EMP-Proof Your Radio Comms With a USGI Ammo Can Inexpensively
How can you EMP-proof select comm gear for under $100? You can do this more easily than you might think. Radio comms are radio-based systems that can communicate across distances from a few miles up to thousands of miles, under the right atmospheric conditions. In order of range (and cost) these radio comms include walkie talkies using the Family Radio Service (FRS) and the General Mobile Radio Service (GMRS). Next, at higher cost and more range, is citizens band radio or CB. At the top end in price and range is Amateur Radio, fondly known as Ham radio. Be aware that all cell-based devices, like cell phones and tablets, are also radio comm systems, but they all rely completely on third parties that are under government regulation to keep the system operational. For that reason we will limit ourselves to direct two-way radio issues only.
The rugged storage capabilities provided by USGI metal ammo cans are obvious. But an amazing non-obvious feature is their ability to act as a shielding enclosure to protect your sensitive comm and other sensitive electronics from an EMP event. Large-scale high energy atmospheric transients can come from a solar coronal mass ejection (CME) striking earth’s atmosphere or a strong electromagnetic pulse (EMP) from a localized EMP device or a nuclear detonation. Regardless the source, the effect is that the same potential for damage exists when power lines or antennas convert these high-energy fields into current flow through the attached wires or other conductors. The result is significant damage to connected circuit components that are unable to withstand the overload. This can all take place in a few milliseconds.
Fortunately, an electrically conductive solid metal box like an ammo can has an inherent property called the Faraday cage effect that can shield its contents from large external transients. Michael Faraday realized in 1836 that an electrostatic electric field would not penetrate a metal enclosure. Later it was determined that same effect prevents penetration from other energy fields such as electric, magnetic or radio frequency. The Faraday cage works because the traveling energy field transforms into an induced voltage and current flow across the surface of the conductor (in this case the metal box) to ground or eventually dissipates into the surrounding area without affecting the contents of our box which is now our Faraday cage. Secondary grounding is not essential. However, make sure no conductor like a power cord or antenna is connected through or penetrates the enclosure or all shielding bets are off. Those penetrating conductors will act as an antenna also and expose the contents to unwanted energy spikes. To clarify your own understanding of EMP and RF shielding I direct you to Don White’s excellent book on the subject.
To implement this idea, put your radio gear or other sensitive electronics inside the box and make sure it is closed tightly. Making sure the top and bottom are electrically connected with an ohm meter is a nice for peace of mind. Ammo cans usually contain a rubber seal between top and bottom but connect electrically through the hinge pins. You may want to attach a small gauge lead as a redundancy between the top and bottom. A decent alternative to an ammo can would be to use a large zip style static shielding bag that is kept tightly closed. The zip close style sized for a 5-gallon bucket would be a good choice. If you use such a bag, then the outside box composition doesn’t matter, because the conductive foil layer inside the bag is the actual Faraday cage.
Plan to purchase some assortment of spare walkies, handheld or mobile Ham set, cell phone, and solar charger and have them properly stowed. I use two deep .50 cal cans to hold four GMRS and FRS walkie-talkies with charger bases ($60 total for both sets), a Cobra CB base, and CB handheld (bought used with antennas for $100), two Baofeng UV5R dual band handheld Ham radios (bought new on Amazon with spare batteries, hands-free mike headsets, upgraded antennas for $125), and a 50W Kenwood TMV71 dual-band Ham radio (like-new for $300 at a Hamfest) with a 15 Amp hr battery (new on Amazon for $30). The Kenwood can also double as a relay repeater that can extend the range of the Baofengs to about 30 miles. The folding solar charger (GoalZero $75) is to keep it all topped off and is rated at 7 watts with outputs of USB 5V and jacks for 12V. Make sure you have all the adapters you need as well. It is snug, but it all fits. The total of what I paid for the gear is shown. Adding the cost of an antenna for the Kenwood, some rechargeable AAs for the handhelds, and the two deep 50 cal cans off Craigslist cost me a total of just under $775. I consider the extra investment in stowed gear some of the least expensive insurance available, because the ability to be back on the air the very “day after” for short range comms at the retreat or over some distances with the Kenwood Ham radio to reach others will be priceless.
