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Scanner Discriminator Data


From           bcheek@san.rr.com (Bill Cheek)
Organization   COMMtronics Engineering & World Scanner Report
Date           Sun, 17 May 1998 09:31:32 GMT
Newsgroups     rec.radio.scanner,alt.radio.scanner,
	       rec.radio.shortwave,rec.radio.amateur
Message-ID     <356fadde.56797273@news2.cts.com>

This article/file is for the benefit of all hobbyists.

(c) 1995-98  by
Bill Cheek and COMMtronics Engineering

This article/file is for personal use only and may NOT be placed 
on a CD-ROM nor any other media that conveys, stores, or transports 
for any monetary cost, without expressed permission of the author.
This file can only be given away, absolutely free of charge, so
long as it is conveyed unaltered and completely intact.

                                   -Bill Cheek-

NFM DISCRIMINATOR CHIPS - BASEBAND AUDIO - SCANNER DATA INTERFACE
=================================================================

There is a growing interest in tapping the baseband audio 
out of various scanners for decoding of a variety of esoteric 
signals, including CTCSS, SCA, FSK, RTTY, FAX, etc.  By and
large, such signals cannot be taken from TAPE REC jacks, 
headphone jacks, and EXT SPEAKER jacks because of the voice-band 
filtering that is done between the signal source and these 
output jacks.

Therefore, it is necessary to tap the "baseband audio" directly 
at the output of the discriminator chip for your scanner. Table 1 
shows a list of scanners, the discriminator chip(s) used in the 
scanner, circuit symbols of those chips, and three pins of general 
interest on the chips: RF-Input, Scan Control, and, of course, 
the baseband audio (discriminator output) pin.

Even though your scanner may not be listed below, try to find 
its discriminator chip, and chances are it will be listed with 
one or more scanners below, the pins of which will be the same 
for your unlisted scanner!  Corrections and  additions to this 
list are requested. See my email and other addresses at the end 
of this file.

For hookup information, see just after Table 1.

