There's really no such thing as hi-def broadcast radio. HD stands for hybrid digital and refers to the digital wave that rides on the FM carrier.
There is a good resource for finding out about vintage tuners here:
http://www.fmtunerinfo.com/
In the old days WRTI used to be 24/7 jazz radio. The classical station was 95.7 (I think). They changed their format and RTI picked up their DJs and started daytime classical broadcast. There was a smooth jazz station around 106. They might have moved on the dial or changed format, I don't know. Pretty slim pickins, although RTI is good sometimes.
Regards,