Motorola® MICOR® Information Index

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Conversion Index
"The Motorola MICOR Conversion Site"
Most of the information presented on this site was compiled by
Kevin Custer W3KKC and is Copyright © 1995 - present, all rights reserved

If you are at all serious about MICORs you will want
to subscribe to the MICOR email information list !

Note that in Motorola's product line you have either a "mobile" or a "station",
and the latter is a fixed station - either a base or a repeater.

How to identify your MICOR Mobiles are on the top, scroll down for stations
Here's a simpler MICOR Mobile identification table

Jump to: Generic MICOR (both Mobile and Station) Read this section first

Generic Station Information Low-Band Station High-Band Station UHF Station

Generic Mobile Information Low-Band Mobile High-Band Mobile UHF Mobile

Channel Element Info 222 MHz. Conversion Packet Other Information Images

Custom Built Repeaters

Useful MICOR Manuals Click here for how to order manuals
Motorola made a separate manual for each frequency range, and instead of duplicating all the pages on the control shelf in each one they combined all the non-frequelcy sensitive sections into a separate manual. To work on your base or repeater you will need BOTH the "Control and Applications Manual" AND the appropriate RF manual. If you have a community repeater you will need that supplement. If you have a secure station you will need that supplement.

Base and Repeater Control and Applications Manual 68-81025E60 (non-RF information common to all stations)

Compa-Station Base & Repeater Radio 25-50 MHz 100 watts 68-81013E60 (Low Band)

Compa-Station Base Radio Remote Control 132-174 MHz 68-81013E65 (High Band)

Base and Repeater Station 450-470 or 470-512MHz 68-81025E50 (UHF)

Community Repeater Station Supplement 68-81025E55, This is a supplement to the standard Control and Applications manual. You will need this supplement if you have the "Community Repeater" backplane and / or modules. There are several differences between a standard repeater configuration and the community repeater configuration (even if you are going to run only one PL tone, or even in carrier squelch mode)

Mobile UHF (standard and wide spaced): 68P81015E70

Mobile high band manual: 68P81008E40
Mobile high band wide-spaced supplement: 68P81014E15 (see note below)

Mobile Low Band manual: 68P81008E35

MICOR era radios have relatively narrow RF bandwidth. The maximum separation between two transmit frequencies in a standard high band MICOR is spec'd in the manual at 1.5 MHz, however, according to an original MICOR design engineer at Motorola, the exciter is capable of operating 3 MHz wide if it is center tuned 1 MHz above the lowest frequency. The wide-spaced mobile series offered variations with wide-spaced receive, or transmit, or both. The wide-spaced receiver has a second oscillator / multiplier and front end, the wide-spaced transmitter has a second exciter multiplier chain, thus one high band radio can have two 1.5 MHz (3 MHz) wide windows separated by up to 12 MHz from each other, and the channel switch selects the appropriate front end or exciter as well as which channel element. The high band wide-spaced supplement is 68P81014E15 (note that the main high band mobile manual is 68P81008E40 - you will need both manuals for your wide-spaced radio). The wide-spaced manual also has the information on the high-band extender-equipped receivers. The regular UHF mobile manual has both the standard and the wide-spaced info.

SpectraTAC voting receivers also use MICOR boards. Information on these can now be found on their own web page.

MICOR receiver and audio boards were used in other equipment too. More information can be found on the MSF & PURC page. Look for articles on the PURC5000 link receiver.

Information Relevant to Both MICOR Mobile and Station:

The MICOR Squelch Explanation of the MICOR® Bi-Level Squelch. By Kevin Custer W3KKC

MICOR® based squelch circuit A SEITS article

Explanation of Reverse Burst & "And" Squelch By Kevin Custer W3KKC

Pre-emphasis, de-emphasis, clipping, and audio quality in the MICOR By Paul Sexauer K3VIX

MICOR Muteboard®, muting audio filter amplifier By Kevin Custer W3KKC

Modification of the MICOR PL Encoder In some situations you want to disable the reverse-burst capability By Kevin Custer W3KKC

COS Logic Level Inverter A simple circuit to make positive logic COS from the audio-squelch board for those controllers that require it By Kevin Custer W3KKC

MICOR® discriminator buffer amplifier Great for NHRC, MCC, and other newer style controllers that mute and have de-emphasis built in

MICOR® PL® filter By Kevin Custer W3KKC

An "S-Meter" for the MICOR Receiver While this circuit was originally developed to allow a repeater receiver to drive an analog input of an ACC repeater controller there is no reason that it couldn't drive a different brand of repeater controller or even a meter...

Schematic of the TLN-4310B-2 mobile audio-squelch board scanned from the mobile manual
This is oriented horizontally, for viewing on your screen.

Schematic of the TLN-4310B-2 mobile audio-squelch board scanned from the mobile manual
This is oriented vertically, for printing (you will probably want to print it on legal paper, as it is an extended length diagram. If you are going to do any bench work, I'd suggest printing it on 11x17 paper.

