decode & encode
ITU radio frequency emissions designators

Emissions, the iPhone and iPod touch application, allows you to decode and encode International Telecommunications Union (ITU) designations of emissions.  These seven-character designators are used throughout the world to classify and identify the basic characteristics of radio emissions.

Download the free app at the iTunes App Store here:  Emissions App

Emissions is useful for anyone dealing with radio emissions, including satellite communications engineers, regulatory agency workers (FCC, NTIA, ITU), telecommunications consultants, telecommunications lawyers, amateur radio operators (hams), wireless telecommunications workers and others.

Seven-character emission designators are broken into four (4) pieces of information:

    Necessary bandwidth:

  1. Three (3) significant digits, a decimal point and a unit (Hz, kHz, MHz or GHz), all coded as four (4) characters.

    Type of Modulation:

  1. One (1) character representing the modulation type on the main carrier

    Nature of Modulation:

  1. One (1) character representing the nature of the signal or signals modulating the main carrier

    Type of Information:

  1. One (1) character representing the type of information carried by the emission.

Designator example:

  1. 36M0W7F designates a radio frequency emission that has a 36.0 MHz bandwidth, modulates the main carrier using phase modulation, has a single digital carrier without any subcarriers and will be used to carry television video.

Using Emissions

DECODE - decode 7-character ITU emissions designators into a human-readable form

Choose the DECODE tab at the bottom of the screen.

Spin the picker wheels, one by one in any order, until the pickers show the complete ITU code.  The four yellow text fields in the top half of the screen provide the interpretation.

Double-tap anywhere in the top half above the picker wheel to reset the code wheels.

ENCODE - encode the basic information about an RF information into an ITU-acceptable 7-character code.

Choose the ENCODE tab at the bottom of the screen.

Choose the piece of information to be entered by tapping anywhere on the line for the four areas. 

Spin the picker wheel(s) until they show the required description.

The purple designator at the top of the screen provides the ITU designator code that matches the current descriptions.  Be sure to choose all four areas before using the designator code.

Emissions will remember the last DECODE and ENCODE values you entered between sessions.

We welcome your comments, reviews and suggestions for future features and improvements.


  1.   ITU - The International Telecommunications Union

  2.   Wikipedia

  3.   http://www.comreg.ie/_fileupload/publications/ComReg0834.pdf