Attention Ebay buyers and sellers: If you are buying or selling a MaxTrac, Radius mobile, or GM300 you need to read the warning on this page.

Any Motorola prices mentioned on this page (or on any page at this web site) should be taken only as a rough guideline.   Motorola adjusts prices quarterly, and offers one set of prices to their dealers/service shops (the so called "NSO" Pricing ("National Service Organization")), another to "self-maintaining" fleet customers (i.e. those that have their own radio shops... cities, counties, police departments, fire departments, etc) and a third on their telephone order desk (i.e. retail sales to the public).   Prices are changed quarterly, so use the mentioned prices only as a rough indication.   If you encounter a large price change on anything where we've mentioned a price we'd appreciate an emailed update.

Radio Modification and Descriptive Articles:

Caution: A lot of the information in the articles below is valid only for MaxTracs and MaxTrac-based Radius radios (the Radius mobiles that have the letters LRA in the middle of the model number). The MaxTracs came first, then when Motorola needed radios to sell as Radius models (i.e. retail sales products) they changed the label and the firmware. There are some differences, but there is a lot of commonality between the hardware (the circuit boards, etc) inside the MaxTrac and Radius LRA series mobiles.

The later GM300 series (which includes the Radius M10, M120 and M130 radios) look a lot like the MaxTrac and Radius LRA series, have similar specifications and physical construction, but are actually quite different internally. The GM300 series do not respond well to being blanked by the MaxTrac Lab RSS. There is no Radius or GM300 series Lab RSS floating around (yet) so unsuspecting experimenters can turn one of these radios into an expensive brick if not careful. See the GM300 article below for more details.

You should read the first article below before any of the other articles here.

	Introductory Information on the MaxTrac, Radius and GM300 series radios, the DeskTrac station, and the GR300, GR400, GR500, GR1225, R1225 and RKR1225 series repeaters   Compiled by Mike Morris WA6ILQ An introduction to the Motorola radios covered by this section, with background, history, some model-specific information, photos, and lots of miscellaneous tidbits such as mic jack or antenna connector replacement.
	An Introduction to the MaxTrac or Radius M100 / M214 / M216 Firmware, Logic Boards and RF Boards   By Neil Johnson WBØEMU What your radio can do depends a lot on what version firmware you have in which logic board mated to which RF board.
	MaxTrac Logic Board Jumpers and Connectors   By Robert Meister, WA1MIK Locations and explanations of the three-pin jumpers on MaxTrac and Radius logic boards, as well as the signals on the three multi-pin connectors.
	Information about the GM300-series radios   By Robert Meister, WA1MIK Specs, board numbers, accessory plugs, how they differ from MaxTracs.
	Narrow-band conversion kits for the GM300-series radios   By Robert Meister, WA1MIK Transcribed from the official document that can be found elsewhere on this site.
	Adding additional channels to the GM300   By Thomas M. Mayse, KN5S If your GM300 has the expanded logic board it can have as many as 40 channels. Moto learned their lesson on the 32-channel MaxTrac and artificially limited GM300 to 16 channels so that they could force anyone needing more than 16 into a Spectra. Tom walks you through a step-by-step procedure.
	MaxTrac VHF, UHF, and 800 MHz radio models   By the Repeater-Builder Staff Information taken directly from the "No Longer Available" detailed service manual.
	MaxTrac 900 MHz radio models   By Repeater-Builder Staff Information taken directly from the "No Longer Available" service manuals.
	Radius M100, M206, M208, M214, M216 radio models and board info  Compiled by Robert W. Meister, WA1MIK Information extracted from the Radius Service Manual (of course NLA).
