On 5/3/2012 5:51 AM, Bob McGraw - K4TAX wrote:
The method suggested by Bob McGraw is to have each piece of equipment on the
desk connected to a common point, preferably the station power supply ground
terminal. I use #10 AWG automotive primary wire for this application. Lugs
on each end are crimped and then soldered. One jumper for each piece of
equipment to the common point or ground lug on the station supply.
In addition to being good practice for RFI and lightning, bonding all
equipment together, chassis-to-chassis, greatly reduces issues with hum
and buzz caused by AC leakage currents. These bonds should be short,
fat copper (#10 is a good choice, and I use braid stripped from RG8).
Doing this bonding to a common point rather than chassis-to-chassis is
WORSE from a hum and buzz point of view, and no better from a lightning
protection or RFI point of view. This collection of chassis-to-chassis
bonds is what must be bonded to all other grounds as noted below. A
further reduction in hum and buzz is easily achieved by getting all
power for radio equipment, and all other gear connected to radio
equipment, from the same AC outlet, or from AC outlets that share the
same "Green Wire," or from outlets whose Green Wires are bonded together.
On lightning protection, this should be outside of the house using devices
such as Alpha Delta systems, Polyphaser or arc gaps and these should be
applied to all feedlines and rotor control cables. Be sure the ground
system for the station or tower is bonded back to the AC mains ground and
this should be done outside of the house.
It is important to realize that it is the bonding of all coax shields
together, and of that combination to earth by a short robust path, and
of that earth connection to ALL OTHER EARTH connections, including
power, CATV, telco, satellite, etc. is what provides lightning primary
protection for you and your home. All that the Polyphaser does is short
the center conductor of the coax to the shield to protect the input and
output stages radio to which it is connected.
73, Jim K9YC
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