Category Archives: Preparedness

Steve searches for a USB-powered battery charger for solar recharging

Many thanks to SWLing Post contributor, Steven Crawford, who writes with the following inquiry:

[I’m searching for] good quality USB powered battery chargers for AA and D size rechargeable batteries.

Wall outlet chargers are common but quality USB powered battery chargers appear much less common…less common than the packable solar panels with USB ports such as Anker’s, that could be used to power them. Ideally the charger should handle Nicad’s, NIMH and Ii-on but have standardized on AA, AA + D adapter sleeves, and D batteries for my storm supplies.

If I understand correctly, you’re searching for a good qualityUSB-powered battery charger that supports multiple battery chemistries (nickel-cadmium, NIMH and lithium ion) so you can recharge AA, AAA and D batteries with a portable solar panel.

I’m hoping SWLing Post readers can offer some suggestions.

I’ve also looked into this type of charger for both Ears To Our World and my own personal use when off-grid in the summer. I’ve never found one that truly supports all of the battery chemistries you mentioned. The one I’ve used (an EBL) works quite well, but only supports NiMH AA and AAA batteries. As you mentioned, you can use D cell sleeves with the AAs.

EBL makes a number of USB chargers that can be found by searching Amazon. This one–an EBL Quick Charger (affiliate link)–can recharge NiMH batteries within 40 minutes and I’ve personally used one. I’ve been pleased with EBL batteries as well.

I never use nickel cadmium rechargeable batteries at this point, so really don’t know what’s available on the market.

I have found that there are a number of USB-powered lithium battery chargers, but typically for specific lithium cell configurations like 18650, 16340, 14500, 26650, etc. Some of these inexpensive chargers have magnetic contacts that can fit almost any battery type and on Amazon and eBay they claim to recharge multiple battery chemistries, but frankly I’m quite skeptical. These $9 devices don’t seem to have a way of detecting battery chemistry, thus I’m not sure how they would adjust the charging cycle accordingly. Perhaps I’m incorrect in this assumption?

Other than using Powerfilm solar NiMH battery chargers (I can recommend these) which are incorporated in their folding panels, I’ve never charged batteries directly from a solar panel. Typically I have a 9ah or larger 12V battery floating between the PV panel and the charger.

I’ve found that using a 12VDC charger–like this–that’s pulling power from a 12V battery is simply a little more efficient, faster and reliable than charging directly from a small PV panel. Since I always have 12V batteries on hand when off grid, it’s a simple solution for for my system.

Post readers: do you have any USB-powered battery charging suggestions for Steven? Please comment!

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Everyday Carry: My EDC packs and radio kit

SWLing Post contributor, Matt, writes:

Thomas: I know you’re a self-proclaimed pack geek and so am I! You published a photo of your EDC pouch in a post last year. Just a teaser really! What is that pouch and I assume you have a larger carry bag as well? Can you provide more details? I’m ever revising and honing my own EDC pack. Any details would be appreciated.

Thanks for your question Matt!  Besides radio, you’re bringing up on one of my favorite topics: packs! You may regret having asked me!

Yesterday evening, I snapped a few photos of my EDC (Everyday Carry) bag and the pouch you’re referring to. Your inquiry is prompting me to consider publishing a more detailed look at my EDC gear–especially since radio is such an important part of it.

I do carry a larger EDC bag at all times. Typically, this is the Tom Bihn Pilot:

For years, I carried a Timbuk2 messenger bag, but it didn’t have the type of organization I prefer in an EDC bag. My EDC bag must be rugged, water resistant and accommodate my 13″ MacBook Air while still having enough depth to comfortably fit the rest of my gear.

I’ve been using the Tom Bihn Pilot for almost a year and have been very pleased. The Pilot is an investment to be sure, but (like Red Oxx) Tom Bihn construction quality is superb and comes with a lifetime warranty.

It’s amazing how much gear will comfortably fit inside without making the bag bulge. The Pilot also has a dedicated water bottle pocket in the middle of the front panel. While I do carry water, it primarily houses my never-leave-home-without-it Zojirushi Stainless Steel Mug (affiliate link) which is filled with piping hot dark roasted coffee!

I also use the water bottle pocket to hold full-sized handled VHF/UHF radios. It accommodates either my Kenwood TH-F6, Yaesu FT2D, or Anytone AT-D868UV perfectly. Indeed, all of the front pockets will accommodate an HT since the zippers terminate at the top of the bag. Long antennas can easily poke out while the zipper still seals 99% of the opening.

