Radio DX Glossary and Q-Codes
A plain-English reference to common radio terms. Meanings can depend on context and service.
CQ
A general call inviting any station listening to respond. Exact calling practice depends on the band, mode and local convention.
QSO / QSL / QTH
QSO commonly means a contact; QSL can mean confirmation or “I acknowledge receipt”; QTH commonly refers to location.
73
A traditional sign-off meaning “best regards” or “best wishes.” It is not a literal numeric signal report.
SWR
Standing-wave ratio, a measurement related to impedance matching in a transmission line system. Low SWR does not guarantee an efficient antenna.
USB / LSB
Upper sideband and lower sideband, two forms of single-sideband operation.
Skip / skywave
Longer-distance propagation using the ionosphere. Actual paths and range depend on conditions and frequency.
QRM / QRN
Commonly used for man-made interference and natural noise respectively, though usage varies.
UTC
Coordinated Universal Time, useful for recording radio activity consistently across time zones.
Further reading
Always check current rules for the country and radio service you are using. A community convention or software feature is not proof that a transmission is authorised.
This guide is educational and may need updating as regulations, software and community information change. Check linked primary sources before relying on technical or regulatory details.