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.

Modifications

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.

Uniden

• BC-245 Discriminator Tap
• JPEGs of BC246 discrim tap
• BC296D/UBC 3300XLT
• BC350A Discriminator Tap
• 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

• BC-780 Discriminator Tap
• BC785D Discriminator Tap
• BC796D Discriminator Tap
• BC895XLT Discriminator Tap
• BCD996 Discriminator tap point
• BCT15 Discriminator tap point
• NOTE: Look dead center of the circuit board, then go right and down. Both the 996 and BCT15 appear to share the same tap point location.

Radio Shack

• Pro-93 Discriminator Tap
• Pro-95 Discriminator Tap
• Pro-96 Discriminator Tap
• Pro 97 Discriminator Tap
• Pro-106 Discriminator Tap
• Pro-164 Discriminator Tap
• Pro-2052 Discriminator Tap
• Pro-2053 Discriminator Tap

Other Radios

• PSR-500 Discriminator
• R7100 Discriminator Tap Notes

Why use a resistor and/or capacitor ?

See #6 through 8 of this URL: Discriminator.nl FAQ

Links

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

• Discriminator NL
• Mods DK
• RadioModifications Yahoo Group
• ScannerTech Yahoo Group
• SCANDATA.FAQ