[ICOM] Icom, Grounds and Mikes

[Sheldon Daitch]

Groud loops occur when the impedances of the grounding 
paths are not zero, which, will not happen.

In your example, Jerry, you have a two ground paths, one 
is the ground path between a piece of equipment, the 
chassis ground, going to your SGP.  There is a second
ground path, the one between the chassis, via the 
safety ground of the power cord, to your electrical 
service box, then to the AC service ground.  The two 
paths have difference impedances and thus there will 
be potential differences between them.  That makes up
the ground loop problem.

In most cases, you never know about it, but with 
sensitive audio equipment, it many times presents
problems with hum levels.

73
Sheldon
WA4MZZ



Jerry Keller wrote:
> 
> Dave... I have all my equipment chassis-grounded to a single copper bus that connects directly to a single point ground (large copper plate in a box) at the entry point to the shack. All of the equipment AC power cords are three-prong. Every coax line is grounded at the SPG and at the feedpoint. The SPG is bonded to a peripheral ground line that encircles the house and is bonded to the AC service ground. There are ground rods every 15 - 20 feet along the peripheral ground. The vertical and tower grounds are all bonded to the SPG. Seems to me this combines all power and RF grounds into a single common system with none of those "audio loops" you mention. Would you agree? If not, where do you see a problem?
> 
> Any critical help or suggestions appreciated, 73 Jerry K3BZ
>