	The MaxTrac Parts Catalog   16 page, 2.2MB PDF file donated by A. Nony Mous
	Another MaxTrac Parts Catalog   200KB PDF file
	A Radius M10 / M110 / M120 Parts Catalog   200KB PDF file
	A Radius M208 / M216 Parts Catalog   200KB PDF file
	The Radius GM300 Parts Catalog   200KB PDF file donated by A. Nony Mous
	A reproduction of the MaxTrac Performance Specifications   20KB PDF file donated by A. Nony Mous
	Upgrading a MaxTrac or Radius M100 / M214 / M216 to 32 channels - with photos     By Scott Lichtsinn KBØNLY.   A step-by-step procedure that will upgrade any MaxTrac (except the 2-channel ones) to 16 or 32 channels (depending on which logic board you have), with options like scan.
	Additional Notes on MaxTrac or Radius M100 / M214 / M216 Logic Boards   By Scott Lichtsinn KBØNLY This article goes with the "Upgrading" article. It has additional notes including a procedure for converting a trunking logic board to conventional.
	Moving a 449-470 MHz MaxTrac to cover the 440-450 MHz Amateur band - with photos   By Scott Lichtsinn KBØNLY A step-by-step procedure that makes a UHF MaxTrac a lot more useful on 440-450 MHz.
	Repeater controller interfacing - with photos     By Scott Lichtsinn KBØNLY With information on connections to radios with both 16-pin and 5-pin logic boards.
	Simple Repeater Interfacing for MaxTrac / Radius / GM300 Radios   By Robert Meister, WA1MIK A very simple procedure with all the details needed to interface these radios to most repeater controllers. This is a companion article to the ones above and below.
	The Definitive Guide to the 16 pin MaxTrac and Radius Option Connector   By Neil Johnson WBØEMU Not every output pin or input pin is equal... Some are more equal than others...
	Manual Power Control of the MaxTrac PA deck   By Robert Meister, WA1MIK When a MaxTrac (on any band) is run out of it's designed frequency range the power control routines in the firmware get confused. Unfortunately the confusion causes the radio to run the PA deck wide open, which can burn it up. This writeup gives a workaround.
	Volume Control Replacement   By Robert Meister, WA1MIK If you have a MaxTrac or GM300 series radio that runs at full volume all the time, or either turning the volume control has no effect or causes a huge jump in volume, then you have a broken volume control (a common problem). It's a simple, inexpensive fix and this writeup walks you through the repair.
	A Squelch Mod for the MaxTrac / GM300 / M120   By Barry Sloan VE6SBS       Barry's web site       Original offsite copy This simple mod minimizes the squelch tail duration - a useful feature on consistently strong signals (such as on point-to-point links). And if you want, you can add a switch to make the modification selectable at will. Just add a toggle switch in series with the lead of the capacitor.
	Converting an 800 MHz talkaround MaxTrac to a 902 MHz Repeater Receiver   By Robert Meister, WA1MIK An 800 MHz MaxTrac mobile with the talk-around option makes a good 902 MHz link, control or repeater receiver. This writeup walks you through the process.
	Converting Other 800 MHz MaxTracs to the 900 MHz Ham Band   By Robert Meister, WA1MIK A continuation of the above article based on followup information.
	Replacing the front-end filters in 800 and 900 MHz MaxTracs   By Robert Meister, WA1MIK This article describes how to cleanly remove and install new front-end filters in these radios. A companion article to the ones above and below.
	Extending the MaxTrac 900 MHz VCO Frequency Range   By Robert Meister, WA1MIK and David Malicki, N1OFJ How to move the 900 MHz MaxTrac VCO down to 902 MHz.
	Getting the MaxTrac 900 MHz radio to fully cover 902-928 MHz   By Robert Meister, WA1MIK An expansion of the articles above and below, with detailed analysis. Also shows a way of adding a manual deviation control if your radio needs it.
	Changing the MaxTrac 900 MHz VCO switch point   By Robert Meister, WA1MIK The MaxTrac 900 MHz radio's VCO has two ranges. This article explains why, and shows how to change the frequency where the range is switched. This will extend the useful operating range of the transmitter.
	MaxTrac initialization programming choices   By Robert Meister, WA1MIK A follow-up to the article below that details the once-only screen fields you must fill in when initializing a radio.
