[TenTec] Single point grounding preferable

[Stuart Rohre]

Some thoughts on grounding and ground loops.

The Astron does indeed float the negative lead.  IF you were to ground it at
the Astron, you create a ground loop with the AC green wire which IS grounded
to the chassis.

The place to ground all together is at the ground post of the rig, with a
short bond to the transmatch chassis as well.  This establishes single point
of grounding, which then goes by the shortest possible path to earth.

Now, if your shack is interior to house, you might have to bond to a metal
water pipe in or on the other side of the wall, or some other accommodation.
Such a bond will not always reduce RF in the shack.  That comes about when the
total run of grounding is an odd multiple of a quarter wave at some band
having the RF in the shack problem.
Thus, bonding to earth is mainly a lightning and shock safety procedure.
Short bonding of the rig and accessories addresses RF problems, but sometimes
a quarter wave counterpoise cut for each of the problem RF bands is needed to
tame the RF character of your single point ground.

The best way to avoid problems with RF in the shack is not to bring single
ended antenna leads in, such as the "random" wire.  A center fed doublet
antenna is the most benign as to RF in the shack problems.  This can be a half
wave dipole, or a transmatch and ladder line fed Extended Double Zepp for all
bands.  Coax fed antennas whether balanced or unbalanced, such as base fed
verticals, may need special handling if the coax becomes an odd multiple of a
quarter wave at your frequency.  Usually adding 5 or 10 feet of coax moves
such resonances out of the band where it is not a problem.
73 Stuart K5KVH


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