[RFI] DigiKeyer II

Jim Brown jim at audiosystemsgroup.com
Thu Dec 19 18:14:44 EST 2013

On 12/19/2013 2:41 PM, Dale J. wrote:
> So we should now bond each box to each other


> using a wide flat strap or copper mesh (shield copper) from RG8 or equivalent,

Wide flat strip is overkill, but certainly OK. The copper braid from 
transmitting coax is typically equivalent to #12-#10 copper. As others 
have noted, braid is fine inside, a train wreck outside.

> then take that total bonding to a station ground such as a ground stake outside  using large solid copper wire or to copper water piping inside the house with the braid or strapping and bypassing around the water meter, for lightning protection?

All of the above. Good engineering practice, as well as electrical 
building codes in most of the civilized world, both require that all 
grounds in a premises (home, biz, building, etc.) be bonded together. 
That includes our station operating desk, antennas, CATV entry, telco 
entry, power system entry, building steel if there is any, cold water if 
it's metallic, all driven rods, and so on. From a lightning protection 
point of view, the safest system has all external cables entering the 
premises at the same point, but that often doesn't happen, especially in 
older buildings. It's pretty common for newer homes here in NorCal to 
have power, CATV, and telco all entering at the same point, often 
underground. Many older homes have cables entering at widely separated 
points, so bonding conductors must be much longer.  In general, we can 
have as many connections to earth as we want, but they must all be 
bonded together, and the shortest practical path is generally best.

73, Jim K9YC

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