	Converting a 900 MHz MaxTrac from Trunking to Conventional operation   By Robert Meister, WA1MIK Replacing the firmware, blanking the board, and complete initialization steps.
	Converting a 900 MHz MaxTrac from Trunking to Conventional operation - An Alternate Method   By Greg Stahlman KJ6KO This article assumes that you have read the article above first.
	Hex-editing the 900 MHz MaxTrac MDF file   by Robert Meister, WA1MIK This article describes the process that you have to do so you can easily program your MaxTrac on amateur 900 MHz frequencies. You can find it in the Motorola RSS & RIB articles section of this web site.
	Transmitter Spurious Outputs when run at less than rated power   By Robert Meister, WA1MIK The myth about running radios at less than rated output power: plausible or busted? The author does some simple experiments and analysis.
	That annoying "cli-click" when the PTT button is released   By Robert Meister, WA1MIK Some radios do it, some don't. The author traced the source and shows several ways to get rid of it.
	Microphone Hang-up Mechanisms   By Robert Meister, WA1MIK A primer on hang-up buttons found on MaxTrac mikes, but the same schemes are used by a lot of other Motorola radios, and some similar schemes are even used on radios made by other manufacturers.
	Converting a 146-174 MaxTrac or Radius to 220 Mhz   By Matt Krick, K3MK This is NOT a beginners project, it requires serious surgery, access to a milling machine, and is best done to a radio that has a blown up PA deck.
	Converting a low-band MaxTrac to Six Meter Operation   By Robert Meister, WA1MIK All of the steps necessary to make a 42-50 MHz radio operate in the 46-54 MHz range. Two radios were converted; the trials and tribulations, plus the results, are summarized here.
	The Ontario Hydro Low-band MaxTrac 99-Channel Conversion   By Robert Meister, WA1MIK Documentation and procedure for converting a 42-50 MHz low-band radio.
	Overview of the DeskTrac Station   By Robert Meister, WA1MIK Model numbers, connectors, interface signals, front panel overview, photographs. A lot of the information came from the DeskTrac Service Manual.
	MaxTrac Transmit PL Mute Circuit   By Robert Meister, WA1MIK A simple circuit that immediately mutes the transmit PL tone. Especially helpful on radios that don't have a 16-pin accessory jack.
	Converting a MaxTrac 146-174 MHz radio to 136-162 MHz for APRS use   By Robert Meister, WA1MIK Some MaxTracs work on 144.39; others do not. Bob analyzed the radio's performance on both range splits and tells you what needs to be done to improve operation below 146 MHz. This was suggested by Scott KBØNLY who modified a bunch of radios in his area for APRS.
	Getting a Line Output signal from a MaxTrac radio   By Robert Meister, WA1MIK Often, MaxTracs are used to monitor police and fire calls in garages and fire departments. These are usually noisy environments and amplifiers and loudspeakers are installed to boost the signal. As always, there are multiple methods of interfacing to MaxTracs, but by far the hardest unit to use is the one with the 5-pin accessory jack. Here's a fairly painless way to get the desired signal out of such a radio. Step-by-step instructions are provided so even a technician who's unfamiliar with the radio can make it work.
	Getting Discriminator Audio from a 5-pin MaxTrac radio   by Scott Withrow, KC9LQV MaxTrac and Radius mobiles with 5-pin accessory jacks are often overlooked because they lack signals such as discriminator (flat) receiver audio. Scott duplicated the circuitry from a 16-pin radio and added it to his 5-pin radio to get flat audio out of it. This article shows what he did.
	Self-Quieting Frequencies   Compiled by Robert Meister, WA1MIK GM300, MaxTrac, Radius, and MaraTrac mobile radios all share designs and components, so they all suffer from this problem. Here's a collection of frequencies that these radios can generate internally; some of them can be annoying.
	Packet / APRS connections to the MaxTrac / Radius / GM300 series radios   Offsite link to the KPC-3 page at the web site of Earl Garber, N3EG Covers three different sets of connections: (1) to the front microphone jack, (2) in parallel with the front panel to logic board connector, and (3) the rear accessory jack. You can pick the one you want to use.
