RadioReference on Facebook   RadioReference on Twitter   RadioReference Blog
Wiki Home
View source

Personal Tools

Search the Wiki


Discriminator output

The Discriminator output from a scanner is the raw, unfiltered signal that a scanner produces before it is sent to the audio stage for output through the speaker -- also called the "baseband audio." This discriminator source is required for applications such as Trunker, T4Win, UniTrunker, and DSD. Most scanners must have a simple modification made to them to feed the discriminator output to Data Slicers, or in the case of UniTrunker, a soundcard.

Note that for providing a signal for ACARS decoding, a connection from an earphone or speaker output is all that's required. This is because ACARS runs at a much lower speed, and the discriminator is not involved in AM reception.


Also see the Scandata faq q2 article for a list of older scanners' tap points. This is from an original article by the late Bill Cheek.


  • BC-396T Discriminator Tap
    • NOTE: You must be a member of the BCD396T Yahoo to view this message.
    • The JPEG for the discriminator tap can be viewed here

Radio Shack

Other Radios

Why use a resistor and/or capacitor ?

See #6 through 8 of this URL: FAQ

Wikipedia Page showing Circuit and calculations for Discriminator Tap.


These pages or links contain more information on discriminator taps for many brands and models of scanners, including older models

Copyright 2015 by LLC Privacy Policy  |  Terms and Conditions