"Buck" wrote

I get a lot of flack when I mention using a ground for my radio and
antenna because of electrical code. I don't believe that my station
causes a ground loop because of it's design, but there is the issue
for other places as well.

First of all, I have a deep cycle battery for a power supply for my
Icom 706 MKII. I use a smart charger to keep the battery charged.
The charger only uses two wires. The radio is grounded through a
lightning/static arrestor by way of the outer brass casing that screws
into the SO-239 connector on the radio. My ground is a copper pipe
stuck about 5 or 6 feet deep next to the window where the radio is
located. A large wire goes from the radio to the ground-rod.

The reason I feel this does not create a ground loop, is that the only
electricity is run through an isolation transformer (the charger) to
the twelve volt battery which powers only the rig and an emergency
light.

However, there are others with this issue. Assuming they have
'normal' stations, they are likely to have a 3-wire grounded power
supply or a radio with a grounded power supply built in. For these
people (and possibly me in the future) I am wondering about the best
means of a ground especially when the rig is far away from the
electrical panel.

My thought is to run a solid #8 wire underground from the electrical
ground rod to the closest point to the radio. There, set an 8 foot
ground rod giving a close to zero loss from the radio ground to the
electrical ground. The fact that the copper lead between the two rods
is buried will only improve the radio ground rather than create a
resonant loop.

Any thoughts?

Buck
N4PGW

Hi Buck,

You do not have a ground loop or avoid one because you are on or off the
grid, or using a separate station ground system, even when bonded to the
service entrance ground as code requires.

Grounding multiple pieces of equipment in series before the common ground is
what allows ground loops. That can happen whether the building's three wire
120v system is the only ground, or a station ground is also involved. Avoid
it by not daisy-chaining the bonds of individual equipments with the station
single point ground. As awkward as it seems to individually bond equipment
to the single point ground, this is how to avoid a ground loop.
Practicality often overrides this design concept (using a bus-bar for
multiple equipment grounding, etc). But if noise could be isolated as caused
by such series-grounding, then you know how to eliminate it.

The station ground IS an awful thing to have, and a major cause of lightning
damage to the station IF it is both: 1. separate from the service entrance
ground, and 2. not properly bonded to the service entrance ground. We would
avoid most of the outdoor grounding and bonding systems required to control
this condition IF we just brought all antenna feeds into the structure AT
the service entrance ground. And then shield grounded and used arrestors
right there.

For HF-only feedlines (where an extra 40-60' of coax would add superficial
loss) there should be no excuse for not bringing all feedlines into the
structure only at the service entrance. UHF systems that suffer much higher
line loss tempt us to bring antenna feedlines directly into the radio shack.
THAT causes a major bonding headache. This is because we have to achieve
such low impedance connections to the service ground that lightning will
never choose a path up from ground, through our equipment, and out via the
house wiring to get back to the service entrance ground. We are never fully
protected from such occurrence if the station ground and service ground are
apart from each other, no matter how well they are bonded. But we can be
reasonably protected in that respect, when the bonding jumper is of
significantly lower impedance than the AC wiring in the home.

#8 copper is no where near the "significantly lower impedance" we're talking
about. Either wide copper strapping or #2 or #4 copper would be a better
example for the bonding connection between service entrance and station
ground. The more places along the way that bonding jumper is also bonded to
the outdoor antenna ground fields, radials, etc, the better. Voltage
division plays a big part when everything is bonded and many grounding
electrodes are used.

Hope this helps,
73,
Jack Painter
Virginia Beach, Virginia