Panasonic RF3100
 

I’m trying to figure out whether or not I connect the centre conductor of the Rg58 RF coax cable from my atu to the far left clip socket on the rear of the RF3100 receiver, or the far right clip socket on the rear of the Panasonic RF3100 receiver as seen from the rear of the receiver. The centre being the ground terminal for the ground and screen of the coax downlead.

I use a 9:1 UnUn before the 50ohm coax at the long wire end thus matching the antenna to the longwire hopefully.. But which of the two terminals should I connect to? If I connect to the high impedance terminal then I select High on the switch selection and if I connect to the Low impedance terminal then I select Low on the switch selection. The switches are aligned to the inputs, I found out that part. But is my antenna set up low or High impedance? At which point does an antenna become High Impedance? The actual operating manual is not clear as to which terminal to connect to as it shows 75ohms FM antenna on the high impedance terminal and the long wire on low impedance but doesn't include an UnUn 9:1 in any diagram. very confusing. has anyone got the answer to this puzzle?