Information on MICOR Channel Elements By M. Scott Zimmerman

Non-Band-Specific Station Information:
Notes:
1) The controller connection articles are also applicable to other brands of controllers...
2) There are several different backplanes - the "standard" one (TLN5644 series), the "community repeater" one (TRN6421 series), the Digital Voice Privacy (DVP) "secure" one (TLN5979 series), the "PURC" or paging one (don't have that number), etc. Before you start doing mods make sure that you have the proper books and the proper schematic(s). There is a list of manuals near the top of this page.
3) The mobile audio-squelch board is model number TLN4310A or B. The station A-S board is model TLN6006A or B. If you find a A-S board stamped TRN5716APR (actually TRN5716 followed by anything) you have one that came out of a 900 MHz Micor mobile, and these boards are different as the 900MHz radios use 2.5 KHz deviation where low band, high band, UHF and 800 MHz use 5 KHz deviation. Anyone that runs 900 MHz Micor radios will be happy to trade you for that TRN5716 series board.

Comprehensive conversion of the MICOR® Compa-Station base/repeater station By Kevin Custer W3KKC

Synthesize your MICOR Station By Greg Carttar (ex-WAØLCZ) of 3rd St. R & D Production Services (offsite link)

Modification of the MICOR PL Encoder In some situations you want to disable the reverse-burst capability By Kevin Custer W3KKC

Notes on how to simply connect a generic repeater controller to a MICOR station By M. Scott Zimmerman N3XCC

An IDer for the MICOR Repeater Shelf By Jerry Matthews WAØUZI
Useful to the commercial repeaters as the amateur radio repeater controllers have built-in ID'ers. While an IDer is not required for GMRS, it's a good idea and this article is relevant there as well.

One method of connection of a repeater controller (an S-COM) to the MICOR station By Bob Hoffman N3CVL (off-site link)

Another connection of a repeater controller (an S-COM) to the MICOR Unified Chassis Station However this technique will work with any controller that can accept active low COR and PL decode signals and output an active low PTT signal (i.e. one that goes to ground). By Joel Huntley WA1ZYX (off-site link)

Modification of the older Station Control Module TLN4635B (Click here for parts layout) When using a repeater controller. By Kevin Custer W3KKC

Modification of the newer Station Control Module TLN5970A (or later) When using a repeater controller. By Kevin Custer W3KKC

Modifying the TRN4662 Squelch Gate Module as an interface to an external controller By Richard Reese WA8DBW (off-site link)

Modifying the TRN4662 Squelch Gate Module for better operation as a repeater controller By M. Scott Zimmerman N3XCC

Conversion of the MICOR® TRN6006 series Station Audio & Squelch board For better audio muting By Kevin Custer W3KKC

Using a converted TLN4310 MICOR® mobile audio & squelch board in a base/repeater station By Kevin Custer W3KKC

Conversion of the MICOR Compa-Station Receiver Interconnect Board By Kevin Custer W3KKC

Documentation on the TLN5167A Intercom, TLN5900 and TLN5993 Station Metering Kit, and TLN1859 and TLN1887 Metering and Intercom Kits Donated by Eric Lemmon WB6FLY

Converting the Unified Chassis Station to 12vDC only 229 KB PDF
This three-page PDF writeup got separated from it's email and I do not know whom to credit... please drop WA6ILQ an email and I'll fix that.
The standard Micor station power supplies deliver unregulated +V to the PA deck, regulated +12vDC and +9.6vDC to the unified chassis (the control shelf, exciter and the receiver). In some cases you want to power the station from an existing +12vDC source. This writeup shows how to modify the unified chassis to generate its own 9.6vDC. Non-unified stations can do this mod separately to the control shelf, the exciter chassis and to the receiver chassis.

Parts layout of the TLN4635 Station Control Module: original (180kb) enhanced (616kb) enhanced & rotated (616kb) Provided by Eric Lemmon WB6FLY
The "enhanced" file has a bit of contrast tweaking by WA6ILQ. The rotated file is properly aligned for printing.

BTW, if you need replacement or additional card guides for the MICOR station card cage they are part number 45B83914G01 at about $2 each

Station Power Supplies:

Full manual for the TPN1095A, TPN1096A, and TPN1102A station power supplies 5.8mb PDF file.
This was a high-resolution scan provided by Don Kovalchik, W8DPK; it was subsequently reduced in size.

Schematic of the TPN1105 and TPN1106 station power supply 128kb
The TPN1105A can be wired for either 120v or 240vAC, but the TPN1106A is 120vAC only. The manual for either one is 68-81104E92. This supply has the automatic power fail changeover to battery feature.

Schematic of the TPN1110 station ferro-resonant power supply 144kb
This schematic is from manual 68P81020E44-N and covers both the TPN1110A and TPN1110B models that provide unregulated 13.8v at 25 amps for the PA deck plus 12v and 9.6 volts regulated.

Schematic of the TPN1151 and TPN1152 station power supplies 73kb
The TPN1151A can be wired for 120 or 240vAC, but the TPN1152A is 120vAC only. This is a fully linear supply with separate linear regulators for the +9.6v, low and high current 12v voltages.

Low Band MICOR Station:
The low-band Micors came in 4 ranges: 25-30 (very, very rare), 30-36, 36-42, and 42-50 MHz. The four articles below are all oriented to the 42-50 MHz radios. If anyone would like to do a 30-36 to 10 meters conversion article please let us know.
The low band receiver is a TLB585nA or B, and the IF is 5.26 MHz, or 5.36 MHz on special order.
The "n" was 1 for 25-30 MHz, 2 was 30-36 MHz, 3 was 36-42 MHz, and 4 was 42-50 MHz.
The 25-30 receiver used a x2 multiplier and high side injection, the 30-36 and 36-42 receivers used x3 and high side injection, and the 42-50 receiver used x3 and low side injection.