	MaxTrac Secrets   By Robert Meister, WA1MIK Communications, code plug, and other internal data secrets of the MaxTrac-series radios.
	MaxTrac Adjustments   By Robert Meister, WA1MIK More than you ever wanted to know about the various pots and coils on the RF boards of the MaxTrac-series radios, and how to adjust them. Of course Motorola doesn't want you to twiddle with these, but occasionally it's necessary.
	Making a repeater with an ID-O-Matic II and two radios   By Will Martin KA6LSD The Motorola R.I.C.K is a nice product but it has several shortcomings. The ID-O-Matic II not only gives you the necessary CW ID, but it also processes audio and has all the timers you'd need for making a repeater with a pair of MaxTrac, Radius, GM300, or CDM mobile radios. This article shows some circuit improvements and how to wire the accessory connectors. Click here to go to the ID-O-Matic II web page.

Manuals and Documentation:       If anybody wants to contribute additional part numbers (or even manual scans) we will post them.

	MaxTrac 100 and 300 User Manual   6880901Z04   389KB PDF file   Donated by A. Nony Mous
	Radius M10 User Manual   6880903Z05   1.34MB PDF file   Donated by A. Nony Mous
	User's "cheat sheet" for the Radius M10, M120 and M130   6880902Z96. Save your money, if you have an IQ higher than that of egg white, you don't need this.
	Radius M100, M208 and M216 User Manual   (early)   6880901Z47   770KB PDF file   Donated by A. Nony Mous While the title page says M100 and M200, there never was a M200 model... this book covers the M100, M208 and M216. The later book is 6880900Z45
	M120 User Manual   6880902Z97   1.33MB PDF file   Donated by A. Nony Mous
	M130 User Manual   6880903Z64   1.29MB PDF file   Donated by A. Nony Mous
	GM300 User Manual   6880902Z09   1.37MB PDF file   Donated by A. Nony Mous Early version manual, covers both 8 and 16 channel units.
	GM300 8-Channel Conventional User Manual   6880902Z26-A   56.6 KB PDF file   Donated by A. Nony Mous
	GM300 16-Channel Conventional User Manual   6880902Z41-B   58.3 KB PDF file   Donated by A. Nony Mous
	GM300 Accessories Brochure   743 KB PDF file   Donated by A. Nony Mous
	GM300 Programming Manual   6880902Z36, about $30 This is just the RSS manual; it does NOT include the RSS itself.
	M10 Service Manual   6880903Z03, about $28     This covers the XVC series of radios.
	M120 Service Manual   6880902Z98, was about $29 (but has been canceled)
	M130 Service Manual   6880903Z65, about $30
	MaxTrac Detailed Service Manual   6880102W84, was about $30 but is no longer available (NLA). This is the low band, high band, UHF, and 800 MHz MaxTrac service manual that covers the MGA, MJA, MQA, MWA and AHA models. If you ever pop a cover on any of those models then you want this book on your shelf... it's chock full of good stuff. You occasionally see these books on eBay and the other auction sites.   Until then... Part 1 Pages 001 thru 058   4.3 MB PDF Part one has the manual index, model charts, assembly breakdown tables, performance spec tables, options, general information, block diagrams and the front panels Part 2 Pages 059 thru 081   15.4 MB PDF Part 2 has all of the Logic boards including the HLN5172, HLN5173, HLN9123 and HLN9313. Part 3 Pages 082 thru 125   41.4 MB PDF Part 3 has all of the RF boards including the HLB4099 (29.7-36), HLB4100 (36-42), HLB,4101 (42-50), HLD4321 (136-162), HLD4322B (146-174), HLD4322C (144-174), HLE9310 (449-470), HLE4424 (?), HLE4425 (403-430), HLF4095B (800 non-talkaround, single VCO), HLF9122A (talkaround, dual VCO). Part 4 Pages 126 thru 163   17.1 MB PDF Part 4 has the PA deck info, radio disassembly / assembly procedures and the exploded parts lists Total download of the MaxTrac service manual is 75.3 MB. Originally this book arrived as a shrink-wrapped pile of 3-hole punched pages - you had to provide your own thick 3-ring binder. The shrink-wrapped stack was slightly over 2 inches tall.   Personally, I used a 3.5" (ring diameter) binder to hold this W84 manual, a 900 MHz Trunked manual (complete with the 30 watt Power Amplifier Supplement), a DeskTrac manual, an RSS manual, some web page printouts, and a dozen sheets of 3-hole punched paper with some modification and programming notes.
