ARRL Ham Bands Chart - Shows each band allocation, what license is required, along with power limits, and emission types.
Reverse Beacon Network - RBN is a network of stations listening to the bands and reporting what stations they hear, when and how well. Great for seeing how well you're transmitting too.
- ITU Regions - International Telcommunications Union. Divides the world into three ITU regions for the purposes of managing the global radio spectrum. Each region has its own set of frequency allocations, the main reason for defining the regions.
- ITU Zones - Each of the regions above are further broken down into zones.
ITU Zones & Regions - A map that is a combination of the 2.
CQ Zones -
UTC Time Zones - add time zone number to local time to obtain UTC.