[ICOM] Icom, Grounds and Mikes

[Jerry Keller]

Sheldon... I wanted all the ground circuits to rise and fall in potential equally in the event of a strike, but I guess I flunked that one :-)

What do you see that ground loop doing in the case of a lightning strike on my tower, or maybe a strike nearby that finds its way in?

Would it make any difference if I have the shack on a separate circuit, and the electric box in the shack tied direct to the SPG box? 
   
73 Jerry K3BZ
  ----- Original Message ----- 
  From: Sheldon Daitch 
  To: ICOM Reflector 
  Sent: Friday, July 30, 2004 1:01 PM
  Subject: Re: [ICOM] Icom, Grounds and Mikes


  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
  >
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