This tool was developed to help visualize the effects of narrowbanding a VHF communications system. It shows adjacent channel overlap before and after narrowbanding, for both analog and digital systems. Use at your own risk.VHF Narrowbanding Tool
Here are some slides illustrating some issues with programming older VHF radios on the "new" narrowband splinter channels:
Not really related directly to narrowbanding, and not really a chart, this is a spreadsheet that contains data from the FCC Part 90 frequency tables that shows how public safety and business channels are interleaved in these bands. This is a starting point only. It only includes data from the "main" Part 90 tables and doesn't (yet) include misc. frequencies like the "hydro" channels or 420 MHz spectrum in some geographical areas. Channel bandwidths are also not to scale. I may add more detail/accuracy as time permits.
Links to more narrowbanding resources can be found on my Radio Training page.