The Pilot has one main compartment that houses my 13″ MacBook Air laptop.

The Pilot laptop compartment is spacious and has two built-in pockets opposite the laptop sleeve: one of these pockets (the one on the right in the photo above) holds my EDC pouch, the other holds first aid supplies, an Olight SR1 flashlight and Nitecore LA10 latern (affiliate link). My laptop is in a TSA-friendly Tom Bihn Cache.

While the Tom Bihn Pilot is the bag I use most days, also use a Red Oxx Micro Manager and–when I need 25 liters of capacity–the Tom Bihn Synapse 25.

I pack most of my EDC gear in pouches, so moving from one bag to another takes me all of one minute.

My EDC pouch is the Maxpedition Fatty Pocket Organizer (affiliate link). I love this pouch because it’s incredibly durable, affordable and opens like a clam shell to lay flat.

Everything has its place. Not only does it hold my Yaesu VX-3R handheld, but also a multi-function knife, a Leatherman Style PS tool, clippers, earphones, multi-bit screwdriver, USB stick, notepad, spare VX-3R battery, a mini first aid kit, titanium spork, and much more! Someday I’ll pull the whole thing apart and note each item.

Why do I choose the Yaesu VX-3R? First of all, it’s compact. This HT is so small it’ll tuck away anywhere. Not only is it dual band, but it’ll also receive the AM broadcast band (even has a little ferrite bar inside), the shortwave bands, and the FM broadcast band.

The mini rubber duck antenna will work in a pinch, but I also carry a flexible Diamond SRH77CA in the floor of the Tom Bihn Pilot’s main compartment.

When I attach the Diamond antenna, it significantly increases the VX-3R’s capabilities.

While the VX-3R does cover the HF bands, don’t expect amazing performance. Selectivity is poor, but sensitivity is adequate. For a shortwave antenna, I carry a short length of coax: one end is terminated with an SMA connector, the other has the center conductor exposed.

I also carry a short alligator clip cable which I clip to the exposed center conductor and then to a length of wire. The end result is a very cheap, flexible and effective portable HF antenna!

Someday, I’ll take everything out of my EDC pack, inventory the contents and publish a post about it. Somehow, that’ll please my inner pack geek! I’m overdue a review of the Tom Bihn PIlot and Synapse 25.

Post readers: Do you have an EDC pack built around a radio? Please comment and include links to your favorite gear!

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Guest Post: Hans reviews the Freeplay Lifeline and Unity self-powered radios

Many thanks to SWLing Post contributor, Hans Johnson, who shares the following guest post:


Irma-induced Radio Reviews

by Hans Johnson

The primary disaster we face here in Naples, Florida, is hurricanes.  Naples had been spared for over a decade until Irma.  So while I had prepared, I had not needed my supplies or equipment for quite some time.  This included the radios.

I went into Irma with two Freeplay solar and windup radios, a Unity and a Lifeline.  I got these radios probably over a decade ago.  As part of some work I was doing with VT Communications (now Babcock), I was involved with a radio project called Sudan Radio Service.

Both of these radios were being given to listeners as part of this project.  I wanted to have a better understanding of what they faced.  I had some conversations with Freeplay in London, explaining who I was and why I wanted these radios.  During a visit, I was able to purchase both sets with the proviso that I not sell them.

I checked them both out at that time with my focus being on shortwave as that is how Sudan Radio Service was then transmitted.  They were ok at picking out the strongest stations but that’s about it.  I never really needed or wanted to use the radios day to day.  And then Irma struck.

We left Naples on Saturday when we received a mandatory evacuation notice.  The storm struck on Sunday and we returned on Monday.

We were spared.  Many lost everything.  Some lost their lives.  We had a lot of trees down and some roof damage, but nothing substantial.  But we had no power.  Water had to be boiled.  Sewage was backing up in places because the lift stations had no power.  The stop lights were out (this was a real danger, many did not treat them as four-way stops and just blew through them.  But you never knew who it would be.)  A curfew was in place.  The cell phone system was in really bad shape.  I could not call or text my brother across town, let alone get access to the Internet via cell.

This link will give you an idea of what we came back to.  I am the guy sawing wood at 1:47.  (Lesson learned, have two chainsaws in case yours blows a gas line):

http://abc7ny.com/weather/watch-josh-einiger-reports-from-naples-florida/2391120/.