Wireless Video Security System Using Smart Phones
Would remote motion-activated images sent to your smart phone for $100 interest you? I thought so. We are now officially a generation of screen junkies. Recent research tells us that the average adult uses their smart phone or tablet to do an average 224 tasks per day, and that doesn’t consider the impact of new apps and features added with each upgrade. I’m not here to debate the culture of mobile screen fixation but to highlight an app that can turn the familiar mobile device, a mixed network of Androids and iPhones, into a sweet motion-activated video surveillance system. It’s not just your smart phone anymore; it becomes your pocket motion-sensitive wireless video security system, and it’s as functional as it is inexpensive.
It started when I got my backup phone. I had reported a roadside emergency via 911 in late 2012 and discovered that law enforcement had locked my cell phone to monitor the audio until they were satisfied things were resolved. This is now standard practice everywhere. The next day I researched and bought a backup smart phone. Specifically, it was an LG Android TracFone purchased on Amazon for $25 with three months service and 600 minutes air time. If I ever have another emergency and call 911, I now have a way to make important calls to my family, lawyer, or other emergency responder if needed. Now I renew annually and get 600 minutes of airtime and 12 months of service for $99. Sometime later, I saw a free motion detector app called Motion Detector Pro from MVA on Google Play. MVA also has a version for the iPhone, but I feel a lot better leaving a $25 Android phone as an unattended camera than I do a $200 iPhone.
Select the correct version for your iPhone or Android 2.2 or higher. Next, download and install the app. Only the device used for surveillance needs the downloaded app. Open the app and choose your options from the settings tab to setup your device as a remote surveillance camera with motion detection functionality. Once the adjustable motion threshold is triggered, it sends an email or a text message with a linked picture to whatever device or email account you specify. It gives you remote video capability to monitor an area of your choosing with your smart phone and get notification if a trigger event occurs. I will leave the possibilities to you.
Once enabled, it will take a picture when the camera sees a movement and send it to an email or another phone. The sensitivity and area for motion detect are user defined. You can remotely start, stop, and reset it by using a password-protected text message. It also indicates real-time on the phone’s display where the movement is detected. There is also a user-enabled stealth mode, which closes the app so the phone looks off as soon as it is touched. You can also store the surveillance images on the cloud or locally on the phone’s SD-card. I have used these features, and they all seem to work on my inexpensive LG phone.
Using this system made it possible for a friend to ride his $800 mountain bike to work and safely park it unattended. The phone points outside his office window with a clear view of the bike. Several times he has been alerted on his daily carry cell phone with an image of someone “looking” at it up close. When he immediately shows up, they either ask questions or move along, but now everyone knows it is being watched, which is very cool. On a final note, the app is ad-supported, but you can make the ads go away for a nominal donation via the app’s settings menu.
Make sure you can power everything off-grid. Keep in mind that you won’t be multiplying much force with the devices described here without some way to power them. Much has been written on Survivalblog about making sure your battery-operated devices and portable communication gear can be recharged in the absence of grid power. Off-grid alternatives can be easily managed in the short term with a generator, as long as fuel is available. My favorite option is solar from a fixed or small portable system. It will of course need to be EMP-proofed. Also, there is thermoelectric power generation, like the BioLite campfire unit. It works, but it is a low power solution. Wind or hydro power are additional ways to keep your stuff charged. Rather than replicate the detail of the choices here, search “off grid power” on SurvivalBlog, and read some of the excellent articles there. I have two linkable Honda 2kW generators, a 1500W portable solar system mounted on a 6 x 14 utility trailer, and several portable folding chargers from 7W to 125W, and lots of Sanyo eneloops. Just remember the old joke: Q. “What do they call a flashlight without batteries?” A. “A hammer.”