Conversion of the MICOR Low-band receiver to the 6 meter amateur band By Kevin Custer W3KKC

Conversion of the MICOR Low-band exciter to the 6 meter ham band By Kevin Custer W3KKC

Another conversion site for MICOR Low-band to 6M Ham Band Offsite link to KB6MIP's site

Yet another conversion article for the MICOR Low-band to 6M Ham Band With photos, circles and arrows, and paragraphs on the back... by Robert W. Meister WA1MIK

High Band MICOR Station: (220MHz mods are in the 220 section below)
The high band receiver is a TLD827nA or B, and the IF is 11.7 MHz, or 11.8 MHz on special order. "n" is 1 for 132-142 MHz, 2 is 142-150.8 MHz, 3 is 150.8 to 162 MHz, and 4 is 162-174 MHz.
All high band receivers used a x9 multiplier. The 132-142 and 142-150.8 receivers used high side injection, the 150.8-162 and 162-174 receivers used low side injection.

Comprehensive Description of the MICOR "Sensitron" Hi-band Receiver By Kevin Custer W3KKC

Conversion of the MICOR "Sensitron" High-band Receiver to the 2m Ham Band By Kevin Custer W3KKC

Now available: 132-150.8MHz helical resonator coils Get a real 2 meter front-end for your MICOR receiver! By Kevin Custer W3KKC

Modification of the MICOR Exciter By Kevin Custer W3KKC

VHF MICOR PM to FM Exciter Modification Convert your PM exciter to True FM! By Kevin Custer W3KKC

VHF MICOR tuning instructions By Kevin Custer W3KKC

Retuning the VHF MICOR Bandpass Filter By Kevin Custer W3KKC

A Conversion of a high band MICOR Intermittent Station to a Repeater By Lawrence Glaister VE7IT

Documentation on the high band MICOR Preamp model TLD8421A, TLD8421B, TLD8422A or TLD8422B Donated by Eric Lemmon WB6FLY
Note that if you need a preamp and can't find one that AngleLinear sells a very nice drop-in preamp, and a mounting bracket is available.

Conversion of the MICOR High-band Factory Preamp To The 2m Ham band By Kevin Custer W3KKC

MICOR High Band Service Sheet Pg 1 This is Moto manual 68P81101E02-M Page 1. Donated by Eric Lemmon WB6FLY
MICOR High Band Service Sheet Pg 2 This is page 2 of the above.

Micor DVP VHF Station Manual 6881036E40-B (no longer available): Complete manual (41.8 MB)
In sections: Pages 1-122 (16.8 MB) Pages 123-165 (12.3 MB) Pages 166-187 (12.8 MB)

UHF MICOR Station:
The UHF receiver is a TRE120nA or B, and the IF is 11.7 MHz, or 11.8 MHz if needed to avoid mixes.
"n" is 1 for 406-420 MHz, 2 is 420-450 MHz, 3 is 450-470 MHz, 4 is 470-494 MHz and 5 is 494-512 MHz.
All UHF receivers used a x24 multiplier. The high versus low injection decision was dependent on several parameters.

Repair notes and schematic for the UHF Station Tripler By Bill Hance KD7CWA

Conversion of the UHF "Sensitron" Receiver to 440MHz Ham Band By Kevin Custer W3KKC

Additional Info and Images about the above conversion for 435-450 MHz By Robert Meister WA1MIK

Documentation on the UHF preamp model TLE8191A and TLE8192A 531 Kb PDF 6 page file from Eric Lemmon WB6FLY
Note that if you need a preamp and can't find one that AngleLinear sells a very nice drop-in preamp, and a mounting bracket is available.

Modification of the UHF Exciter By Kevin Custer W3KKC

Tuning the UHF Station BPF's and Circulator (antenna network) By Kevin Custer W3KKC

Information relevant to MICOR Mobiles being converted to Repeater or Link duty:
Notes:
1) The MICOR mobile chassis has a heat sink rated at only 35 watts - yes, that fact is in the MICOR mobile manual. Therefore radios higher than 45 watts are best left in mobile service.
2) The VHF Micor transmitter power amplifier stages use PNP transistors where the UHF radio uses NPN in the same area. Be careful when you do a rebuild that you have the right parts !!!
3) The normal mounting of a Micor mobile has the circuit boards upside down in the top of the case facing downward. As such the control connector pinout is not what you would expect. Here is a drawing of the pinout viewed from outside the radio, looking at the front.

Generic Mobile Information:

Front casting modification for a second antenna connector By Kevin Custer W3KKC

Duplex modification of MICOR mobile audio & squelch board By Kevin Custer W3KKC

MICOR Muteboard®, muting audio filter amplifier By Kevin Custer W3KKC

Modification of the MICOR PL Encoder In some situations you want to disable the reverse-burst capability. By Kevin Custer W3KKC

COS Logic Level Inverter For making positive logic cos from the Audio-Squelch board. By Kevin Custer W3KKC

Low-band MICOR Mobile: The low-band Micors came in 4 ranges: 25-30 (very, very rare), 30-36, 36-42, and 42-50 MHz. The three articles below are all oriented to the 42-50 MHz radios. If anyone would like to do a 30-36 to 10 meters conversion article please let us know.
The low band receiver is a TLB585nA or B, and the IF is 5.26 MHz, or 5.36 MHz on special order.
The "n" was 1 for 25-30 MHz, 2 was 30-36 MHz, 3 was 36-42 MHz, and 4 was 42-50 MHz.
The 25-30 receiver used a x2 multiplier and high side injection, the 30-36 and 36-42 receivers used x3 and high side injection, and the 42-50 receiver used x3 and low side injection.