I had blown up some air mattresses before the storm so we slept on them on the screened porch.  I saw the Milky Way from Naples for the first time.

We wanted information and also a bit of entertainment.  Television was out of the question.  The HDTV stations are hard to receive with a great antenna and set in the best of times where we live.  So a battery-operated TV would have been a waste.  Radio was the only game in town, so it was time to put the emergency radios in service.

Sudanese Listeners Receive Unity Radios (Source: Lifeline Energy)

Both of these analogue dial sets cover AM, FM, and shortwave.  The Unity covers 3-22 MHz, the Lifeline just goes up to 18.  The former covers the old American AM band and the latter the new one.   The Unity uses a whip antenna and has a fine tuning knob.  The Lifeline has a bendable wire that fits into the carrying handle and came with an alligator clip and a length of wire.

Ideally, one would be listening a set that has been charged via the solar cell or listening with the set in the sun.  The last place I wanted to be was in or near the sun.  Trying to charge the set and then listen to it is difficult in practice.  It seems that the ratio was about one to one.  15 minutes in the sun would get you about 15 minutes of immediate listening.  It doesn’t seem that the batteries will hold a charge for long periods of time.  I could not charge them during the day and expect to turn them on the next morning, which was the peak time of day for radio to be transmitting local information.  The ratio for using the hand-crank was better, but I grew tired of cranking quite quickly.

I was interested in local stations, so shortwave was not a factor.  We only have a few local AM stations in Naples and I could not receive them (Irma knocked off or damaged a number of stations.)  I tried FM.  Even with the antennas retracted, both sets were overwhelmed by the local stations with certain stations bleeding through over much of the dial.  I could receive some strong, local stations.  With the outlet at Marco Island off and the other apparently on reduced power, receiving NPR was out of the question.

Given how many sources of information I was cut off from, my flow was greatly reduced.  My ignorance increased and learning vital information was hit or miss.  A neighbor told me about the boil order.  Passing on information was difficult.  When we got power I wanted to tell my brother, but the only way to inform him was to drive to his house.

One result was that I put these sets away and broke out my old Sony

ICF-7600GR and used it instead.  I guess I could have used it until I ran out of AA batteries.  I had plenty on hand and can easily afford them.  But that is hardly the case in Southern Sudan and many other places.

The Lifeline came with a few stickers on it that I could not read when I got the set.  Now that Goggle translate is so good I can read them.  They say in part:  “Everyone has the right to receive information,”  “Everyone one has the right to search for, receive, and deliver information.”

The real result of the test was a greater appreciation for how good I have it in many ways.  With regards to information, I have many sources and can readily receive it and pass it on.  It increased my respect for services like Sudan Radio Service and how important they are.  But most especially, I have a much greater admiration for listeners using these sets and what is surely their perseverance, patience, and determination to get information.


Many thanks for your field report of the Freeplay Lifeline and Unity, Hans!

I’m happy to hear you had no serious damage post-Irma. So many in the SWLing Post community have been affected by hurricanes this season.

I have never, personally, reviewed either of these Freeplay units–both are now discontinued and have been replaced with other models at Lifeline, I believe. As you state in your post, these radios are only available to humanitarian organizations. Through Ears To Our World, I have considered acquiring Lineline Energy (Freeplay) radios in the past. However, their radios tend to be rather large in size–we tend to go with smaller receivers that can easily fit in suitcases. In the past we’ve been very happy with the Grundig FR200 (Tecsun GR-88). 

The Lifeplayer MP3

Last year, we did purchase a Freeplay Lifeplayer to test. The hand crank charging mechanism is very robust, though quite noisy. The radio is digital, but performance is mediocre and tuning couldn’t be more cumbersome (5 kHz steps, no memories, only a couple of band steps.  Tuning to your favorite station could literally take a couple of minutes, depending on where it is on the band. When you turn off the radio (or it runs out of power) you’ll have to re-tune to the station again. That’s a lot of extra mechanical wear on the encoder. The real utility of the Lifeplayer is the built-in MP3 player and recorder–a brilliant tool for rural schools. Also, it’s robust and can take abuse from kids much better than other consumer radios.

Your main point, though, is spot-on: these radios serve their purpose, but we radio enthusiasts are incredibly fortunate to have much better grade equipment to take us through information backouts.