	MaxTrac 900 MHz Service Manual   6802980G40   was about $12 but is No Longer Available (NLA). This is the 900 MHz MaxTrac Conventional service manual (the 900 MHz MaxTrac trunked radio service manual is part number 6802977G10). This manual deals with the 12w radios. It also has the info on the HMN1038A desk microphone and the HLN5309A "Desk Tray" - the plastic base station stand that holds the radio in a comfortable position for use. If you have the 30 watt radio you need the supplement below. Other than the test modes, this manual covers the trunking models as well. You occasionally see these manuals on eBay and other auction sites. By popular demand, this manual was donated by Bob WA1MIK and scanned by Eric WB6FLY. 25MB PDF file.
	MaxTrac 900 MHz 30 watt Power Amplifier Supplement   IMR200   probably not available separately. This is the 30 watt Power Amplifier Instruction Manual Revision (supplement) that came with a 6802977G10 Trunking Service Manual. It applies to conventional radios as well; the only difference is the firmware and front panel escutcheon. Note that the 30w model is rated for 30w on 896-902 MHz (i.e. the repeater input range) but only 20w on the talk-around / simplex 935-941 MHz range. This manual was donated by Bob WA1MIK and scanned by Eric WB6FLY. 580 kB PDF file.
	Radius M100, M206, M208, M214 and M216 VHF / UHF / 800 Service Manual   6880101W58-A   7.55 MB PDF This manual was about $45 when it was available and is the manual that covers all of the Radius LRA series except for the low band and 403-430 MHz radios.   Low band and low range UHF were added in the revisions.   I've never seen a 900 Mhz LRA Radius. A large number of the board diagrams and service section of this manual are the same as the MaxTrac Detailed Service Manual. You need to include all of the Instruction Manual Revisions below into the manual. All of them include revised model tables. MMR005   3.9 MB PDF   Among other things this revision describes the HLN9123A Logic board, HLN5173B Logic Board, the HLF9122A RF board, the HLD4321B, HLD4322B and HLE4425B RF boards, the HLD4326A, HLE4431A and HLE4432A PA boards. MMR009   2.7 MB PDF This revision adds the 403-430 MHz RF boards (HLE4424A, HLE4430A, HLN9153A). MMR012   2.61 MB PDF This revision adds the HLN9313A Logic board and lists the chassis kits that are affected. MMR013   2.63 MB PDF This revision corrects parts list errors in MMR012 and contains service information on the low-band 42-50MHz HLB4101A RF board, the and HLB4107A PA board, the hardware kit, and other parts. MMR016   2.65 MB PDF This revision (1) notes that the new HLE9310A RF board replaces the HLE4425A and HLE4425B 449-470MHz RF boards, and (2) introduces the HLF3030A RF power amplifier (which consists of the HLF4098A PA board and HLN9305A PA Hardware kit). MMR023   2.95 MB PDF This revision contains service information on the low band 29.7-36 MHz HLB4099A RF board, the HLB4105A PA board, the hardware kit, and other parts. The PA board, hardware kit and other parts make up the HLB3048A RF PA Kit. MMR028   788 KB PDF This revision contains service information on the UHF band 449-470 MHz HLE9502A two watt PA board, the HLN9501A hardware kit, and other parts. MMR030   2.88 MB PDF This revision contains service information on the low band 36-42 MHz HLB4100A RF board, the HLB4106A PA board, the hardware kit, and other parts. The PA board, hardware kit and other parts make up the HLB3049A RF PA Kit. MMR048   41 KB PDF Comments on the M206, M208, M214 and M216 radios. Click here to download a 28.7 MB zip file containing the 6880101W58-A manual and all the revisions.
