[TowerTalk] Feedline (choke) question

[Jim Brown]

On 10/1/2025 7:46 AM, Jack Brindle via TowerTalk wrote:
> Connectors are very important in this system. They must be added to the analysis. Without them, we have to question the validity of the tests.

No. Common mode and differential mode currents are a characteristic of 
transmission lines, and common mode can be present on 2-wire lines if 
the system that includes the antenna, the transmission line, and 
termination in the shack has imbalance. The mechanism by which common 
mode in coaxial line is on the outside of the shield is skin effect, and 
it's present in those connectors.

Soldered or crimped, the connector(s) is/are simply part of the 
transmission line, carrying the differential and common mode current 
that is in that system (antenna, line, shack). Depending on their 
construction, they can introduce some discontinuity in the differential 
circuit.

73, Jim K9YC