Thanks again for your review, Hans!

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Amateur radio: “Playing Key Role in Puerto Rico”

 

(Source: NBC News)

When things went dark and quiet in Puerto Rico, a cadre of amateur radio operators became a lifeline on the island.

About two dozen amateur radio operators on the island helped police and first responders communicate when their radio networks failed completely. Some of the radio operators, or hams traveled on trucks to provide communications to the power company, PREPA.

“It’s a less than ideal solution, but it works and that’s the essence of amateur radio – make it work,” said Tom Gallagher, CEO of the American Radio Relay League, the national association for amateur radio.

Now the ranks of operator are about to get reinforcements.

At the request of the Red Cross, the league planned to send 50 radio operators into Puerto Rico with “enormous” radio gear in water proof containers, their own power supplies, new generators and solar arrays. The crew and equipment were to leave Thursday from Atlanta.

Their job, once set up and in place, will be to be the communication pipeline for the Red Cross Safe and Well program, helping people on the mainland trying to connect with loved ones on the island or get news of their status.

“You can relieve a lot of misery by telling people their relatives are okay,” said Gallagher, whose call sign is NY2RF.[…]

Continue reading the full article at NBC News…

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EMP Radio Preparedness Primer 1: Understanding the Electromagnetic Pulse

Will modern portable radios survive an EMP? Likely not without protection.

Here on the SWLing Post we tend to cover topics related to shortwave radio, ham radio and international broadcasting. We also cover an array of other topics our contributors and readers find appealing.

Lately, I’ve noticed an uptick in one particular question–at least, variations of it–from readers and people who found our site searching for emergency/preparedness radios:

What radio can survive an EMP?”

or

“How could I protect a radio from an EMP?”

What is an EMP?

In case the term EMP is new to you, check out this explanation from Wikipedia:

An electromagnetic pulse (EMP), also sometimes called a transient electromagnetic disturbance, is a short burst of electromagnetic energy. Such a pulse’s origination may be a natural occurrence or man-made and can occur as a radiated, electric, or magnetic field or a conducted electric current, depending on the source.

EMP interference is generally disruptive or damaging to electronic equipment, and at higher energy levels a powerful EMP event such as a lightning strike can damage physical objects such as buildings and aircraft structures. The management of EMP effects is an important branch of electromagnetic compatibility (EMC) engineering.

Weapons have been developed to create the damaging effects of high-energy EMP. Misleading or incorrect information about such weapons, both real and fictional, have become known to the public by means of popular culture and some politicians’ claims. Misleading information includes both exaggeration of EMP effects and downplaying the significance of the EMP threat.

In short? A strategic EMP could cripple our electrical grid and potentially many other electronic and digital devices.

Most of us are concerned with wide-spread disruptions from electromagnetic pulses originating from:

  • Man-made atomic weapons
  • Natural occurrences, like solar flares/storms

A solar flare erupts on the far right side of the sun, in this image captured by NASA’s Solar Dynamics Observatory. (Image: NASA/SDO/Goddard Space)

No doubt, with North Korea testing nuclear weapons and their delivery systems, the latest surge in questions are a reaction to this behavior. Moreover, North Korea’s state news agency has been explicit about their intention to deploy and detonate an EMP weapon over the United States.

I’ve never been as concerned about man-made EMPs…well, until recently. Rather, I’ve been more concerned about the EMP potential of our local star––the Sun.

Whennot if, we receive a strong EMP from a solar storm like that generated in 1859, known as the Carrington Event–our electronic infrastructure could very well be severely crippled, perhaps even for the better part of a decade.

Concerning, isn’t it?

Let’s come back down to Earth…

As the Wikipedia article indicates, there’s a lot of confusing and misleading information out there regarding EMPs.  And while some of this reportage underplays the seriousness of this very real, if rare, concern, a great deal of it, including the fiction about it, is more alarming than it needs to be.

So I turned to a good friend who happens to be an expert on EMPs.

My pal has worked for thirty-five years designing military radar equipment, broadcast transmitters, and automotive electronics.

His profession requires that he knows how to “harden” equipment against all types of EMP threats, and thus is regarded as a specialist in this field. Because of his professional ties he’s asked that I withhold his name.

My EMP expert friend is also very pragmatic. That’s why I asked him to explain how EMPs might affect us both generally and specifically, in terms of communications and the radio world.