Conversion of the MICOR Low-band receiver to the 6 meter ham band By Kevin Custer W3KKC

Conversion of the MICOR Low-band exciter to the 6 meter ham band By Kevin Custer W3KKC

Another conversion site for MICOR Low-band to 6M Ham Band Offsite link to KB6MIP's site

High-band MICOR Mobile: (220MHz mods are in the 220 section below)
The high band receiver is a TLD827nA or B, and the IF is 11.7 MHz, or 11.8 MHz on special order. "n" is 1 for 132-142 MHz, 2 is 142-150.8 MHz, 3 is 150.8 to 162 MHz, and 4 is 162-174 MHz.
All high band receivers used a x9 multiplier. The 132-142 and 142-150.8 receivers used high side injection, the 150.8-162 and 162-174 receivers used low side injection.

Duplex conversion of a standard VHF mobile to repeater   By Kevin Custer W3KKC

Duplex conversion of Railroad VHF mobile to repeater By Kevin Custer W3KKC

Duplex conversion of a VHF mobile to a repeater station By Jim Reese WD5IYT

Duplex Conversion of the mobile antenna switch   By Kevin Custer W3KKC

VHF Exciter Models An explanation of the 3 different exciters common to the VHF radio. By Kevin Custer W3KKC

VHF PM to FM Exciter Modification Convert your PM exciter to True FM! By Kevin Custer W3KKC

VHF board model number frequency ranges An explanation of the board numbers on a VHF MICOR. By Kevin Custer W3KKC

132-150.8MHz helical resonator coils for the MICOR Get the right coils for your 2 meter front-end. By Kevin Custer W3KKC

Comprehensive Description of the "Sensitron" Hi-band Receiver By Kevin Custer W3KKC

Conversion of the "Sensitron" High-band Receiver to Ham Band By Kevin Custer W3KKC

Modification of the VHF Exciter By Kevin Custer W3KKC

Retuning the VHF Bandpass Filter By Kevin Custer W3KKC

VHF tuning instructions By Kevin Custer W3KKC

Documentation on the high band preamp model TLD8421B and TLD8422B Donated by Eric Lemmon WB6FLY
Note that if you need a preamp and can't find one that AngleLinear sells a very nice drop-in preamp, and a mounting bracket is available.

Conversion of the High-band Preamp To Ham Band   By Kevin Custer W3KKC

Documentation on the 45 watt VHF PA deck 3mb PDF 15 page file from Eric Lemmon WB6FLY

High Band Service Sheet Pg 1 This is Moto manual 68P81101E02-M Page 1. Donated by Eric Lemmon WB6FLY
High Band Service Sheet Pg 2 This is page 2 of the above.

UHF MICOR Mobile:
The UHF receiver is a TRE120nA or B, and the IF is 11.7 MHz, or 11.8 MHz if needed to avoid mixes.
"n" is 1 for 406-420 MHz, 2 is 420-450 MHz, 3 is 450-470 MHz, 4 is 470-494 MHz and 5 is 494-512 MHz.
All UHF receivers used a x24 multiplier. The high versus low injection decision was dependent on several parameters.

A Technical Explanation of the MICOR UHF Mobile Radio Set A walkthrough of how only one channel element / crystal can work for receive, transmit repeat and transmit simplex. By Kevin Custer W3KKC

Motorola's own technical description of the UHF MICOR Mobile Radio Section 4, all 33 pages of it, from the official manual. By Kevin Custer W3KKC

Duplex conversion of MICOR® UHF mobile to repeater station By Jim Reese WD5IYT

Information on the UHF Mobile Low Level Amplifier (LLA) How to increase the life expectancy By Jeff DePolo WN3A

Conversion of the MICOR "Sensitron" UHF Receiver to the UHF ham band By Kevin Custer W3KKC

Modification of the MICOR UHF Exciter The standard Motorola microphone has a preamp inside the cartridge, and the radio supplies DC voltage on the mic audio lead to run it. This writeup shows how to get rid of it. By Kevin Custer W3KKC

Documentation on the UHF preamp model TLE8191A and TLE8192A 531 Kb PDF 6 page file from Eric Lemmon WB6FLY
Note that if you need a preamp and can't find one that AngleLinear sells a very nice drop-in preamp, and a mounting bracket is available.

Emergency Medical Systems Duplex / Repeater UHF Mobile Radio manual supplement PDF file courtesy of K9ROD
This is the no-longer-available manual supplement for the full-duplex dual-receiver repeating ambulance radio model Q2033 and Q1853. Note that you need the regular UHF mobile manual 68-81015E70 to go along with it.
Note this is a 16.6 MB file - you better have broadband or plan on an all-night download...
Just right-click and "Save As".

