The Radio-Stuff CMC is designed to supress unwanted electromagnetic interference (EMI) or radio frequency interference (RFI).
 
Suitable for high-frequency (HF) applications from 80m to 10m bands. Designed to suppress common mode currents and interference/noise on your coax.
 
Impedance greater than -30db across the 80m to 10m range.
Low insertion loss.
400w power handling capability.
ABS sealed case with quality SO239 connectors.
Built with a Fair-Rite T240-43, Type 31 core available on request.
 
Our HF common mode choke is designed to attenuate common mode noise and improve your signal quality therefore improving the signal to noise ratio on reception.
 
This choke is designed to be placed either below your antenna, to isolate the antenna from your coax. 
 
Or, if you are using an EFHW you should place the CMC at .05 wave length below the EFHW transformer. 
 
Ideally you should have a CMC at both the antenna and shack side, for every antenna in use.