As you may have found Japan uses different FM radio frequency (76-90) to Australia (88-108). There is a solution for this, a convert sometimes referred to as “band expander” or “frequency shifter”. These change the incoming radio frequency by 20, so for example, your radio shows 81.7 but receives a station on 101.7 These a readily available on Ebay, many coming from the UK. Most Jap imports will have had one of these fitted long ago so test your radio before buying one.