Custom Modifications, Conversions and Parts Supplier for MICOR® Mobiles and Stations:

MICOR Repeater Conversions from Repeater-Builder
Custom Conversions by Kevin Custer and Scott Zimmerman from a certified Motorola Service Shop (MSS)

Channel Element Info

MICOR channel element schematic diagrams and other information (with photos) by Scott Zimmerman - N3XCC

What's inside the K1003 channel element (with photos and schematic) by Robert W. Meister - WA1MIK

220 MHz. Modifications for the MICOR High-Band Radio

Comprehensive Conversion of the MICOR High-Band Receiver to 222 MHz By Kevin Custer W3KKC (new method)

Comprehensive Conversion of the MICOR High-Band Exciter to 222 MHz By Kevin Custer and Scott Zimmerman (new method)

Conversion of the MICOR VHF exciter Band-Pass Filter to 220MHz By Lee Woldanski VE7FET

MICOR 222 Mc. Modifications Considerations from SEITS

Packet Modifications for the MICOR:

9600 baud modifications for the UHF MICOR By Verne Buland

Other information relating to the Motorola MICOR:

Other Motorola information at WA8DBW's web site By Richard Reese WA8DBW offsite link

Scanned Images:         Most are oriented for printing, not viewing...

MICOR palm microphone schematic 21k

MICOR mobile radio interconnect board relay area 118k

MICOR Mobile Audio & Squelch Board layout 157k

MICOR Audio & Squelch Board schematic 166k

MICOR High-Band Exciter Board layout 157k

Picture of the MICOR mobile control head back side 38kb (vertical for printing) Horizontal (for viewing) 38kb

MICOR mobile control head schematic 261k
The wide-spaced UHF mobile has both channel select and repeat-offset on/off lines.   A common modification on these radios in amateur use is to take the repeat offset on/off line and connect it to a spare lead in the cable rather than into the channel element selecting diode matrix.   A mini-toggle switch is frequently installed in the control head just for repeat / simplex selection.   The Syntor series of radios (they can be though of as synthesized MICORs) had a optional faceplate for the clamshell head that was made just for this purpose (the switch is labeled "R" and "S").   This faceplate will fit the MICOR head perfectly.

A second common modification is to rectify the design oversight in the MICOR "clamshell" control head: there is no receiver PL control switch - a "Monitor" switch, if you will.   The designer expected you to use a microphone clip with a switch in it... with the microphone in the clip the PL was on, out of the clip you are in carrier squelch (monitor) mode.   One solution to this problem is to cut the trace on the control head PC board between J1101 pins 4 and 15 (not easy to do, but can be done with patient work with an X-Acto knife after using solder-wick to remove the excess solder) and jumper the cut with a SPST toggle switch. This new switch when shorted will enable the PL decoder (by cutting the trace and bridging the cut with the switch it is placed in series with the microswitch in the hang-up box).

Engineering Notes provided by various reliable sources:

Subject - MICOR High-Band Exciter transmit frequency spacing.
Bob Swoger, K9WVY points out that the Motorola manual is in error when it states the High Band MICOR Mobile has a transmitter spread of only 1.5 MHz. That is what the marketing group told the sales force. Actually, the transmitter spread is 3 MHz on the standard production radio. The designer of the first MICOR HB exciter was Jim Cox, a non-ham and laid off shortly after the MICOR shipped in 1970 due to the fact that he was the oldest and losing his hair. That first exciter board was single sided and had grounding problems due to not enough copper foil. This was a problem with the early PC board layout people. They wanted to start with a non copper clad board and add copper. Engineers wanted them to start with a double sided copper clad board and remove copper. Jim's board indeed was only 1.5 MHz wide. Soon after another engineer named Don Nicklos (spelling?) made a double sided board that solved a lot of problems with proper grounding. Don told me the new board could easily do 2 MHz and more. I checked it out and found it could do 3 MHz. Marketing was dead set against changing the published spec.

Then the State of Wisconsin put out a request for bid for high power high band radios with a transmitter spread of 2 MHz. GE could do this with their standard MASTRII. The MICOR as advertised would require the Wide Spaced Exciter option which would cost $150 more than the GE MASTR II as I recall. My boss at that time had heard that I was running a MICOR mobile on 2 meters without a wide spaced exciter option and called me into the office. He asked me to prove the standard product was as wide as I claimed it was by testing the radio between –40C to +70C. I found I could get more that 3 MHz transmitter separation if I tuned the exciter 1 MHz above the lowest frequency.

We beat GE by $5 per box and won the contract. So, please change the web page to indicate the exciter is 3 MHz wide if it is center tuned 1 MHz above the lowest frequency. -- Bob

About Bob Swoger My name is Robert E. Swoger, K9WVY. I was at Motorola from 1965 until I retired in 2002. I was in the original MICOR Mobile design team from 1969 on. Not only did I design new MICOR radios, I later designed and FIXED designs of standard and custom MICOR Mobile and Bases. When I wrapped it up I was in the design team of Saber, Cosmos and Spectra radios.

Several of the correction and additions to this site have been made by Bob Swoger, thanks Bob!
Kevin Custer and the Repeater Builder Group.

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Motorola® and MICOR® are registered trademarks of Motorola Inc.
Image(s) used with permission of Motorola Inc.

