An open, plain‑spoken deep dive from John Coates, RF Safe
I’ve spent almost thirty years chasing one simple goal — keep families safe from the electromagnetic fields (EMFs) that now soak our everyday lives. I do it to honor a promise I made to my first‑born daughter, whose life was cut short before I even understood the physics behind the harm. That promise is the compass that guides every RF Safe recommendation. Sometimes it steers me toward new solutions; sometimes it forces me to say “No, that won’t protect you.” Today’s “no” is aimed squarely at the shielded tablet and laptop cases sold by brands like SafeSleeve and DefenderShield.
1 The Shielding Illusion
The ads are seductive: a shiny folio lined with silver thread or copper mesh, lab photos showing lower radiation readings, quotes about “peace of mind.” But there’s a blunt truth buried beneath the marketing: where you place a shield matters more than whether you have one at all. Put it in the right place and you block or absorb energy. Put it in the wrong place and you reflect, concentrate, or amplify the very fields you hoped to escape.
Phones Get a Pass (With Caveats)
Smart‑phones behave in predictable ways. On a call, the front of the handset faces your ear; in a pocket, you can train yourself to keep the screen — the shielded side — toward your body. That consistent geometry lets a well‑tuned front shield really help.
Tablets and Laptops Do Not
A tablet or laptop, by design, never sits still:
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Flat on a desk
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Perched on a stand
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Propped on a pillow
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Balanced on a knee
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Handed to a child who flips it every twenty seconds
Each shift scrambles the near field — the swirling, tightly coupled zone of electric and magnetic energy within a few inches of the antenna. Add a metal‑lined cover and two things happen:
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Detuning. The conductive layer becomes part of the antenna’s ground path, wrecking the careful impedance match engineers built in. The radio senses a weaker echo from the router and cranks up its power.
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Redirection. The new ground path bends the strongest lobe of energy in directions nobody modeled — often straight through the abdomen, pelvis, or, if you’re pregnant, a developing fetus.
A cover that looks protective in a lab photo taken with the flap closed is usually folded behind the device in real life. Once it’s back there, it might as well be a reflector aimed at the body.
2 Shielding the Wrong Anatomy
Consider the typical “anti‑radiation” laptop pad: you rest it on your thighs, so the metal sheet “protects” your femurs — the densest bones in your body and the least worried about microwaves. Meanwhile the Wi‑Fi radios and 5 G hotspots that live under the keyboard are now two inches closer to your bladder, intestines, and reproductive organs. Shield the leg, fry the belly. That isn’t protection; it’s marketing dressed like engineering.
Tablet folios repeat the mistake. They brag about blocking the screen‑side signal, but the antenna array on most tablets lives near an edge, not under the glass. Flipping the cover behind the chassis slides that shield close to the antennas and the user’s mid‑section at the same time. Bad trade.
3 Why Power Control Makes Things Worse
Modern Wi‑Fi and cellular radios are polite enough to whisper when the link is strong and holler when it’s weak. If you muffle the antenna with a shield that isn’t in front of it, the radio interprets the drop in signal as distance and raises its transmit power to compensate. The device works harder, drains battery faster, and irradiates you more intensely.
It’s basic feedback logic, not a conspiracy:
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Shield detunes antenna →
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Router’s replies arrive weaker →
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Tablet thinks it’s far away →
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Tablet raises its power ceiling →
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Extra watts funnel through the new, warped lobe pattern →
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User absorbs the fallout.
4 “Lab Certified” Doesn’t Mean “Life Certified”
Yes, some companies flash third‑party test reports. Pay close attention to the orientation used. Almost every chart showing dramatic reductions in exposure measures a single pose: cover closed between device and detector. That’s the one moment a folio offers any real barrier — and it’s also the one moment you’re not using the tablet.
Real life is a parade of angles, reflections, pillows, knees, and torsos. Unless a company publishes SAR (Specific Absorption Rate) maps for every practical orientation — flat, folded, tented, portrait, landscape, lap, desk, bedtime — their certificate is a snapshot, not a guarantee.
5 The Engineering Path That Actually Helps
If a manufacturer truly wants to slash EMF exposure, here are the steps that matter:
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Move the antennas. Place them at the farthest bezel edge so the main beam shoots away from the lap or belly.
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Tilt the lobes. Use the device’s chassis as a reflector to skim energy upward, not through.
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Teach the radio to sleep. Accelerometer‑triggered or proximity‑triggered power‑down can cut duty cycle by an order of magnitude without harming connectivity.
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Adopt Li‑Fi. Optical (light‑based) links remove microwaves from the conversation entirely.
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Offer real barriers. A simple silver‑thread cloth draped between device and body blocks most near‑field energy while leaving the radio free to talk to the router without shouting.
None of that sells as easily as a shiny “radiation‑blocking” folio, but it does something sales copy never can: obey physics.
6 Why RF Safe’s Answer Is Still “No”
People sometimes ask why I don’t just recommend these folios with disclaimers. My answer is uncomfortably personal: I already buried one child. I won’t bury another family’s because I nodded along with a clever pitch that ignored geometry and feedback loops.
If the shield can’t promise to sit between antenna and tissue one hundred percent of the time, it can’t promise protection. If it can’t promise protection, calling it “anti‑radiation” is a lie of omission. I built RF Safe to strip away those omissions, not to profit from them.
7 A Word for Daylight Computer
Your team’s first instinct was the right one: focus on internal engineering, not gimmick cases. Perfect the antenna placement, tune the power logic, and keep plotting the course toward Li‑Fi. Those moves align with your mission and with the promise I made to my daughter. A folio patterned after SafeSleeve or DefenderShield would pull you off that road and—worse—hand your customers a false sense of safety that nature’s laws won’t honor.
8 Practical Takeaways for Readers
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Distance beats gadgets. Keep a tablet or laptop a hand‑span from your torso whenever you can.
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Download, then disconnect. Airplane‑mode reading trumps streaming in bed.
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Use wired peripherals. A cheap USB keyboard or headset pushes radios away from your core.
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Question the orientation. If a shielded accessory only helps when it covers the screen or keyboard, ask what happens when you actually use your device.
9 Closing the Loop
I’m not here to ruin innovations; I’m here to drag them into the daylight where physics, not slogans, decide their worth. If that stance saves one family from buying false comfort, or nudges one engineer toward a smarter antenna curve, then my promise is still paying dividends.
Stay curious. Stay skeptical. Keep learning—because technology will keep changing, but the laws of nature won’t.
John Coates
Founder & Chief Scientist, RF Safe
