A note from Mike WA6ILQ:
Prices quoted below are early 2008 prices, and Eric's employer has a NSO account (National Service Organization, available to Motorola service shops and large end-users). Prices availalable to any individual reader of this page will most likely be higher. On top of that, Moto adjusts their prices quarterly, so a few months from now the prices listed will probably be different.

73, Eric Lemmon WB6FLY

To: Repeater-Builder From: Eric Lemmon WB6FLY Now that I have some hands-on experience with MTR2000 repeaters, I can pass along some suggestions. 1. The MTR2000 Depot Service Manual 68-81096E35 ($184.45) contains the admonition that any signal to the auxiliary audio input (pin A17) MUST be AC-coupled through a 100 uF electrolytic capacitor. Failure to have this capacitor in line will upset the bias on opamp U4509, which is DC-coupled to the backplane connector. Some controllers have DC-coupled or transformer outputs, and may not work well sans this capacitor. 2. Rather than mess with mismatched connectors from Digi-Key or Mouser, simply buy the "System Connector Kit" from Motorola, P/N 30-83908X02, for $55.46. This kit includes the proper connector body, along with 30 wires already terminated with male pins. 3. The current RSS for the MTR2000 is RVN4148P, version R03.03.02, at $278.00, and is not backward-compatible. 4. The essential accessories needed to program and test the MTR2000 station are: a. Programming cable 30-82056X02, $50 (DE-9F on one end, 8-wire modular on the other end) b. Amplified speaker HSN1000, $97.75 c. Speaker cable 01-85180U01, $15.51 d. Microphone GMN6147B, $59.93 This is a three-button microphone that uses the additional buttons to adjust the volume and select the mode (channel). Yes, the MTR is a multi-channel base station or repeater. Routine testing cannot be performed without the microphone plugged in. Here is the info needed to use this microphone, scanned from the MTR2000 Service Manual. 5. When installed in a rack, the MTR2000 should be mounted on standoff brackets to keep the units center of gravity centered. Motorola offers some nifty brackets designed just for the job: part number 07-84384T03 at $66.73 for the pair. 6. This Is Important! Note that the high-power (100 watt) VHF station comes in two splits: 132-154 MHz and 150-174 MHz, and the higher split can NOT be made to operate in the 2m band. This restriction only applies to the 100 watt power amplifier, all other components of the station, along with the 30 watt and 40 watt power amplifier cover 132-174 MHz. I have read a number of "horror stories" about clueless hams who bought used commercial MTR2000 repeaters with 100 watt PAs, and then discovered that they can't program them below 150 MHz. Caveat Emptor! How do you tell if the repeater has the 100 watt PA? It's easy: only the 100 watt PA has a fan on each side, one for the PA and one for the high-capacity power supply. By the way, the MTR does not use the traditional Motorola numbering scheme (like C73RCB3106BT) to indicate the band and power level. You have to decode a bunch of cryptic Field Replaceable Unit ("FRU") numbers in order to identify exactly what you really have, and these labels are not always visible! A list of the FRUs is here. 7. Buyers of a new MTR2000 can save several hundred dollars by deleting the wireline (tone control) interface card and the AC power supply. However, be aware that the 100 watt PA operates on 28 VDC, while all other PAs run on 14 VDC. 8. All MTR2000 stations have only one two-circuit PowerPole connector for the backup battery. That's true whether the station has an AC power supply or a DC power supply. The only difference is that the high-power stations expect 28 VDC to be applied to that connector, while low-power stations expect 14 VDC. The high-power stations, both AC and DC powered, use 28 VDC for the PA and have an internal 14 VDC regulator for running everything else.

A note from Mike WA6ILQ:
Several of the larger Motorola base stations, including the MTR, use Anderson Power Pole connectors (or the AMP Corp. clone) for the DC backup battery connection. Rather than purchase them at a premium price from Moto you can get them from Digi-Key (1-800-344-4539) for less:

• 53880-4-ND Connecting terminal 6-10 AWG Crimp power lock (two needed, assuming that you don't ruin one as you learn...)
• 53884-1-ND Blue connector housing
• 53884-3-ND Black connector housing
• 53884-4-ND Red connector housing

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