This web page, this web site, the information presented in and on its pages and in these modifications and conversions is © Copyrighted 1995 and (date of last update) by Kevin Custer W3KKC and multiple originating authors. All Rights Reserved, including that of paper and web publication elsewhere.

	Base and Repeater Control and Applications Manual 68-81025E60 (non-RF information common to all stations)
	Compa-Station Base & Repeater Radio 25-50 MHz 100 watts 68-81013E60 (Low Band)
	Compa-Station Base Radio Remote Control 132-174 MHz 68-81013E65 (High Band)
	Base and Repeater Station 450-470 or 470-512MHz 68-81025E50 (UHF)
	Community Repeater Station Supplement 68-81025E55, This is a supplement to the standard Control and Applications manual. You will need this supplement if you have the "Community Repeater" backplane and / or modules. There are several differences between a standard repeater configuration and the community repeater configuration (even if you are going to run only one PL tone, or even in carrier squelch mode)
	Mobile UHF (standard and wide spaced): 68P81015E70
	Mobile high band manual: 68P81008E40 Mobile high band wide-spaced supplement: 68P81014E15 (see note below)
	Mobile Low Band manual: 68P81008E35

	The MICOR Squelch Explanation of the MICOR® Bi-Level Squelch. By Kevin Custer W3KKC
	MICOR® based squelch circuit A SEITS article
	Explanation of Reverse Burst & "And" Squelch By Kevin Custer W3KKC
	Pre-emphasis, de-emphasis, clipping, and audio quality in the MICOR By Paul Sexauer K3VIX
	MICOR Muteboard®, muting audio filter amplifier By Kevin Custer W3KKC
	Modification of the MICOR PL Encoder In some situations you want to disable the reverse-burst capability By Kevin Custer W3KKC
	COS Logic Level Inverter A simple circuit to make positive logic COS from the audio-squelch board for those controllers that require it By Kevin Custer W3KKC
	MICOR® discriminator buffer amplifier Great for NHRC, MCC, and other newer style controllers that mute and have de-emphasis built in
	MICOR® PL® filter By Kevin Custer W3KKC
	An "S-Meter" for the MICOR Receiver While this circuit was originally developed to allow a repeater receiver to drive an analog input of an ACC repeater controller there is no reason that it couldn't drive a different brand of repeater controller or even a meter...
	Schematic of the TLN-4310B-2 mobile audio-squelch board scanned from the mobile manual This is oriented horizontally, for viewing on your screen.
	Schematic of the TLN-4310B-2 mobile audio-squelch board scanned from the mobile manual This is oriented vertically, for printing (you will probably want to print it on legal paper, as it is an extended length diagram. If you are going to do any bench work, I'd suggest printing it on 11x17 paper.
	Information on MICOR Channel Elements By M. Scott Zimmerman

	Comprehensive conversion of the MICOR® Compa-Station base/repeater station By Kevin Custer W3KKC
	Synthesize your MICOR Station By Greg Carttar (ex-WAØLCZ) of 3rd St. R & D Production Services (offsite link)
	Modification of the MICOR PL Encoder In some situations you want to disable the reverse-burst capability By Kevin Custer W3KKC
	Notes on how to simply connect a generic repeater controller to a MICOR station By M. Scott Zimmerman N3XCC
	An IDer for the MICOR Repeater Shelf By Jerry Matthews WAØUZI Useful to the commercial repeaters as the amateur radio repeater controllers have built-in ID'ers. While an IDer is not required for GMRS, it's a good idea and this article is relevant there as well.
	One method of connection of a repeater controller (an S-COM) to the MICOR station By Bob Hoffman N3CVL (off-site link)
	Another connection of a repeater controller (an S-COM) to the MICOR Unified Chassis Station However this technique will work with any controller that can accept active low COR and PL decode signals and output an active low PTT signal (i.e. one that goes to ground). By Joel Huntley WA1ZYX (off-site link)
	Modification of the older Station Control Module TLN4635B (Click here for parts layout) When using a repeater controller. By Kevin Custer W3KKC
	Modification of the newer Station Control Module TLN5970A (or later) When using a repeater controller. By Kevin Custer W3KKC
	Modifying the TRN4662 Squelch Gate Module as an interface to an external controller By Richard Reese WA8DBW (off-site link)
	Modifying the TRN4662 Squelch Gate Module for better operation as a repeater controller By M. Scott Zimmerman N3XCC
	Conversion of the MICOR® TRN6006 series Station Audio & Squelch board For better audio muting By Kevin Custer W3KKC
	Using a converted TLN4310 MICOR® mobile audio & squelch board in a base/repeater station By Kevin Custer W3KKC
	Conversion of the MICOR Compa-Station Receiver Interconnect Board By Kevin Custer W3KKC
	Documentation on the TLN5167A Intercom, TLN5900 and TLN5993 Station Metering Kit, and TLN1859 and TLN1887 Metering and Intercom Kits Donated by Eric Lemmon WB6FLY
	Converting the Unified Chassis Station to 12vDC only 229 KB PDF This three-page PDF writeup got separated from it's email and I do not know whom to credit... please drop WA6ILQ an email and I'll fix that. The standard Micor station power supplies deliver unregulated +V to the PA deck, regulated +12vDC and +9.6vDC to the unified chassis (the control shelf, exciter and the receiver). In some cases you want to power the station from an existing +12vDC source. This writeup shows how to modify the unified chassis to generate its own 9.6vDC. Non-unified stations can do this mod separately to the control shelf, the exciter chassis and to the receiver chassis.

