On 4/5/2011 7:59 AM, Bill, W6WRT wrote:
> REPLY:
>
> If you are getting RF in the shack, you do not have a grounding problem,
> you have an antenna problem. You do NOT need an RF ground at your shack
> in any way. The only grounds your shack needs are for safety of the AC
> mains and for lightning.
>
> RF in the shack problems indicate an unbalance in the antenna and/or
> feedline system and can almost always be cured by proper application of
> a balun or unun.
>
> RF energy is expensive to generate. Do not waste it by running it
> through dirt. Get it up in the air where it belongs.
RIGHT!
Back to Charles's question about which ground is better. The answer is
that it doesn't matter -- ALL MUST BE BONDED TOGETHER, which makes them
effectively in parallel. In addition to lowering the impedance to
earth, that also reduces the potential difference between different
points in your building in the event of a lightning event, which in turn
minimizes the likelihood that something is going to fry.
As to the power company's ground rods -- THEY DON'T MATTER! LIGHTNING IS
NOT A DC EVENT, it is an IMPULSE, with VERY STRONG harmonics. The energy
in lightning is broadly centered around 1 MHz, so what matters is the
IMPEDANCE of the path to ground, which, if you do the arithmetic, is
dominated by the INDUCTANCE of the connecting wires.
73, Jim Brown K9YC
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