TABLE 1: SCANNER DISCRIMINATOR CHIP PINS OF INTEREST 
Updated  04/19/98
                                CKT     RF-in   SCAN  BASEBAND
SCANNER         NFM CHIP TYPE   SYMBOL  Pin     Pin   AUDIO PIN
=============== =============== ======= =====   ===== =========
unknown         MPS5071         n/a     16      13      9
AR-1000         TA-7787AF       IC-4    16     none     9
AR-2002         MC-3357P        IC-4    16      13      9
AR-2500		TA-7761P	IC-13	16		9
AR-3000         MC-3357P        ?       16      13      9
AR-800          MC-3361N        IC-200  16      13      9
AR-900          MC-3361N        IC-201  16      13      9
AR-950          MC-3361N        IC-201  16      13      9
AR-8000 NFM     TK10489M or-85M U1      20     16-17   11
AR-8000 WFM/AM  TA7792F         U3      16       -      8
BC-100XL        MC-3359P        IC-1    18      15     10
BC-100XLT       TK-10421M-2     IC-401  20      16     11
BC-140XLT       MC-3359P        IC-1    18      15     10 *
BC-200XLT       TK-10421M-2     IC-401  20      16     11
BC-205XLT       TK-10421M-2     IC-401  20      16     11
BC-250          ?               IC-3    16      13      9
BC-2500XLT      TK-10930VTL     IC-201  24      -    12-FM  13-AM
BC-3000 NFM/AM  TK-10930V       IC-202  24      -    12-NFM 13-AM
BC-3000 WFM     TK-10489M       IC-203  20     16-17   11
BC-350A         NJM-3359D-A     IC-3    18      15     10
BC-400XLT       NJM-3359D-A     IC-1    18      15     10
BC-560XLT       NJM-3359D-A     IC-1    18      15     10
BC-700A         NJM-3359D-A     IC-3    18      15     10
BC-760XLT       NJM-3359D-A     IC-2    18      15     10
BC-800XLT       MC-3359P        IC-1    18      15     10
BC-235XLT       MC3361CDR2      IC-2    16      13      9 *
BC-8500XLT      MC-3361BP       IC-9    16      13      9
BC-855XLT       TK-10421M-2     IC-401  20      16     11
BC-890XLT       NJM-3359D-A     IC-3    18      15     10
BC-895XLT       MC13371         IC-3    ?        ?      9 *
BC-950XLT       NJM-3359D-A     IC-2    18      15     10
HX-1000         TK-10420        U-201   16      13      9
MR-8100         NJM-3359D-A     IC-3    18      15     10
MX-5000         MC-3357P        IC-4    16      13      9
MX-7000         MC-3357P        IC-4    16      13      9
PRO-2002        MC-3357P        IC-101  16      13      9
PRO-2003        MC-3357P        IC-104  16      13      9
PRO-2004 NFM/AM TK-10420        IC-2    16      13      9 (TP4)
PRO-2004 WFM    KB4419A         IC-1    1       -       6 (TP3)
PRO-2005 NFM/AM TK-10420        IC-2    16      13      9 (TP2)
PRO-2005 WFM    KA2243N/HA12413 IC-1    1       -      10 (TP1)
PRO-2006 NFM/AM TK-10420        IC-2    16      13      9 (TP2)
PRO-2006 WFM    KA2243N/HA12413 IC-1    1       -      10 (TP1)
PRO-2011        TK-10420        IC-1    16      13      9
PRO-2020        MC-3357P        IC-101  16      13      9
PRO-2021        TK-10420        IC-2    16      13      9
PRO-2022        MC-3361N        IC-1    16      13      9
PRO-2023        NJM-3359D-A       ?     18      15     10
PRO-2024        MC-3361N        IC-2    16      13      9
PRO-2025        NJM-3359D-A     IC-1    18      15     10
PRO-2026        NJM-3359D-A     IC-7    18      15     10
PRO-2027        MC-3361N        IC-2    16      13      9
PRO-2028        NJM-3359D-A     IC-2    18      15     10
PRO-2030        NJM-3359D-A     IC-3    18      15     10
PRO-2032	MC-3361         IC-2    16      13      9 (TP5)
PRO-2035 NFM/AM TK-10420        IC-2    16      13      9 (TP2)
PRO-2035 WFM    KA2243N/HA12413 IC-1    1       -      10 (TP1)
PRO-2041        MC3361N         IC-301  16      13      9  *
PRO-2042 NFM/AM TK-10420        IC-2    16      13      9 (TP2)
PRO-2042 WFM    KA2243N/HA12413 IC-1    1       -      10 (TP1)
PRO-2050        MC3361CDR2      IC-2    16      13      9  *
PRO-23          MC-3361BD       IC-1    16      13      9
PRO-26 NFM/AM   TK-10930V       IC-14   24      -    12-NFM 13-AM
PRO-26 WFM      TK-10489M       IC-16   20     16-17   11
PRO-31          TK-10420        IC-1    16      13      9
PRO-32          TK-10420        IC-101  16      13      9
PRO-34          TK-10420        IC-101  16      13      9
PRO-35          TK-10421M-2     IC-401  20      16     11
PRO-36          TK-10420        IC-101  16      13      9
PRO-37          TK-10420        IC-101  16      13      9 (TP103)
PRO-38          MC-3359P        IC-1    18      15     10
PRO-39          MC-3361N        IC-201  16      13      9
PRO-41          MC-3359P        IC-1    18      15     10
PRO-42          MC-3361N        IC-2    16      13      9
PRO-43          TK-10427/-10420 IC-301  16      13      9
PRO-44          MC-3361N        IC-201  16      13      9
PRO-46          TK-10421M-3LT   IC-401  20      16     11
PRO-49          MC3361BP        IC-2    16      13      9
PRO-51          MC-3361BD       IC-1    16      13      9
PRO-60          ?               IC-301  16      13      9
PRO-62          KA3361          IC-301  16      13      9  *
PRO-64          MC3361N         IC-301  16      13      9
PRO-66          MC3361N         IC-2    16      13      9 (TP3) *
PRO-90          MC3361CDR2      IC-2    16      13      9
Icom R-1 NFM	TK-10487  DET-A IC-1	20      Q1     11
Icom R-1 WFM	TA-7787AF DET-B IC-1	16       7      9   
Icom R7100	Said to be "top of R230 on the top of main PCB"  *
R-1600          NJM-3359D-A     IC-2    18      15     10
R-4030          TK-10421M-2     IC-401  20      16     11
SR-15           TK-10421D-2     IC-1    16      13      9
StandardCCR708A TK-10420D	Q602    16      13      9 *
TurboScan 2     3130-6056-502   U-201   18      ?     10 or 16
WiNRADiO  NFM   MC-3372D        U2      16      14 Mute 9 TP20
WiNRADiO AM/WFM TA-7640AP       U5       -       -      9 TP29
WiNRADiO  SSB   LM324M          U6       -       -      1 
Yaesu FRG-9600  MC-3357P        ?       16      13      9 *
==================================================================
* Not personally verified by me

HOOKUP PROCEDURE
================

If you need the raw Discriminator baseband audio signal for
external purposes, the best way to access it is via a jack
installed in a convenient, unobtrusive location on the scanner.

1A  BASE SCANNERS: Install an RCA or other jack in a desired place 
    on the scanner's external case, typically the rear panel.  

1B  HANDHELD SCANNERS: If you can find the space, use a standard
    monaural 1/8" phone jack or a 3/32" mini phone jack.  Some
    scanner are so cramped inside that even these won't fit. In
    that case a strip of 3 pinline sockets can be melted into 
    the plastic case and wires soldered to the inside protrusions. 
    The middle pinline socket is not connected to anything; it's 
    just there as strength and support for the pinline plug you 
    make, with the shield ground soldered to one end and the audio-
    center soldered to the other end:  GND---o o o---NFM DSCR (audio)

    "Break-apart" pinline plugs/sockets are available from Mouser,
    DigiKey, and Hosfelt.  These little puppies are good for a
    lot of hacker needs, so get a supply!

