Elmers: RF and Station Ground References

Essential RF and Station Ground / Bonding Data

 

Station Grounding References

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 bonding 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 bonding point and grounding your equipment is intended to and can provide a SINGLE POINT to sink voltage differences between chassis, eliminate the differences of inter-chassis power and RF potentials and coupling, inhibit re-radiation of stray (power and RF) currents to other devices, and help keep AC/DC/RF currents off the AC-mains conductors, and augment 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. Different topic about antenna resonance, currents and function.

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.

Articles from N0AX/Ward Silver, NR2B/Ron Block, and FlexRadio linked-to below all draw us to a common ubiquitous them. They are all specific and consistent, and track with NEC and commercial standards - JUST DO IT RIGHT!

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 Resistance

Soil and Lightning

No1PC: Station Grounding Diagrams

N0AX/Ward Silver's EXCELLENT Coverage of Grounding and Bonding

Part 1 of 3 - NR2B/Ron Block's Coverage of Protection, Grounding and Bonding

Part 2 of 3 - NR2B/Ron Block's Coverage of Protection, Grounding and Bonding

Part 3 of 3 - NR2B/Ron Block's Coverage of Protection, Grounding and Bonding

Grounding Systems in Ham Shack via FlexRadio

W8JI - Station Grounding

N7DY - Station Grounding

MIL-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

 

 

AmateurRadioElmers.org Radio Page

AmateurRadioElmers.org Home Page

© de Jim, No1PC
Rights of referenced and linked material up to their respective authors/publishers/owners.