[TowerTalk] Feedline (choke) question

[David Gilbert]

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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