[RFI] Old wives tail, or true?

[Dave Cole]

Hi,

I have heard from several folks here, and elsewhere that one can gauge 
the amount of common mode noise on their coax by unscrewing the shield, 
at the radio, and leaving the center in place, while pulling the center 
out slightly to disconnect the shield from the radio, while listing.

If there is a change in noise level, up or down, it is said that 
indicates common mode issues...

Is this true, and if so, why?

-- 
73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources