Suggestions for a good digital converter box for maximum 4:3 format screen fill

[Chris K]

Hi guys...looking for suggestions for a digital converter box useable with a vintage antenna and has a coax RF output and a screen filling or almost screen filling picture setting for the vintage 4:3 video ratio. Also, how much do you mess with a vintage TV's width and height settings for a round tube TV to maximize screen fill. My box does have ratio settings for 4:3 screen fill but it's not even close. It's a cheap Chinese unit so I didn't expect much but when I watch YT restorations, the final image restorers get is much larger than I have been able to get with my equipment. Additionally, it's obvious some of these converters are better than others for noise/buzz suppression associated with modern format so some suggestions there would also be appreciated.