On this page are links to additional on-site and off-site references providing some theory, practical, and data results from a variety of electrical, broadcast and commercial radio experts.
EACH piece of equipment should be connected by a single discrete unique conductor to THE SINGLE RF/STATION ground point. NOT daisy-chained or looped between chassis/shield to other equipment. HOME RUNS folks!
There is NO expectation that THE ground point is capable of or meant to dissipate or absorb a lightning strike.
THE ground point and grounding equipment is intended to and can provide a SINGLE POINT to sink voltage differences between chassis, eliminate the differences of inter-chassis potentials and coupling, inhibit re-radiation of stray currents to other devices, and help keep AC/DC/RF currents off the AC-mains conductors and safety ground.
Did you know typical earth ground resistance is above 200 ohms? That is most certainly NOT the zero-ohm impedance needed for proper radials/counterpoise for verticals.
The first three links below provide considerable text and helpful graphics. Each article contains essentially the same/similar information which also corresponds to some degree with what is in-practice, recommended and even necessary in "RF shops" from small to large broadcast and two-way installations.
Unfortunately the National Electrical Code, NFPA and other U.S. standards bodies do not have a spec or code requirement for RF installations, as RF is still fairly specialized and isolated (as it should be) from A.C.-mains power concerns.
The common thread through all of these is:
* the goal is to ensure any and all external/stray (not intentional as-in coax or twin-lead) RF is routed as directly as possible to EARTH. Not some long meandering inadequate 14 gauge electrical wire, or conduit looped through a power box.
* Power mains safety ground is NOT a good RF ground
* Your RF system should have its own stout, brute force, highly effective EARTH GROUND
* Each individual piece of RF station equipment, from power supplies to rotor control to antenna switch to receiver, transmitter and amplifier, tower(s) and antenna(s)/feedline should have their own individual dedicated ground wire running directly to the single unique RF ground rod/bus.
* The National Electrical Code, and where adopted, requires exterior antennas and structures to be grounded.
A few pictures of lightning damage.
How lightning protection systems work
NOT incompatible with required station/utility ground systems... so integrate.
Video about lightning protection systems
When he mentions ground rods... refer to Mike Holt's video below, and bond all of them together...
W. Reeve Article on NEC Implementation for Amateur Radio (local copy)
Kuhlman's SeaPac Presentation on NEC and Amateur Radio (local copy)
Mike Holt's Video Collection
The Grounding... videos, especially resistance testing (below), are very telling!
Mike Holt's Ground Resistance Testing
Soil and Lightning
No1PC: Station Grounding Diagrams
W8JI - Station Grounding
N7DY - Station GroundingMIL-STD-188-124B
KF6GDJ - Station Grounding
Commercial Telecom Paper
A very good paper on soil resistance - must read.
Motorola R56 at Repeater-Builder
Polyphaser - Solutions for Comm Sites
Grounding versus Counterpoise
NO1PC As-Built Single-Point Station Ground
© 2015 de Jim Aspinwall, No1PC
Rights of referenced and linked material up to their respective authors/publishers/owners.