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Grounding for Amateur Radio

Grounding for Amateur Radio. Harold C. Fleischer, III AE5AS. Ohm’s Law. V = I x R Voltage = Current x Resistance. Ohm’s Law. V = I x R Voltage = Current x Resistance V = I x Z Voltage = Current x Impedance. Ohm’s Law. V = I x R Voltage = Current x Resistance V = I x Z

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Grounding for Amateur Radio

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  1. GroundingforAmateur Radio Harold C. Fleischer, III AE5AS

  2. Ohm’s Law V = I x R Voltage = Current x Resistance Grounding For Amateur Radio

  3. Ohm’s Law V = I x R Voltage = Current x Resistance V = I x Z Voltage = Current x Impedance Grounding For Amateur Radio

  4. Ohm’s Law V = I x R Voltage = Current x Resistance V = I x Z Voltage = Current x Impedance V = ((1/C) ∫idt ) + (i x R) + ( L x (di/dt) ) Voltage = Capacitance divided into the integral of Current over time + Current times Resistance + Inductance times the derivative of Current over time This equation is why imaginary numbers and polar coordinate mathematics appear in the license examination for Amateur Extra. Grounding For Amateur Radio

  5. Battery and Voltage + No Impedance Voltage Battery No Current - Grounding For Amateur Radio

  6. Basic Complete Circuit + Impedance Voltage Battery - Current Exists Grounding For Amateur Radio

  7. Short Circuit + No Impedance Voltage Battery - Current  Infinite Grounding For Amateur Radio

  8. Open Circuit + No Impedance Voltage Battery - No Current Grounding For Amateur Radio

  9. Basic Capacitance Circuit + Capacitance Voltage Battery - DC – No Current Grounding For Amateur Radio

  10. Basic Capacitance Circuit + Capacitance Voltage Battery - DC – No Current Can Current jump the gap in a capacitor? Grounding For Amateur Radio

  11. Basic Capacitance Circuit + Capacitance Voltage Battery - DC – No Current Can Current jump the gap in a capacitor? Yes, capacitors have a breakdown voltage. Grounding For Amateur Radio

  12. Can Electrons Jump Air Gaps? + Voltage Battery Spark Plug - Current Yes, spark plugs in a car, etc., are all about jumping an air gap to create a spark. Grounding For Amateur Radio

  13. Lightning Jumps Air Gaps + When Voltage from static electricity gets high enough, electrons will jump the gap and produce thunder and lightning Voltage Currents will be brief, but very high. Ground - Grounding For Amateur Radio

  14. Electrons Always Wantto go to Ground + Voltage Radio Transceiver + Voltage Ground - - Grounding For Amateur Radio

  15. Basic Ground Problem Vm + Impedance Voltage Battery - Vc0 Current Exists If Vc0 does not equal Vg, Electrons want to get to ground. Vg Ground - Grounding For Amateur Radio

  16. Basic Electrocution Problem Vm + Impedance Voltage Battery - Vc0 Current Exists Vg Ground - Grounding For Amateur Radio

  17. Basic Grounding Solution Vm + Impedance Voltage Battery - Vc0 Current Exists Vc0 = Vg, and you are no longer the best path to ground. Grounding Wire Vg Ground - Grounding For Amateur Radio

  18. Basic Grounding Truth • Grounding is like Pregnancy • You are Grounded or you are not Grounded. • There is no such thing as partially Grounded. • Ideally, you have a Ground when the ground resistance value is 0 ohms. • NEC requires a ground resistance value of <25 ohms. • NEC recommends a ground resistance value of 5 ohms or less for sensitive equipment. • Type of soil affects what you have to do to get a good ground resistance value. Grounding For Amateur Radio

  19. Ground Resistance Measurements • Very complicated; not necessarily inexpensive. • Must drive ground rod and then other rods to do measurements. • Meters can cost upwards of $200-$300. • The default is to follow the NEC. • Install ground rods or ground plates. Grounding For Amateur Radio

  20. Grounding Rods and Plates • Grounding Rod must be: • Copper or copper clad aluminum. • At least 8’ long with only 3” showing. • At no more than an angle of 45 degrees when driven in. • Measuring Ground Resistance is complicated. • Mechanical Clamp of AWG 6 copper wire or braid. (A high current will melt solder.) • Grounding Rod may be placed horizontal in a 30” deep trench if they can not be installed vertically. • Grounding Plate must be: • 2 feet square ( 1’ x 1’ x 2 sides). • ¼” thick if ferrous, 1/16” thick if non-ferrous. • Hole in center for bolt, nut, and lock washer. • Top of plate must be 5’ below the surface of the ground. (The more square feet in the plate, the more likely Ground Resistance measurement objectives will be met.) Grounding For Amateur Radio

  21. Grounding in a House Panel Meter Grounding Wire Grounding Rod Black – Hot White – Neutral Green - Ground Grounding For Amateur Radio

  22. Example of a House Ground Grounding wire in protective cover Grounding For Amateur Radio

  23. Bonding • Bonding is Grounding • Bonding is tying equipment together to eliminate or dampen inter component electrical interaction: Noise Grounding For Amateur Radio

  24. Number of Groundsfor your Property ONE Grounding For Amateur Radio

  25. Multiple Grounding Rods- One Ground • Shortest Path matters • Ground from Meter/Panel goes straight down to Grounding Rod • Ground from Antenna needs to go straight down even if antenna feed cable has to make a turn to the “Radio Shack • Ground from “Radio Shack” needs to go straight down • Ground from Tower needs to go straight down • Tie all ground rounds together with AWG 3/0 buried 18” deep. Grounding For Amateur Radio

  26. Grounding Example Grounding For Amateur Radio

  27. Grounding Example Example of Lightning Arrestor (Surge Protector) at bottom of drip loop. Grounding For Amateur Radio

  28. Grounding Example Site Plan House HF Antenna Grounding Rod Patio VHF/UHF Antenna Grounding Rod 18” Trench with Grounding Cable Remember: Number of Grounds on Your Property? ONE Grounding For Amateur Radio

  29. Grounding with Tower Example House (with no antennas mounted on it) Grounding Rod (Electrical Service) Patio Grounding Rod (Radio Shack bonding) 18” Trenches with Grounding Cable Remember: Number of Grounds on Your Property? ONE Tower Bonded to Antenna, Each Leg with Grounding Rod, Leg Grounding Rods 6’ apart, & Leg Grounding Rods joined by Ground Wire 1’ deep 6’ Grounding For Amateur Radio

  30. Emergency Generators OSHA Fact Sheet • Frame of portable generator may serve as ground if: • Generator supplies only equipment mounted on it or cord connected equipment through receptacles mounted on it. • Non-current metal parts of equipment are bonded to the frame and grounding conductor terminals are grounded to the frame. • Do not connect a generator to a structure except through a transfer switch. Very sensitive situation that may require generator to be grounded. Grounding For Amateur Radio

  31. Review You ground to: • Protect against an electrical fault • Protect against lightning • Suppress noise in electrical equipment Grounding For Amateur Radio

  32. References • ARRL Handbook, Chapter 28.1, 91st Edition, 2014. • Silver, H. Ward, N0AX, Grounding and Bonding for the Radio Amateur, ARRL, 2017. • Morgan, Jennifer, and Chusid, Michael, Lightning Protection for the Amateur Radio Operator’s Home, QST, ARRL, June 2017. • CECOM TR-96-2, Earth Grounding Pamphlet, May 1996. • OHSA Fact Sheet: Grounding Requirements for Portable Generators, DSTM 10/2005. Grounding For Amateur Radio

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