What it is, what it does, how to protect your station Rick Blasco, NX6R

NX6R What is EMP? ElectroMagnetic Pulse caused by:ElectroMagnetic Pulse caused by: –Lightning –Geomagnetic storm –Power line transient –Thermonuclear detonation –E-bomb

NX6R What is EMP? ElectroMagnetic Pulse caused by:ElectroMagnetic Pulse caused by: –Lightning –Geomagnetic storm –Power line transient –Thermonuclear detonation –E-bomb

Lightning NX6R

Lightning Weak “tracer” pulse cloud to ground, followed by strong “return” pulses ground to cloudWeak “tracer” pulse cloud to ground, followed by strong “return” pulses ground to cloud 3-4 pulses or “strokes” per “flash” or “strike”3-4 pulses or “strokes” per “flash” or “strike” Peak current 3 kA to 175 kA (18 kA typ)Peak current 3 kA to 175 kA (18 kA typ) Spectrum falls off more rapidly than thermonuclear crossover 1-10 MHzSpectrum falls off more rapidly than thermonuclear crossover 1-10 MHz NX6R Dennis Bodson [3] and Ron Block KB2UYT [4] and in QST

NX6R Thunderstorm days per year Ron Block KB2UYT in QST [4]

NX6R Strikes per year vs. tower height Ron Block KB2UYT in QST [4]

Thermonuclear NX6R

Thermonuclear Compton effect: gamma rays interact with atmosphere to produce EMPCompton effect: gamma rays interact with atmosphere to produce EMP Can cover large geographic areaCan cover large geographic area Less likely to occur than other sourcesLess likely to occur than other sources EMP probably “least of your worries”EMP probably “least of your worries” Three “strokes” of EMPThree “strokes” of EMP NX6R Dennis Bodson W4PWF in QST [3]

E1 and E2 pulse propagation NX6R Dr. John Foster, et al EMP Threat Assessment Report [5]

E3 pulse propagation NX6R Dr. John Foster, et al EMP Threat Assessment Report [5]

EMP propagation vs altitude NX6R Dennis Bodson W4PWF in QST [3]

NX6R E-bomb "Gort! Klaatu barada nikto!"

NX6R E-bomb Carlo Kopp in Air & Space Power Journal [1] Localized EMP effectLocalized EMP effect Cheap to make ($1000-$2000)Cheap to make ($1000-$2000) Commonly available materialsCommonly available materials Well-known technology (since 1940s)Well-known technology (since 1940s) Multiple delivery methodsMultiple delivery methods Peak current of large device stronger than lightning strokePeak current of large device stronger than lightning stroke

NX6R “Ideal” terrorist weapon Highly disruptive if properly placedHighly disruptive if properly placed Minimum “collateral” damageMinimum “collateral” damage Cheap to makeCheap to make Commonly available materials no need to smuggle into countryCommonly available materials no need to smuggle into country Conventional C-4 plastic explosive impossible to detect from a distanceConventional C-4 plastic explosive impossible to detect from a distance Can be fitted in a van and driven to target siteCan be fitted in a van and driven to target site

NX6R Coaxial Flux Compression Generator (FCG) Carlo Kopp in Air & Space Power Journal [1]

NX6R Virtual Cathode Oscillator (VIRCATOR) Carlo Kopp in Air & Space Power Journal [1]

NX6R Characteristics of an EMP pulse Extremely high energyExtremely high energy Very short durationVery short duration → Energy in RF spectrum

Pulse shapes Carlo Kopp in Air & Space Power Journal 1996 [1]

NX6R Approximate Spectrum of EMP Dennis Bodson W4PWF in QST [3]

NX6R What it does Presents high voltage and high current to:Presents high voltage and high current to: –Antennas –Transmission lines –Rotor cables –Power cables –Microphone and other external cables –Internal equipment wiring –PC board traces –Semiconductor junctions (diodes, transistors, ICs) –Vacuum tubes –Passive components (capacitors, resistors, inductors, etc.)

NX6R Will it move?

NX6R Will all this stuff work?

NX6R Will you have acce$$? “We should have left it buried in the backyard.”

NX6R If it can arc, smoke, or melt … IT CAN FRY! IT CAN FRY!