I asked him to address what effects an EMP might have, both nuclear and solar originated, and how what practical preventative measures we might take to mitigate the damage to our radio equipment. His reply follows…


Anxiety over EMP seems to recur every time there is a change in the established order. The premise of Mutually Assured Destruction that has kept us ‘safe’ in the nuclear age vanishes when confronted by a suicidal adversary. That _seems_ to be the case at present.

So let’s look at the facts available:

A nuclear EMP has its peak energy in the 1 MHz range, with appreciable energy even in the 1 GHz range. It has field strengths of up to 50 kV/m.

The wiring inside of modern consumer electronics, including PCB traces, is close to GHz wavelengths, so they will be effective [in] receiving that energy and carrying it to any electronics [to which] it is connected.

There was a series of articles in QST 30 years ago by Dennis Bodson (W4PWF) that should be the go-to reference:

[Note: the following links require that you’re logged into the ARRL website and are a current member.]

The author related results of a number of tests on equipment by the US in EMP simulators.

The impact on vehicles

One observation was that vehicles were not affected.

As a former automotive engineer, I can attest to the lengths to which designers go to make automotive electronics resistant to damage. A vehicle must be designed to withstand operation with no battery, reverse battery voltage, inductive surges, and other abuse. Automotive electronics are designed to operate under radio and TV transmitters without damage.

There are of course anecdotal accounts of ham equipment causing vehicle computers to go haywire, but if (and that is a BIG IF) the equipment was designed properly, there will not be damage. One area where EMP will cause damage in a vehicle is the car radio. It is tied to an antenna that will conduct the surge directly into the very fragile receiver circuitry.

That said, the amount of electronics in a vehicle is hugely increased since these articles were written in 1986, and even after I left the automotive industry in 2006.

The specs for automotive EMI resistance have not changed in that time, though.

EMP hardening

The way that you keep EMP out of any object is to surround it in conductive metal, so that no gaps exist. Think of a microwave oven that must keep the radiation _in_. The screen in the door window has tiny holes you can see through, but much smaller than the wavelength of the oven. Where microwave leaks are most likely to occur is around the door, where the metal shield is not continuous.

If you want to shield electronics from EMP, the coverage by the metal shield must be continuous. A gap or slit will permit the energy to penetrate.

Sample of reclosable ESD bags.

In the silvered plastic Electrostatic discharge (ESD) bags that are very popular for EMP protection, the zip-lock seam is the weak point in the shielding. You can very easily just use two bags, one inside the other, with the seams in opposite directions, to make a greatly improved shield.

Aluminum foil is a great shielding medium, [and] it’s cheap and plentiful.

Use a big piece, and wrap several overlapping layers. It’s hard to do better.

Many of the solutions used for EMI and RFI lose their effectiveness in the high field strengths of an EMP.

The ferrite snap-on chokes saturate at high magnetic field intensities, and lose their permeability, and the ability to stand off conducted surges.

Use of ammo boxes or file cabinets for EMP protection [a popular method promoted by many on the Internet] is of limited effectiveness because of the large gaps between sheets of metal, and the poor conductivity of steel.

A galvanized trash can is a better solution, because of the conductivity of the zinc galvanization.

The gap around the lid should be covered with adhesive copper tape, available at craft and garden supply stores.

Batteries

Batteries are not affected by EMP. But a battery pack with a built in smart charger may be.

Be aware that LiFePo batteries tend to have built-in smart charge controllers.

Store battery packs safely shielded also––but make sure the terminals cannot contact the metallic shield and cause a short!

Tube/Valve radio equipment

Vintage tube radios will likely survive an EMP, but how do you power them without mains electricity? By modern standards, valve gear is power hungry!

Vacuum tube equipment is very resistant to EMP, as [it] can withstand arcing and surges with no damage.

The bigger question is, how do you power it afterward?

Suppress Surges and Unplug

Much of the damage from an EMP will be conducted, coming in on power lines. Always unplug any critical electronics when not in use. Also, put a surge suppressor on every outlet [into which] you have electronics plugged.

It is cheap insurance. Even of you are not in line-of-sight of an EMP, the conducted surge can wipe out costly appliances. I do this as protection anyway because of my ham antenna. When lightning hit the tree outside my house ten years ago, we only lost two CFL bulbs, while every neighbor on our block lost TVs, microwaves, and washing machines.

