A Note about different MICOR Station Models - There are several basic versions of the MICOR, and they are significantly different in regards to the backplane. These versions include basic RT or RA (repeater or base), CR (Community Repeater), Securenet (DVP and DES), PURC (Paging Universal Remote Control - Paging Station), and Trunking repeater. There are also a gazillion SP versions which are not standard production models. The SP's almost always have plating cuts and re-routes on the backplane. You can always transplant a RT/RA backplane (TLN5644A) into any other unified chassis......highly recommended if you have an SP Station. You can salvage one, or I have had good luck with getting some of them (PURCs for example) new from Motorola Parts.

In spite of what a Motorola shop might tell you, there are still a significant number of MICOR modules available from Motorola parts. If you have the bucks, get a new squelch gate module....the latest version (TRN6689B) is real nice, has DIP switch jumper selection, and selectable In-Cabinet-Repeat (ICR) (see below). The squelch gate module from a trunking station is unique and has missing parts. it won't work without restoration.

The Securenet and PURC models have a special exciter which accomodates digital modulation. They work just fine. The primary difference is in the IDC hybrid and won't affect speech. PURC's can make fine dedicated transmitters, even if they are not configured with internal receivers. They are intended to pass normal audio for 2-tone paging formats. But, get the manual.

To keep your life simple, stick with an RT or RA station, and try to get one that was a repeater configuration from the factory....it has additional receiver filtering. Avoid DVP stations (we'll take it!), Community Repeaters (we don't want 'em), PURCs (we'll take 'em), and trunking stations. RA's (base station configuration) are just fine...you'll just want to make sure you have all the shields in place and rejumper them for RT operation. The difference is the "full filtering option" which is additional chokes and caps for better RF filtering in duplex (repeater) operation. The unified chassis models which have full filtering are TCN1190A and TCN1225A.

So, Whatcha got there?

As a first inspection of a station you might be considering, check the module complement:

• If it has multiple PL or DPL cards and a Master decoder, you have a community repeater chassis.

• If it has only F1/PL, Guard Tone, Station Control, and Line Driver, you have a factory wireline tone control base station. You may also encounter a base station or repeater station which has a DC transfer module instead of F1/PL and Guard Tone, which is a DC control station. That's fine. They can be converted to tone control very easily, and are interchangeable with a couple of jumper changes. If you are never going to use tone remote control, you can keep the DC transfer module.
  
  You will have to have either a F1/PL-Guard Tone pair OR a DC transfer module for the station to key up and pass transmit audio in stock configuration, along with a station control module.
  
• If it ALSO has a squelch gate, you have a factory repeater. You will need a squelch gate to use it in stock configuration.
  
• If you have Simulcast, Digital Modulator, Alarm Logic, VAR, and a line driver with a bunch of jacks on the front of it, you have a PURC ( Paging Universal Remote Control ) station. It may or may not have a receiver in it, and the receiver may or may not be the same band as the transmitter. (It might have been a UHF transmitter with a 900MHz link receiver for example. It is a repeater of sorts). If it is a PURC and it has no digital modulator module or card guides for it, the station was set up for a separate paging synthesizer and Hi-stability oscillator. Another hint for this is an exciter channel element compartment lid with a BNC connector on it. Also, look for a T/R relay....if it has one, then it was not a link, it used a receiver to inhibit transmission if the channel was busy.
  

While you are inventorying the modules, look to see if there are card guides installed that do not have modules in them. This is a clue as to how the station is configured (jumpered).....i.e., a squelch gate or an encoder may have been robbed from the station. The module positions are labled on the chassis. If you have card guides in the next-to-the-left-most slot with no module, you likely have a station which was voted, especially if it has a Spectra TAC Line Driver.

Last, look at the backplane. A stock RA/RT backplane (TLN5644A) has no extra wires running around between the modules. Watch out for backplanes with wiring that clearly was not done by the factory. Who knows what you might have. Carefully inspect the entire backplane for cut traces.

Did you get burned and wind up with an 800MHz chassis? All is not lost. An 800MHz station exciter is the same thing as a low-split VHF exciter (!) with a different model number. Stash it for building a 2-meter rock-controlled station. It is a conventional repeater chassis and backplane, you can change out the power amp, do this mod, and have a VHF or UHF station with some jumper changes and the right modules.

Some example chassis and backplane numbers:

Transparent UHF DVP Repeater Station: QRN4039A backplane, TCN1273A Chassis

UHF PURC Station: TRN4860APR backplane