Weirdness. Playing with my version of the latest SW, I can get it to accept some narrow channels, and not others. It looks like only every 5th narrow channel will work.V2.2 was the last software release, copyright 2001, before the 'Plan' was really a plan.
Sorry to say this, but the F3's are getting long in the tooth. Ebay it to an amature and move on.
Knowledge Base Article 74IC354553
Issue: F3G / F4G Wide or Narrow - How can I tell if my F3G or F4G is wideband or narrowband?
Resolution: F3G Model numbers 86 and 87 are switchable for wide and narrow; F4G model number 90 is switchable for wide and narrow. All other models are narrowband only. If you don't know the model number of your radio, Service dealers can see it on the PCB when you remove the option cover.