	Parts layout of the TLN4635 Station Control Module: original (180kb) enhanced (616kb) enhanced & rotated (616kb) Provided by Eric Lemmon WB6FLY The "enhanced" file has a bit of contrast tweaking by WA6ILQ. The rotated file is properly aligned for printing.
	BTW, if you need replacement or additional card guides for the MICOR station card cage they are part number 45B83914G01 at about $2 each

	Full manual for the TPN1095A, TPN1096A, and TPN1102A station power supplies 5.8mb PDF file. This was a high-resolution scan provided by Don Kovalchik, W8DPK; it was subsequently reduced in size.
	Schematic of the TPN1105 and TPN1106 station power supply 128kb The TPN1105A can be wired for either 120v or 240vAC, but the TPN1106A is 120vAC only. The manual for either one is 68-81104E92. This supply has the automatic power fail changeover to battery feature.
	Schematic of the TPN1110 station ferro-resonant power supply 144kb This schematic is from manual 68P81020E44-N and covers both the TPN1110A and TPN1110B models that provide unregulated 13.8v at 25 amps for the PA deck plus 12v and 9.6 volts regulated.
	Schematic of the TPN1151 and TPN1152 station power supplies 73kb The TPN1151A can be wired for 120 or 240vAC, but the TPN1152A is 120vAC only. This is a fully linear supply with separate linear regulators for the +9.6v, low and high current 12v voltages.

	Conversion of the MICOR Low-band receiver to the 6 meter amateur band By Kevin Custer W3KKC
	Conversion of the MICOR Low-band exciter to the 6 meter ham band By Kevin Custer W3KKC
	Another conversion site for MICOR Low-band to 6M Ham Band Offsite link to KB6MIP's site
	Yet another conversion article for the MICOR Low-band to 6M Ham Band With photos, circles and arrows, and paragraphs on the back... by Robert W. Meister WA1MIK

	Comprehensive Description of the MICOR "Sensitron" Hi-band Receiver By Kevin Custer W3KKC
	Conversion of the MICOR "Sensitron" High-band Receiver to the 2m Ham Band By Kevin Custer W3KKC
	Now available: 132-150.8MHz helical resonator coils Get a real 2 meter front-end for your MICOR receiver! By Kevin Custer W3KKC
	Modification of the MICOR Exciter By Kevin Custer W3KKC
	VHF MICOR PM to FM Exciter Modification Convert your PM exciter to True FM! By Kevin Custer W3KKC
	VHF MICOR tuning instructions By Kevin Custer W3KKC
	Retuning the VHF MICOR Bandpass Filter By Kevin Custer W3KKC
	A Conversion of a high band MICOR Intermittent Station to a Repeater By Lawrence Glaister VE7IT
	Documentation on the high band MICOR Preamp model TLD8421A, TLD8421B, TLD8422A or TLD8422B Donated by Eric Lemmon WB6FLY Note that if you need a preamp and can't find one that AngleLinear sells a very nice drop-in preamp, and a mounting bracket is available.
	Conversion of the MICOR High-band Factory Preamp To The 2m Ham band By Kevin Custer W3KKC
	MICOR High Band Service Sheet Pg 1 This is Moto manual 68P81101E02-M Page 1. Donated by Eric Lemmon WB6FLY MICOR High Band Service Sheet Pg 2 This is page 2 of the above.
	Micor DVP VHF Station Manual 6881036E40-B (no longer available): Complete manual (41.8 MB) In sections: Pages 1-122 (16.8 MB) Pages 123-165 (12.3 MB) Pages 166-187 (12.8 MB)

	Repair notes and schematic for the UHF Station Tripler By Bill Hance KD7CWA
	Conversion of the UHF "Sensitron" Receiver to 440MHz Ham Band By Kevin Custer W3KKC
	Additional Info and Images about the above conversion for 435-450 MHz By Robert Meister WA1MIK
	Documentation on the UHF preamp model TLE8191A and TLE8192A 531 Kb PDF 6 page file from Eric Lemmon WB6FLY Note that if you need a preamp and can't find one that AngleLinear sells a very nice drop-in preamp, and a mounting bracket is available.
	Modification of the UHF Exciter By Kevin Custer W3KKC
	Tuning the UHF Station BPF's and Circulator (antenna network) By Kevin Custer W3KKC

	Front casting modification for a second antenna connector By Kevin Custer W3KKC
	Duplex modification of MICOR mobile audio & squelch board By Kevin Custer W3KKC
	MICOR Muteboard®, muting audio filter amplifier By Kevin Custer W3KKC
	Modification of the MICOR PL Encoder In some situations you want to disable the reverse-burst capability. By Kevin Custer W3KKC
	COS Logic Level Inverter For making positive logic cos from the Audio-Squelch board. By Kevin Custer W3KKC

