[RFI] DigiKeyer II
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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