Jack,

The classic ground loop can occur even when individual components are
perfectly bonded to a single point ground. The "loop" is formed when a
signal cable connects the bonded components together along an alternate
path. There are many proper fixes for this problem, but one popular
quick and dirty fix is to disconnect the bonding by removing the third
pin on the power plugs. Not a good idea, but it happens a lot.

If correcting ground loops was simply a matter of properly bonding the
components to a single point then nobody would ever bother mentioning
ground loops.

73,
Gene
W4SZ

Jack Painter wrote:

[snip]


It's my understanding that ground loops are most common from having serial
v. parallel connections to ground from various equipments. Daisy-chaining a
series of radios to the common ground would thus allow radios to exhibit
feedback through each other instead of only to ground. When a properly
bonded system is connected (each unit indivdually connected to the single
point ground) there is no ground loop. Others often ask what about multiple
bonding-points of the external ground system and it's connection to the AC
mains? Answer: These are not ground loops and are not the cause of equipment
interference from the series-connections of equipments described above.