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, and UniTrunker. 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.

• See Bill Cheeks SCANDATA.FAQ listed at the bottom of the page for detailed instructions on how to tap the discriminator in your scanner and the locations of various tap points.
• See this document from Greg Knox regarding instructions on how to tap the discriminator output on the BC-895 Scanner. See this picture for the location of the discriminator output on the 895.
• Here are a few more sources of discriminator tap information;
  • Disciminator NL
  • Mods DK
  • RadioModifications Yahoo Group
  • ScannerTech Yahoo Group
  • BC898T Discriminator Tap