Effect of Common Mode Chokes
22 Feb 2022
Common wisdom is that common-mode chokes on antenna coax cables are an effective way to prevent common-mode noise from inside the shack from propagating on the coax shield and coupling to the active element(s) of the antenna the coax cable is connected to.
In the KiwiSDR waterfall views above, it should be possible to view this effect. In particular, the 2-4 MHz area is much worse without the common-mode choke.