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Motorola® MTR2000 Base Station and Repeater Information and Modifications

If you are looking for information on the MTR300 Fire Tower repeater please go to the MX handheld page (since it was built by repackaging a pair of MX handhelds into the sheet metal frame originally designed for a Micor auxiliary receiver or a Spectra-Tac voting receiver).

The main manual for the MTR2000 is the Installation and Operation Manual 6881096E20, priced in the $20 range.

The original MTR2000 VHF and UHF catalog sheet   This is a PDF of the original glossy catalog sheet.   73kb PDF The original MTR2000 800 and 900 catalog sheet   This is a PDF of the original glossy catalog sheet.   148kb PDF Interfacing the MTR-2000 to an external controller   by the Reno Ham Radio Club W7RHC Some notes on the MTR2000   by Eric Lemmon WB6FLY Read this article before buying either a new or a second-hand MTR2000. It contains some excellent information including an important caution to anyone contemplating buying an MTR. A List of Module Numbers in the MTR2000   by Eric Lemmon WB6FLY In some cases the only way to determine what you have is to inventory the Field Replaceable Units (FRUs). Here is a list from the MTR manual. Factory duplexer option   986 KB PDF (11 pages) of 68P81086E71 One of the options from Motorola for the VHF MTR2000 is an in-cabinet duplexer. See the table below for the option number to order when ordering a duplexer with a Quantar or MTR2000 station. The unit that Motorola supplies is a relabeled Celwave model PD5042-1. The performance of this six-cavity pass-notch duplexer can be better than 100 dB isolation between transmitter and receiver. Range (MHz) Part Number Option Number 132-146 0185417U01 X182AA 144-160 0185417U02 X182AB 158-174 0185417U03 X182AJ More details on this duplexer can be found here and here. Programming the transmitter idle frequency on the MTR   by Eric Lemmon WB6FLY What to do when exciter/transmitter local oscillator leakage is a problem (this is mandatory if you are running an MTR on a simplex channel, and nice when on a repeat channel and you are local to the site). Motorola Field Service Bulletin FSB10174   donated by by Eric Lemmon WB6FLY Issue 1: MTR2000 station locks up in transmit with no PL. Issue 2: MTR2000 station does not transmit an analog audio on wireline line 2. Motorola has identified a firmware issue in all versions prior to and including version R003.04.002 and has a warranty fix. The PDF file linked above includes a software order form. Setting up the MTR2000 for Battery Backup   by Eric Lemmon WB6FLY Especially when you are on a budget... The DC power cable that comes with a DC-only MTR2000 station is Motorola part number 3082009X02, which comes with the station or can be purchased as a service part for about $40. It is 10 feet long, with #8 AWG stranded wires, one black and one red. The same cable fits the backup DC connector on the back of an AC-powered MTR2000, but the receptacle is normally covered with a piece of sheet metal. The 75A PowerPole connectors are red and black, stacked vertically, with black on top and the other wire ends are stripped. There is a 30 ampere cartridge fuse in the red wire, one foot from the stripped end. If you want battery backup on your MTR2000 that has the built-in AC supply you can clone or buy the 3082009X02 cable and use the above circuit developed by Eric Lemmon. The above photo shows how you need to configure the 75 amp PowerPole connectors on the #8 DC cable so it will mate with the MTR2000 or the Quantar system DC connector. Motorola wants you to use this: The Argus Switched Mode Charger   1.43mb PDF donated by Eric Lemmon WB6FLY This is the Model L1883 Battery Reverting Charger, model "010-519-20" or "010-523-20", made by Argus Technologies in Britsh Columbia, Canada for the MTR2000 station. It is a much more complicated device than its catalog description implies, perhaps justifying its significant cost ($1451 new, dealer cost is $1222 in 2004). As noted in the manual, it must be used with an MTR2000 that includes a power supply, since its purpose is to provide only a charging and equalizing function for the backup batteries, along with various alarm and monitoring capabilities. The L1883 model is intended for the 30 and 40 watt MTR2000 stations that operate on 14 volts; the 75 and 100 watt stations must use the L1884 28 volt version. Note that to use the Argus with the MTR2000 it must be connected with the following items: 1) CDN6226A Charger Load Cable. This is intended to connect the output terminals of an Argus Battery Backup/Charger Unit to the MTR2000. This is about 10 feet of #8 red and black stranded wires and is not fused. It has the 75 ampere PowerPole connectors on one end (the DC power connector for the MTR2000 is arranged one over the other, with black on top) and the other end has ring lug terminals for the 1/4" studs on the back of the Argus. The price was $40 to $45 in 2005. 2) CDN6227 Charger Battery Cable. Goes from the Argus to the local battery. 3) TDN9879 Temperature Sensor

From an email to repeater-builder:

The MTR is a very nice unit, and the internal controller will do 80%-90% of what most any amateur system needs to do... the unit has a connector on the back that is designed for Motorola's Mobile Radio Telephone Interconnect (MRTI) unit and all the interfacing can be done through that.
One quirk : the microprocessor that controls the repeater internals will not pass its own power-on-self-test with the transmitter PL encoder inhibit line (pin 24 of the the 25 pin MRTI connector) grounded (i.e. active). So if your needs include switching the internal PL encoder on and off (it's a handy thing to have thru a controller output to use for level setting) make sure that as you program up your repeater controller you set up a timer to make sure that this line is not asserted until after the self-test is finished. The simplest way is to use a timer in the start-up macro to inhibit all repeater operation for the number of seconds that the self test takes, plus a one or two extra.

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