Practical Guide for Users / Installers:

• This is a brief summary of Grounding systems.
• Lightning protection and Protectors.
• Practical considerations for materials and installation.

HF (High Frequency 1 to 50 MHz)

• HF radios require an RF (Radio Frequency) ground for proper radiation.
• Poor grounds will give very poor radio range.
• The conductor from the rods (2 or 3)must be #4 wire or 1/4 inch copper tubing.
• Conductor clamped to rod
• Rods are 10 foot long, spaced at 5 to 8 feet apart (2 or 3 rods)
• At the equipment end use a copper bus bar or 3/4" copper tubing
• The equipment is grounded to the bus by #12 solid copper wire.
• Ground all equipment such as filters, power supplies, Transmitters, Receivers.
• Do not assume that Antenna coax leads are a good ground.
• Avoid using stranded wire. It adds RF impedance to the ground system.
• Lightning protectors are put in the antenna coax leads and tied to bus at the building
  entry point.
  
• A good low impedance ground conductor is 1" to 3" wide copper strap of any thickness.
• Grounding will prevent electrocution of individuals operating the radios.
• Coax should turn at a right angle when it leaves the lightning protector.
• Keep the lightning path straight, short and direct to the ground rods.

HF (VHF Frequency 50 to 1000, or more, MHz)

• Grounding has minimal effect on the RF radiation of the system.
• Grounding will prevent electrocution of individuals operating the radios.
• Lightning protectors can be made or purchased because of their sizes.
• Lightning protectors are 1/4 wave (less velocity factor) shorted stubs made from coax cable.
• Rods and cables are the same as HF systems above.
• Ground cables from all antennas to ground rods are #4 or larger wire.
• Tower grounded with a system of rods at base and tied to legs of tower. For example,
  Put three rods in a triangle shape around the tower. Run a #4 wire in a "ring" to the three rods
  and lay it on the ground. From each rod run a wire to each leg of the tower.
  
• For a tower maximum ground system, #4 wire cable is run up tower to top. Antennas grounded
  to this cable as required.
  

Lightning Protectors

• For open wire transmission lines a simple spark gap can be made of metal.
• For coax cables, there are many companies that sell lightning protectors.
• Gas discharge types are common. They have replaceable elements.
• One can build shorted 1/4 wave coax stubs for VHF and UHF frequencies.

I hope this information is of some use to you !!

E-Mail to Al Muir: ve7beu@muircom.com

NOTE: Prices are subject to change without notice.

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