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) 1995-98by 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
[an error occurred while processing this directive]