2.  Connect the shell or outer frame part of the jack to scanner 
    chassis ground.  (Use one end socket for pinline connections)

3.  Connect the (+) leg of a 2.2-uF to 4.7-uF tantalum capacitor 
    to the Discriminator output Pin. (Capacitor should be tantalum,
    but can vary in value from 1.0-uF to 10-uF at a voltage
    rating of 16-35 vdc.)

4.  Connect the center conductor of a shielded coax (RG-174, etc) 
    or shielded mic cable to the (-) leg of the capacitor.  NOTE:
    if the distance from the NFM tap to the jack is less than 3",
    then a single unshielded hookup wire will do fine.

5.  Connect the shield of the cable at this end to a nearby PCB 
    ground trace or spot.  

6.  Connect the center conductor of the other end of this cable 
    (or single hookup wire) to the center or hot lug of the jack.  

7.  Connect the shield of the cable at that end to the ground lug 
    of the jack.  

8.  Fabricate or buy a shielded patch cable with one end to mate 
    with the new jack on the rear of the scanner at that end....and 
    the other end to mate with whatever jack is on the tape recorder, 
    processor, decoder, or whatever device is to be connected at the
    other end.

If you want to decode trunk control, MDT, pager, fax or other 
digital signals, you will need a special Interface between 
the NFM Discriminator/baseband audio of the scanner to the PC's 
serial port.  Following is a tried and true Data Interface circuit 
that is good for everything we've tried, including a wide variety
of scanners.

            SCANNER DATA INTERFACE SCHEMATIC DIAGRAM
Copyright (c) 1998 Bill Cheek

                                                  Computer
                                                 Serial Port
Scanner  |<------circuit----------------->|      DB25    DB9
                                                 ====    ===
                          o----o--|<------------->20 DTR  4
      0.1 to              |    | 1N4148
NFM   0.5-uF         |\   |    o--|<----------o--> 4 RTS  7
 >------]|+-----o----|2 \ |    |              |
DSCR            |    |    \    o--+|[--->>>   |
        100k    |    |LM  7 \     10-uF       |  
 >--o--/\/\/----o    |741  6 >----------o-----|--> 5 CTS  8
GND |                |      /           |     |
    o--/\/\/--o------|3  4/             |     |
    |   3.3k  |      |  / |             |     |
    |         |      |/   |             |     |
    |         o-----------|----/\/\/----o     |
    |                     |     100k          |
    |                     |                   | 
    o---------------------|-------------------|--> 7 Gnd  5
    |                     |                   |
    |            10-uF    |                   |
    o-------------+|[-----o-------->|---------o
    |                     |      1N4148
    o--->>>Ground         o-------->|------------> 2 TxD  3


 LEGEND:
       o = soldered connection/junction
   --|-- = crossover (no connection)
     +|[ = capacitor, polarized (see +)
      >| = diode (anode->|-cathode)
      |< = diode (cathode-|<-anode)
 -/\/\/- = resistor
   -->>> = ground
 
 NOTES:
 1.  Use tantalum capacitors, +|[ polarity as shown

 2.  Radio Shack's LM-741 works fine.  Others might not!

 3.  Use 1/4 or 1/8 watt resistors to save space 

 4.  Build circuit on a trimmed and fitted piece of perf
     board inside a DB-25 shell for max efficiency and space 
     savings. DB-25 connects to PC's comport and a shielded 
     cable from the scanner goes to the inputs, shield is 
     ground and center is audio.

 5.  Many handheld scanner have no space to install a
     phone jack for the NFM Discriminator Output.  For
     such tight spaces a strip of 3 pinline sockets can be
     melted into the plastic case and wires soldered to the
     inside protrusions. The middle pinline socket is not
     connected to anything; it's just there as strength and
     support for the pinline plug you make, with the shield
     ground soldered to one end and the audio-center soldered
     to the other end:   GND---o o o---NFM DSCR (audio)

 6.  For base scanners, install a female RCA jack on rear panel.

 7.  For handheld scanners where there is space, use a 3/32"
     mini or a 1/8" standard monaural phone plug.
 
 8.  Connect the interface to a comport on the PC.  Plug the
     input cable in to the scanner's NFM Discriminator Output
     Jack.  Tune to a desired signal and run the decoder 
     software of your choice.

=====================================================================

This article/file is copyrighted (c) 1995-98 
by Bill Cheek and COMMtronics Engineering.

Please let me have your input and feedback on the above information 
and Table, especially for additions and corrections.

Thanks,

Bill Cheek - President/CEO/Publisher              
COMMtronics Engineering/World Scanner Report
Box 262478 ~ San Diego ~ CA ~ 92196-2478
bcheek@san.rr.com    ftp://204.210.11.204
END OF FILE

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