Gamma Ray Bursts

EMP radiation should be distinguished from ionizing nuclear radiation. Exposure to a gamma ray burst from near proximity to a nuclear event will disrupt electronics also, but that is an entirely separate topic.

Most Important Communication Medium During Disasters

Photo by Tania Malréchauffé on Unsplash

(Hopping on soap box) The most important form of communication is that which covers the shortest distance. Get to know your neighbors. When bad things happen, they will be the people who will help you out, and be the most grateful when you help them. We’re seeing this happen on a massive scale in Houston [Florida and Puerto Rico] right now. (off soap box).

My Disclaimer

The subject of EMP is very controversial. There is a tremendous amount of misinformation out there. There is disagreement even among the experts.

The problem is that since aboveground nuclear testing…ended a generation ago, there is very little relevant information existing, since semiconductor electronics were in their infancy at that time this occurred. Most information that there is has come from EMP simulators, which are assumed to create waveforms close to that of a nuke. We all know…how risky assumptions can be!

But we do know how to make shielding, and we do know what kind of effects will damage electronics, and we can use this knowledge to try to assure that the preparations we make will be sufficient to protect our electronics.

All of these are very hostile EMI/EMC environments, and the specifications for their design are very strict. These designs offer guidance as to how to create EMP resistant electronics. What are offered are opinions, but hopefully well informed opinions. If I’m wrong, I won’t argue about it, there is more at stake than ego.


Answering common questions

Many thanks for these useful insights and explanations. And now, with all of this in mind, let’s re-evaluate questions about EMPs and radios:

“I understand tube/valve radios can survive an EMP. Which model should I buy?”

My answer: You’re correct; as discussed above, vacuum tube equipment is very resistant to EMP, as it can withstand arcing and surges with no damage.

However…without mains power (the most likely result from a strategic EMP) how will you power tube gear––? Many tube radios were never designed to be operated from a battery source. Those that could, require batteries with a fairly exceptional amount of capacity. Vacuum tube radios are not efficient compared with modern solid-state battery-powered radios.

If you have an generator or power source that is hardened to survive an EMP, and you have a plentiful supply of fuel to run it, then you may consider a tube radio. Otherwise––or better yet, additionally––protect a much more efficient portable radio.

“What radio can survive an EMP?”

Any radio that is properly shielded from the effects of EMP should survive an EMP.

“How can I protect a radio or other portable electronics from an EMP?”

After you’ve chosen which radio to protect, take the extra precaution of removing any attached telescopic antenna. Most antennas are held in place with a simple tiny stainless steel screw/bolt. Unscrew it, pull the antenna off, place both pieces in a small bag and keep it with the radio.

Next, place the radio in a container that will act as a “Faraday cage” to exclude an EMP’s electrostatic and electromagnetic influences. There are a number of commercial products specifically designed for this use, but it’s more simple and affordable to adopt one of the procedures our expert outlines above.  Let’s re-cap:

ESD Bags

Find a bag that’s large enough to fit your radio; many of the bags designed for SATA hard drives should fit more compact radio models.

Place the radio (and its detached antenna) into the ESD bag and close the zip seam.

Then, place the ESD bag containing your radio equipment into another ESD bag, making sure the bag seams are on opposite ends.

Aluminum Foil

 

Consider wrapping your radio or electronic device in its box. Not only does it insulate the contents, but it makes an easier surface to wrap in foil.

Wrap the radio in at least three layers of aluminum foil. Make sure all seams are tightly sealed with each layer of foil. Each layer should completely enclose and protect the radio.

I wrapped this radio in three layers of foil, carefully sealing seams on each layer.

Galvanized Trash Can

As mentioned above, items can be placed in a galvanized trash can for protections.

Simply line the inside of the can with a dielectric material (cardboard, thick cloth, foam, or something similar) so the contents cannot touch the sides, bottom, or lid of the can.

It may be overkill, but I might also wrap my electronics in aluminum foil before placing it inside, again making absolutely certain your equipment in its foil wrap is NOT touching the metal of the can.  This would simply serve as a secondary–redundant–layer of protection.

If you live in a humid area, you might put some sort of moisture protection inside as well.

On to Part 2…

In the final part of our primer, we’ll take a look at what sort of radios you should consider packing away for emergency use, discussing selection criteria.

I’ll link to this article in the coming weeks, too, once it’s published, so stay tuned for more on this intriguing subject. Follow the tag: EMP

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