US Federal Communications Commission
http://www.fcc.gov

US AM Broadcast Query by Call Sign or File No.
http://www.fcc.gov/mb/audio/amq.html

US FM Broadcast Query by Call Sign or File No.
http://www.fcc.gov/mb/audio/fmq.html

US TV Broadcast Query by Call Sign or File No.
http://www.fcc.gov/encyclopedia/tv-query-broadcast-station-search

US Environmental Protection Agency –
www.epa.gov

Canadian Navcanada (operates Canada’s civil air navigational system –
www.navcanada.ca

National Telecommunications Information Administration
http://www.ntia.doc.gov

Federal Aviation Administration
http://www.faa.gov