	GM300 Service Manual   6880902Z32, was about $13 (No Longer Available as of June 2007) This service manual covers the GMC and GMR models of the GM300 radio. This is another one you want on your shelf... You occasionally see these on eBay and the other auction sites.   Until then... Part 1 Pages 001 thru 030   14.4 MB PDF Part 1: the cover page and the manual revisions (including the HLN8070D and HLN8074E Logic boards, the HLD8265A and 8266A RF boards and the first part of the HLD8293A PA Deck). Part 2 Pages 031 thru 072   14.5 MB PDF Part 2: Pages 1-6 of this file has the rest of the revisions including part 2 of the HLD8293A PA Deck and the accessory connector instructions. Page 7 of this part is the first page of the basic manual. The rest of part 2 is the table of contents, the model charts, accessory lists, performance specifications, disassembly and re-assembly instructions, alignment instructions, theory of operation, a list of jumper-selectable options, the HLD8029A, HLD8031A, and part of the HLE8229A and HLE8230A RF boards. Part 3 Pages 073 thru 077   9.9 MB PDF Part 3: the rest of the HLE8229A and HLE8230A RF boards, plus the HLE8300A, HLE8301A, HLE8263A and HLE8264A RF boards. Part 4 Pages 078 thru 085   8.4 MB PDF Part 4: the HLE8227A and HLE8228A RF boards, and the HLN8074A and HLN8070A logic boards. Part 5 Pages 086 thru 144   15.1 MB PDF Part 5: the HLD8299A, HLD8033A, HLD8287A, HLE8275A, HLE8267A, HLE8034A, HLE8271A, HLE8284A, HLE8269A PA Decks, 01-80704Y83 filter board, HLN8075A Display board, HLN8071 Volume/mic jack board, HMN3596A/HMN3413A/01-80704Y98 microphone, radio exploded view, and all parts lists. Total download of the GM300 service manual is 62mb.
	GR300 and GR500 Service Manual   6880903Z42-A   9.31 MB PDF This manual covers: a) the GR300 and GR500 housings, b) the fan assemblies, c) the power supplies (GR300=HPN8393, built by Astron and GR500=HPN9005, built by StarWerks), d) the HLN3948 Basic Controller, the HLN8389 Zetron ZR320 ("Selective Calling Repeater Controller"), the HLN8390 Zetron ZR330 ("Remote Telephone Interface"), the HLN9119 Zetron ZR340 ("Tone Remote Adapter Repeater Controller"), the HLN9004 Instrument Associates i50R ("Basic Interconnect Repeater Controller") and HLN9121 TRA100R ("Advanced Interconnect Repeater Controller"). This manual does not cover the HLN9447 Instrument Associates i20R, the HLN9120 i750R or the HLN8388 Zetron ZR310 (community repeater controller), however the ZR310 service manual is avaialble for download from the Zetron page at this web site.
	GR300 and GR500 Controller Programming Manual   6880903Z43-A   5.51 MB PDF This manual covers the programming of the HLN3948 Basic Controller, the HLN8389 Zetron ZR320 ("Selective Calling Repeater Controller"), the HLN8390 Zetron ZR330 ("Remote Telephone Interface"), the HLN9119 Zetron ZR340 ("Tone Remote Adapter Repeater Controller"), the HLN9004 Instrument Associates i50R ("Basic Interconnect Repeater Controller") and HLN9121 TRA100R ("Advanced Interconnect Repeater Controller").
	Instrument Associates was bought out by GAI-Tronics Corp. Reading, PA. They are at 800-492-1212.

Some additional GM300 information is available from Colin Lowe G1IVG at http://www.g1ivg.com/motgm300.htm (offsite link).