NX6R How it does it ConductionConduction –Antenna system –Power lines –Ground connection InductionInduction –Cables and wires act as antennas –Coils, chokes, and transformers act as voltage generators

Larry Scheff W4QEJ in February 2008 QST [2]

NX6R Ohm’s Law (DC) E RI P IE

NX6R Ohm’s Law (RF - simplified) I rf V rf 2πfc2πfc I rf 2πfL2πfL 2π =

NX6R Ohm’s Law (RF - simplified) P rf c LI rf 2 V rf 2 22

NX6R Protection (hardening) techniques Disconnect external cablesDisconnect external cables “Stout” grounding“Stout” grounding Transient suppressorsTransient suppressors Energy-tolerant componentsEnergy-tolerant components Faraday cage / shieldingFaraday cage / shielding Ron Block KB2UYT in QST [4]

NX6R “Stout” Grounding Ron Block KB2UYT in QST [4]

NX6R “Stout” Grounding Common “bulkhead” ground point “single-point ground panel”Common “bulkhead” ground point “single-point ground panel” Suppressors external to building keep the strokes outside!Suppressors external to building keep the strokes outside! Multiple ground rods interconnected with #6 or larger wire per National Electrical CodeMultiple ground rods interconnected with #6 or larger wire per National Electrical Code Ron Block KB2UYT in QST [4]

NX6R Lightning suppressors Ron Block KB2UYT in QST [4]

NX6R Modified Faraday Cage Steel file cabinetSteel file cabinet Add steel plate to close bottomAdd steel plate to close bottom Single connection to groundSingle connection to ground Energy flows around the faraday “shell” to groundEnergy flows around the faraday “shell” to ground Good shielding below 10 MHzGood shielding below 10 MHz Add shielding gaskets around drawers for protection to VHF/UHFAdd shielding gaskets around drawers for protection to VHF/UHF Store spare equipment, microphones, antennas, coax, and cables for use after “attack”Store spare equipment, microphones, antennas, coax, and cables for use after “attack”

NX6R Other measures Reduce inductance of ground connections large diameter wire or copper flashing 1”-3” wideReduce inductance of ground connections large diameter wire or copper flashing 1”-3” wide Multiple length parallel wires to ground rods avoid odd λ/4 multiples throughout spectrumMultiple length parallel wires to ground rods avoid odd λ/4 multiples throughout spectrum Shorten length between power line suppressors and equipmentShorten length between power line suppressors and equipment Coil cables keep ends separatedCoil cables keep ends separated Optical fibreOptical fibre Optical storage (CDs and DVDs)Optical storage (CDs and DVDs)

NX6R Ohm’s Law (RF - simplified) I rf V rf 2πfc2πfc I rf 2πfL2πfL 2π =

NX6R Other measures Reduce inductance of ground connections large diameter wire or copper flashing 1”-3” wideReduce inductance of ground connections large diameter wire or copper flashing 1”-3” wide Multiple length parallel wires to ground rods avoid odd λ/4 multiples throughout spectrumMultiple length parallel wires to ground rods avoid odd λ/4 multiples throughout spectrum Shorten length between power line suppressors and equipmentShorten length between power line suppressors and equipment Coil cables keep ends separatedCoil cables keep ends separated Optical fibreOptical fibre Optical storage (CDs and DVDs)Optical storage (CDs and DVDs)

NX6R References 1.Kopp, Carlo “The Electromagnetic Bomb - a Weapon of Electrical Mass Destruction”, Air & Space Power Journal Scheff, Larry W4QEJ “Lightning: Understand It or Suffer the Consequences” QST Parts 1-2: February, March Bodson, Dennis W4PWF “Electromagnetic Pulse and the Radio Amateur” QST Parts 1-4: August, September, October, November 1986 condensed from “Electromagnetic Pulse/Transient Threat Testing of Protection Devices for Amateur/Military Affiliate Radio System Equipment” National Communication Systems Report NCS TIB Block, Ron KB2UYT “Lightning Protection for the Amateur Station” QST Parts 1-3: June, July, August Foster, Gjelde, Graham, Hermann, Kluepfel, Lawson, Soper, Wood, and Woodard “Report of the Commission to Assess the Threat to the United States from Electromagnetic Pulse (EMP) Attack” 2004, commissioned by Public Law , Title XIV, § Tracy, Mike KC1SX “Lightning Protection” QST Lab Notes Parts 1-2: October, December 1994