Except that "ground" isn't actually some sort of sink for RF. Imagine a
portable battery operated setup with a dipole antenna and nothing about
the rig connected to ground. A common mode choke will do its job ... a
connection from the coax shield to ground doesn't do a thing.
Dave AB7E
On 9/27/2025 12:31 AM, Brian Beezley wrote:
"This one bothers me. Remember that there really is no such thing as
ground for RF - that ground rod is strictly for lightning / static
currents. Connecting the shield to a “grounding point” will simply
combine the inner and outer currents. That’s really not what we want
to do. You need instead to choke off the RF current on the outside of
the shield."
Jack, I do not assume that a ground connection has 0 ohms RF
impedance. All I was looking for was a low impedance to shunt off most
of the coax shield current. Shield current splits at a junction. If
the impedance looking toward the ground point is lower than that
looking toward the shack, it will carry most of the current. If it is
much lower, it should keep nearly all of it out of the shack.
Brian
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