07/02/2026
EMP AND FARADAY AWARENESS!
There are many videos on YouTube about EMP protection only a few mention the principles and what matters.
An EMP is a brief surge of electromagnetic energy that can occur as a radiated electric or magnetic field or as a conducted electric current, depending on its source. Its short duration spreads the energy over a wide range of frequencies, making it capable of affecting multiple types of electronic systems simultaneously.
So what is a Faraday Cage?
A Faraday cage is just a conductive “shield” that keeps outside electric signals from getting inside by making the outside surface carry all the electrical charge.
What is Attenuation ?
Attenuation refers to the reduction in the strength (amplitude or energy) of an electromagnetic signal as it passes through a material, device, or system. In shielding and filtering contexts, it measures how much the unwanted interference is weakened before it reaches the sensitive equipment.
Next let's look at the physics of an EM Pulse.
EMPs typically spans from very low frequencies (VLF 3 kHz) to extremely high frequencies (EHF 50 dB attenuation is a standard baseline for Electromagnetic Pulse (EMP) Shielding Mitigations because it safely reduces intense electromagnetic fields to harmless levels. This level of protection prevents destructive voltage spikes from damaging sensitive electronic components.
What 50 dB Means
Decibels (dB) measure logarithmic power ratios. A 50 dB attenuation means the electromagnetic field entering a shielded enclosure is reduced by a factor of 10⁵ (100,000 times) in power, or by roughly 316 times in voltage. In percentage terms, this blocks about 99.997% of the EMP energy.
How EMP Shielding Works
EMP shielding is about protecting electronics from these damaging voltage spikes. The most common method is the Faraday cage by enclosing sensitive devices in a conductive material (like metal) that redirects the EMP energy around the protected space instead of letting it enter.
When an EMP hits:
The conductive shield absorbs or reflects the electromagnetic wave.
Any excess energy is diverted away from the electronics, often to the ground.
Inside, the electronics remain unaffected because there’s no strong induced current.
Why it’s needed
Without shielding, the fast-changing electric field of an EMP induces dangerous currents in wires, circuit boards, and antennas, frying sensitive components. This is especially dangerous for the E1 pulse from a nuclear EMP, which can arrive in less than 25 nanoseconds; that's too fast for most surge protectors.
Simple Analogy
Think of EMP shielding like sun screen on steroids: the EMP energy “hits” the shield (sun screen), and instead of going through, it’s redirected or absorbed, so the electronics inside are safe.
In short: EMP shielding is a way to block or redirect electromagnetic energy before it can damage electronics, using conductive enclosures or fast-acting protection devices.
Why some cell phone are blocked and others are not
Cell phones use frequencies in these bands.
• 4G (LTE): Expanded to 700 MHz, 1700 MHz (AWS), 1800 MHz, 1900 MHz, 2300 MHz, 2500 MHz, and other mid-band frequencies to balance coverage and capacity.
• 5G: Uses sub-6 GHz bands (similar to 4G) and millimeter-wave (mm Wave) bands above 24 GHz, providing ultra-high-speed data but with shorter range.
Microwave Oven Fail
A microwave oven is engineered to keep one specific frequency 2.45 GHz inside the box, the resonant frequency cooks your leftovers. The mesh in the door has holes precisely calibrated to that wavelength (2.45GHz). The holes in that mesh are roughly 1 millimeter in diameter; microwaves used for cooking have a wavelength of about 120 millimeters. Since the waves are roughly 120 times larger than the holes, they can’t escape. The theory is the same mesh would block incoming EMP energy. Wrong it’s a single-frequency filter, not a broad-spectrum shield.
Cell phones operate across multiple bands from around 700 MHz up past 2.5 GHz. AM radio sits down in the 530-1700 kHz range; while an EMP hits across an enormous frequency spectrum simultaneously.
So how can I protect my stuff
Testing has proven the Dri-Shield moisture barrier bag 3400 series bags have true EMI Attenuation of 45 dB when tested 1 to 10 GHz. They are also puncture resistance to 20 lbs
These bags were developed by 3m who sold off their static bag line to Desco Industries. Desco now sells them under its SCS (Static Control Solutions) division.
Your bag must be at least IEEE 299 2006 certified to be effective. IEEE 299-2006 is a standard for measuring the effectiveness of electromagnetic shielding enclosures across a wide frequency range.
The standard defines tests to measure shielding effectiveness over a frequency range from 9 kHz to 18 GHz, with possible extensions from 5 Hz up to 100 GHz.
The other option is MIL-STD-188-125. This standard addresses minimum testing requirements for demonstrating that prescribed performance criteria have been achieved and for verifying that the installed H**P protection subsystem provides the operationally required hardness for the completed facility.
