Good points Gene, and thanks for your reply. The AC connections could
certainly be responsible for a ground loop. But it has been my experience
that so few stations actually bond properly that the preponderance of
possibilities would occur foremost with the direct connection from improper
bonding, not the indirect connection from electrical wiring, which usually
has distance and other connections before circling back to the
offending/receiving equipment. All things need to be considered, and is a
good reason for Richard's comment that "Solving it will be one of life's
greatest struggles, and the solution, if stumbled upon, will appear to
be one of life's greatest mysteries." ;-)

I once had a ground loop from a yagi-rotor that resisted all manners of
alternative grounding, wiring, routing, rf-chokes, etc. You either put up
with it or remove it in that case!

If removing the third plug from the power cord isolated a ground loop
problem, then safer alternatives could be accomplished such as an isolated
ground and separate neutral for a particular power supply, as is common in
sensitive computer systems.

Best regards,

Jack

"Gene Fuller" wrote
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.