McDonalds pay levels, often a shared role. If we have real disasters, it will go badly wrong and the links to volunteer groups have largely gone, and are untested. When the US were stationing weapons all over the UK we had big very loony ( in my opinion) groups opposed to it, but now these bases are closed, even these groups have virtually shut up shop. Nobody under 25 has ever heard of them. Maybe it is the size of the US that makes these things more vital, but I take the emergency point you made and see how that fits in.

I suppose, jokes out of the way, I wonder why the massive threat of the time up to the Berlin Wall collapse hasn’t reduced concern. I accept that the world would make the detonation of a bomb by radicals possible, but the delivery systems mean it’s world powers of super size who are the only real threat to all of us. People who live in very sparsely populated areas were not targets anyway, unless near one of the ‘problems’ like armed forces bases and the nuke sites. The radicals wouldn’t focus on those areas anyway, and if you live in a city, you seem to also be the kind of person who doesn’t dig holes and build up arsenals of weapons.

What we outsiders see is a powerful country with a lot of people upset about the way the world is, including their own government. You have laws allowing one person to own more weaponry than the county I live in has! We see the crazy ones use it too, then we see others so worried about war doing their stuff. I keep trying to think how we would feel if our country had these thinks and I can’t. I see a country scared of war but quite keen to protect themselves from one by making other people think they wan5 to start one?

That is an outsiders viewpoint based on what I see and read. Of course I have no way to know how common these views are, or what an ordinary American even is now. One of my ex-students and good friend lives in California. Over ten years he has changed, drastically. He now thinks differently.

I don’t want to annoy anyone, so I’ll not comment any more on this kind of stuff because I don’t want to annoy you folk, but now it’s spreading to two-way radio and their customers are buying EMP proof gear, that really worries me. It’s good for sales of course, so they’re giving customers what they are asking for so I don’t blame them, but the people buying the stuff concern me. If people have a genuine concern that makes them buy products for the doomsday scenarios, with nukes flying everywhere, something is wrong. Should us Brits worry about what is going on in our USAF bases. Nobody does at the moment. You guys on here I think are level headed and normal, whatever that means, but if you do see nuclear issues as likely and possible, and are not nutters, then us outsiders have missed the signs and signals you have used to form your opinions. Probably just a cultural thing so we can’t really ever understand each other. Keep safe folks. I’ll leave it now.

To be fair, prepping is certainly not an “American obsession”, nor is it an interest limited to America alone. An unofficial estimate of the size of the prepper community here in terms of percentages is well in the single digits. However, considering current events, it’s not surprising that interest in disaster preparedness is probably growing. It’s a large country with vast expanses of rural areas, particularly in the west. Many have experienced localized disasters first hand, and those who were fortunate enough to prepare beforehand were quite thankful they did.

It is certainly not the exclusive domain of Americans, either. I understand Australia has a fairly large prepper community, as does New Zealand. This is certainly understandable, as most of Australia is pretty wild territory and requires some prep and survival skills to navigate and manage. New Zealand has had more than their share of disasters and emergency events, so it’s no wonder their prepper community exists.

Sure, paranoia does exist in the prepper world, but the assumption that all preppers fall into that category is a bit of an overstatement. Having ridden through a number of hurricanes myself, I can assure you that there is nothing wrong with being prepared for “the big one”.

As I said in the podcast, I’m not as concerned about a nuclear “doomsday” scenario, but I think that natural or cyclical events such as extreme solar flares, which have and will occur from time to time from a scientific point of view, and which have been proven to cause some disruption historically, are practical reasons to at least consider a preparedness plan.

After all, as the sayings go, an ounce of prevention is worth a pound of cure. Better to have it and not need it, than need it and not have it.


I really enjoyed episode 171 and I wanted to share a few thoughts.

As a reminder, the way that radio communications work is that a traveling electromagnetic field passing through an antenna induces a small voltage in the antenna that is detected by the receiver.