	Duplex conversion of a standard VHF mobile to repeater By Kevin Custer W3KKC
	Duplex conversion of Railroad VHF mobile to repeater By Kevin Custer W3KKC
	Duplex conversion of a VHF mobile to a repeater station By Jim Reese WD5IYT
	Duplex Conversion of the mobile antenna switch By Kevin Custer W3KKC
	VHF Exciter Models An explanation of the 3 different exciters common to the VHF radio. By Kevin Custer W3KKC
	VHF PM to FM Exciter Modification Convert your PM exciter to True FM! By Kevin Custer W3KKC
	VHF board model number frequency ranges An explanation of the board numbers on a VHF MICOR. By Kevin Custer W3KKC
	132-150.8MHz helical resonator coils for the MICOR Get the right coils for your 2 meter front-end. By Kevin Custer W3KKC
	Comprehensive Description of the "Sensitron" Hi-band Receiver By Kevin Custer W3KKC
	Conversion of the "Sensitron" High-band Receiver to Ham Band By Kevin Custer W3KKC
	Modification of the VHF Exciter By Kevin Custer W3KKC
	Retuning the VHF Bandpass Filter By Kevin Custer W3KKC
	VHF tuning instructions By Kevin Custer W3KKC
	Documentation on the high band preamp model TLD8421B and TLD8422B Donated by Eric Lemmon WB6FLY Note that if you need a preamp and can't find one that AngleLinear sells a very nice drop-in preamp, and a mounting bracket is available.
	Conversion of the High-band Preamp To Ham Band By Kevin Custer W3KKC
	Documentation on the 45 watt VHF PA deck 3mb PDF 15 page file from Eric Lemmon WB6FLY
	High Band Service Sheet Pg 1 This is Moto manual 68P81101E02-M Page 1. Donated by Eric Lemmon WB6FLY High Band Service Sheet Pg 2 This is page 2 of the above.

	A Technical Explanation of the MICOR UHF Mobile Radio Set A walkthrough of how only one channel element / crystal can work for receive, transmit repeat and transmit simplex. By Kevin Custer W3KKC
	Motorola's own technical description of the UHF MICOR Mobile Radio Section 4, all 33 pages of it, from the official manual. By Kevin Custer W3KKC
	Duplex conversion of MICOR® UHF mobile to repeater station By Jim Reese WD5IYT
	Information on the UHF Mobile Low Level Amplifier (LLA) How to increase the life expectancy By Jeff DePolo WN3A
	Conversion of the MICOR "Sensitron" UHF Receiver to the UHF ham band By Kevin Custer W3KKC
	Modification of the MICOR UHF Exciter The standard Motorola microphone has a preamp inside the cartridge, and the radio supplies DC voltage on the mic audio lead to run it. This writeup shows how to get rid of it. By Kevin Custer W3KKC
	Documentation on the UHF preamp model TLE8191A and TLE8192A 531 Kb PDF 6 page file from Eric Lemmon WB6FLY Note that if you need a preamp and can't find one that AngleLinear sells a very nice drop-in preamp, and a mounting bracket is available.
	Emergency Medical Systems Duplex / Repeater UHF Mobile Radio manual supplement PDF file courtesy of K9ROD This is the no-longer-available manual supplement for the full-duplex dual-receiver repeating ambulance radio model Q2033 and Q1853. Note that you need the regular UHF mobile manual 68-81015E70 to go along with it. Note this is a 16.6 MB file - you better have broadband or plan on an all-night download... Just right-click and "Save As".

	MICOR channel element schematic diagrams and other information (with photos) by Scott Zimmerman - N3XCC
	What's inside the K1003 channel element (with photos and schematic) by Robert W. Meister - WA1MIK

	Comprehensive Conversion of the MICOR High-Band Receiver to 222 MHz By Kevin Custer W3KKC (new method)
	Comprehensive Conversion of the MICOR High-Band Exciter to 222 MHz By Kevin Custer and Scott Zimmerman (new method)
	Conversion of the MICOR VHF exciter Band-Pass Filter to 220MHz By Lee Woldanski VE7FET
	MICOR 222 Mc. Modifications Considerations from SEITS

	MICOR palm microphone schematic 21k
	MICOR mobile radio interconnect board relay area 118k
	MICOR Mobile Audio & Squelch Board layout 157k
	MICOR Audio & Squelch Board schematic 166k
	MICOR High-Band Exciter Board layout 157k
	Picture of the MICOR mobile control head back side 38kb (vertical for printing) Horizontal (for viewing) 38kb
	MICOR mobile control head schematic 261k The wide-spaced UHF mobile has both channel select and repeat-offset on/off lines. A common modification on these radios in amateur use is to take the repeat offset on/off line and connect it to a spare lead in the cable rather than into the channel element selecting diode matrix. A mini-toggle switch is frequently installed in the control head just for repeat / simplex selection. The Syntor series of radios (they can be though of as synthesized MICORs) had a optional faceplate for the clamshell head that was made just for this purpose (the switch is labeled "R" and "S"). This faceplate will fit the MICOR head perfectly. A second common modification is to rectify the design oversight in the MICOR "clamshell" control head: there is no receiver PL control switch - a "Monitor" switch, if you will. The designer expected you to use a microphone clip with a switch in it... with the microphone in the clip the PL was on, out of the clip you are in carrier squelch (monitor) mode. One solution to this problem is to cut the trace on the control head PC board between J1101 pins 4 and 15 (not easy to do, but can be done with patient work with an X-Acto knife after using solder-wick to remove the excess solder) and jumper the cut with a SPST toggle switch. This new switch when shorted will enable the PL decoder (by cutting the trace and bridging the cut with the switch it is placed in series with the microswitch in the hang-up box).