SCANNER MODIFICATIONS AIS PROGRAMS

FOR DE-CODING POCSAG SIGNALS

TAKING THE OUTPUT FROM THE SCANNERS MIXER / DISCRIMINATOR CHIP IS BECOMING VERY POPULAR WITH CLAIMED BETTER DECODING OF SIGNALS, IF YOU OPT FOR THIS METHOD YOU WILL BE ABLE TO UTILISE A HAMCOMM TYPE CIRCUIT   - IF YOU TAKE THE SIGNAL FROM THE SCANNERS HEADPHONE SOCKET , THEN YOU WILL NEED TO BUILD THE POCSAG CIRCUIT - NOT A LOT OF DIFFERENCE IN THE CIRCUIT, THE POCSAG CIRCUIT HAVING AN EXTRA RESISTOR.THE MODIFICATION TO TAKE AN OUTPUT FROM THE DISCRIMINATOR  CHIP IS BASICALLY VERY SIMPLE - BUT LIKE ALL SUPPOSEDLY SIMPLE THINGS IT CAN GO WRONG - DO NOT ATTEMPT THIS MODIFICATION IF YOU ARE NOT 100 % CONFIDENT ABOUT IT - OR INDEED IF THE SCANNER IS STILL UNDER WARRANTY .YOU NEED TO FIND WHICH PIN CARRIES THE AUDIO OUTPUT FROM THE MIXER / DISCRIMINATOR CHIP, AND CONNECT A LENGTH OF MINIATURE CO-AX OR SCREENED CABLE TO IT VIA A 0.1mF CAPACITOR .THE OTHER END OF WHICH GOES TO YOUR HAMCOMM OR OTHER TYPE INTERFACE CIRCUIT.THE ABOVE INFORMATION IS FOR  GETTING THE SIGNAL INTO THE COMPUTER SERIEL PORT.

SHIPPLOTTER

ALSO IF YOU ARE RUNNING THE SHIPPLOTTER PROGRAM FOR AIS (THE SHIP AUTOMATIC IDENTIFICATION SYSTEM ) BETTER DE-CODING WILL RESULT IN YOU TAKING THE OUTPUT FROM THE DISCRIMINATOR.

THE BELOW TABLES SHOWS SOME CHIP OUTPUT PIN NUMBERS - YOU NEED TO IDENTIFY  WITH 100% ACCURACY THE CHIP IN YOUR SCANNER AND THE CORRECT AUDIO BASE PIN BEFORE EVEN THINKING ABOUT DOING THIS MODIFICATION.IF IN DOUBT - DON'T DO IT !

  FOR FURTHER CHIPS/SCANNERS TAKE A LOOK AT THIS LINK http://www.discriminator.nl/ic/index.html