In the case of an EMP, the traveling electromagnetic field is so powerful, and has such a wide bandwidth (being an impulse), that it induces a large voltage in all electronic devices and components that it passes through. If these induced voltages are weak enough, they might just disrupt the device enough that you need to reset it, but if they are strong enough, they can damage components within the device.

Another reason why we are more vulnerable to this now than we were 50 years ago is that our electronics have become more delicate. MOSFET transistors are more susceptible to damage than bi junction transistors are, and bi junction transistors are more susceptible to damage than vacuum tubes are. Relays, such as those used in telegraph lines, are the least susceptible to damage from a sudden brief voltage spike.

Therefore, your brand new radio with a computer inside is the most susceptible to an EMP, while your older solid state radio is a little bit less susceptible, your 70-year-old tube radio is much less susceptible (but may prove more difficult to power if the grid is down), and your hundred-year-old landline telegraph set is pretty much immune. Your spark gap transmitter and your cat whisker crystal receiver are also likely to still work after an EMP, though you may need to adjust the cat whisker.

Another Faraday cage that many people can use in a pinch if we happen to receive a warning about an impending event is their washing machine or dryer. Also, remember to protect all important electronics, including things like the charging controller for your solar cells and an extra battery charger and set of batteries.

I would also like to point out that there are some other low tech communication options that could prove very useful in a SHTF situation.

People who know Morse code can communicate up to a few miles using whistles, and whistles are essentially immune to damage from an EMP.

There are also visual signaling methods, such as the heliograph or the movement of flags or lanterns, combined with a set of binoculars, that could prove useful in such a situation. Many interesting details can be found in the 1910 “Manual of Visual Signaling of the US Signal Corps.” at https://archive.org/details/manualvisualsig01corpgoog

The curious reader may find the table of abbreviations on page 46 somewhat amusing, proving that “text speak,” including the use of the letter u for the word you, the letter r for the word are, and the letters ur for the word your, is not new.

Between the usefulness of whistles and visual signaling, I would submit that learning Morse code is an excellent investment for preppers.

Thank you again for your wonderful show,


PS I still think you should do a show on itinerant business band frequencies. See my email from Oct 14, 2021.

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I think that Morse is actually a good and fairly easy comms protocol to learn and can be used as said, so many ways. I guess I need to accept the premise the preppers put forward - because if their skills and preparations ever are needed, the joke is on me.

We’ve actually had a popular BBC series (12 years, I think so far) have a story based around a group of preppers on a tropical island - flawed to make the story work (as in the people inside could hear through the ventilation system - making it not really much good keeping things out.

I was thinking about the sturdiness of radios - and I must admit I’m getting a bit paranoid when in this cold dry spell, I walk across the office and when I touch metalwork, there’s a static crack. Touching a MacBook, or one of the radios, I usually turn them on, just to check I’ve not zapped it. So far, I feel I’ve been lucky. Static damage was not something I even thought about when first doing radio in the late 70’s.

Lol. Being from England, laughing at us Americans. Prepping is exactly why we’re still not the “Colonies”. Besides there isn’t anyone who wants England. Really think about the simplest comparison of the land value. England lost it all to a bunch of “Preppers”, not even real soldiers. It’s our heritage.

Well thanks Dan, welcome to the forum and for searching out my post, and of course, to not having a sense of humour! Why don’t you tell us Brits a little about it so we won’t think it’s completely odd? Sadly, at the moment, lots of foreign folk do want England - and it’s a big problem.

Right! When working at a chemical plant at the Yakima Reservation a service tech for an office printer stated he did not have any cell service there. I told him we kept a fire going out back with a wool blanket if he needed to call the home office in Seattle… LoL
Drums are also immune to EMP.
Telegraph nay not be exempt from damage in the case of a CME from the sun, however. The Carrington event in the 1800’s pointed this out.
Oh, and large primates here in the Pacific Northwest utilize tree knocks, banging large branches on tree trunks. :wink:

Set up your station on a sheet of well grounded aluminum ground plane perhaps? That may help with the static discharge.
I hear of people using my metallic window screen for ground plane when portable. That may also work under your gear on a picnic table if operating portable. Connect it to a ground rod.