This is the World Wide Web's premier information source for listeners of non-broadcast "utility" radio communications using digital transmission systems rather than voice to send messages. The Information section features stations operated by the world's military, diplomatic, commercial, government, humanitarian, intelligence and other organizations, monitored from the UK and USA between the frequencies of 10kHz and 1GHz. 

The Resources section includes frequency and other databases, provides information to help identify digital signals by their sound or signal parameters, tips on finding hardware or software decoders, and some useful links to related sites.  My logbook is updated monthly, and the ALE and selcal databases almost daily, detailing more than 6,000 ALE and 2,000 selcal identifiers.

Don't forget to check the monthly "Digital Digest" column in Monitoring Times magazine. 

Please feel free to send a message to: umc at chace dash ortiz dot org if I can be of help, or if you have any comments, corrections or other information concerning these pages.