The word “grounding” — meaning a connection to the Earth — is casually applied to so many different purposes in Amateur Radio, it’s no wonder there are many opinions and misconceptions about it. “Bonding” is a less familiar term to most amateurs. In the electrical sense, bonding simply means “to connect together” so that voltage differences between pieces of equipment are minimized.
Why Are Grounding and Bonding Important?
There are three needs we are trying to satisfy:
• AC safety: protect against shock hazards from ac-powered equipment by providing a safe path for current when a fault occurs in wiring or insulation.
• Lightning protection: keep all equipment at the same voltage during transients and surges from lightning and dissipate the lightning’s charge in the Earth, routing it away from equipment.
• RF management: prevent unwanted RF currents and voltages from disrupting the normal functions of equipment (also known as RF interference or RFI).
Why Is “Grounding” So Complicated?
The very word — grounding — means a lot of different things depending on who you’re talking to and what you’re talking about. Isn’t grounding just connecting equipment to the Earth? That is certainly one definition of grounding.
The British use the terms “earthing” and “protective earth conductor” which are more exact references to what the connection is for. But the layer of soil and rock at the Earth’s surface is not a magic zero-voltage point into which we can pour any amount of electric charge where it safely disappears! The current’s strength and frequency, soil characteristics, whether it is wet or dry, the length of the path to the Earth connection and through the soil — all of these affect what our equipment experiences at the “ground” connection.
Station Grounding for Amateur Radio – Ask Dave