Here is a web site that I am adding to my links on the blog and one that you should be checking into if radio is one of your hobbies. The Radio Reference Home Page
has so much information it will take a while for you to digest even part of it. It is of particular interest if you are interested in trunked scanner monitoring. There are complete databases of frequencies and talk groups for just about anywhere you want to listen in on.
In addition there are over one hundred thousand postings in their discussion forums. A real wealth of knowledge that can be tapped into with just your web browser. Everything from HF listening to trunked VHF/UHF two way systems. A highly recommended web resource.