If you're on the 1 ohm scale the 400 almost certainly means 400 military ohms, aka .4 ohms.
No worries there if it reads 300 milii ohms with the leads shorted (means your cable is adding only 100 mili = .1 ohms).
You should see low ohm readings from outside ground to outside ground.
You should be OPEN from center pin to outside ground connector.
No worries there if it reads 300 milii ohms with the leads shorted (means your cable is adding only 100 mili = .1 ohms).
You should see low ohm readings from outside ground to outside ground.
You should be OPEN from center pin to outside ground connector.