|
Usually when there's a coax from the antenna board to the tuner it's 75ohms (there are exceptions).
There's probably* no harm in trying to unplug the antenna board RCA cable from the tuner and connecting an RCA to F-type coax adapter.
*Some TVs are hot chassis and there could be 120V on the shield of the tuner and it's antenna... Before connecting the 2 I would measure the AC and DC voltage between them and if either is over 10V I'd avoid connecting them directly.
|