Thia unit is a slide-out drawer from a PURC5000 paging transmitter. It was used as a 72MHz link receiver to receive analog modem tones from a paging control point. The audio then fed the controller in the PURC5000 to digitally moduate the transmitter with Pocsag or other data.
These drawer units make great stand alone repeater receivers or link receivers. I've used a few as link receivers wired to ports on a multi-port repeater controller, The 10-pin connector on the rear provides audio, cos, pl detect, and feeds the unit its +12v and ground connections. It is the same type of connector used to connect a COM port DB9/25 jack to a motherboard inside a pc. The unit houses a Micor RF/IF board and a slightly modified Micor base station version audio/squelch board. The difference is that that resistor/capacitor network on the preamp stage is tailored for flat audio (to accomodate the paging modem tones). You can simply compare this stage to a Micor base/repeater to make it the same. I usually remove the 0.0056 cap and install a 12k resistor on a repeater board - this gives a nice response to match the Micor exciters. I think this version board has a 15k resistor and no cap, so the the low end response is down a few db. You can experiment to tailor the stage to your preference. One other thing - since this was a 72MHz version, most likely there is a cap or two (or three) in the squelch circuit that has been optimized for a 72MHz receiver - once again simply compare the board to the VHF/UHF station manual, and you can easily convert it to a VHF/UHF version. If you neglect to change the two or three caps involved, the worst case is that the squelch control may need to be higher than normal for closure. At least that has been my experience when using an unmodified board from a mid-band station in a VHF or UHF Micor station. Rather than messing with that connector, which by the way was fed with nothing more than a ribbon cable, and could cause potential duplex issues, simply take an 8-conductor 22ga shielded cable and hard-wire it into the unit's main interconnect board. Then take the other end and install whatever connector you need for your controller. And use a piece of dc power zip cord for the dc connections. BTW, there is a separate manual for this receiver. It came as an addition to the PURC5000 Paging Station manual. It covers the main chassis interconnect board, the various version audio/squelch boards, and almost every Micor RF/IF board from 30MHz thru 900MHz. I think I have a spare copy in my office somewhere. Anyone care to scan it for the RB site? If so they can have it. Eric KE2D --- In [email protected], "Bob M." <[EMAIL PROTECTED]> wrote: > > One of my 900 MHz PURC5000 manuals has several Micor receivers in it, including 72 MHz. There's also a section that seems to cover the chassis, although I don't know if it's the same one you have. It might be. One board has a squelch pot and an RJ45 jack on it. If that's mounted directly behind the front panel, then it just could be the same board. There's also room inside the chassis for a DPL decoder board and a flat audio board. I suspect these same modules would fit into a SpectraTAC chassis but I haven't checked the pinouts. > > There's a ribbon cable from the main interface board to the rear panel. The schematic shows the pinout of that connector. Nothing magic but the flat cable does make a mess of the various signals. > > I would expect you could put ANY wide-band Micor receiver into the unit and it would work just fine. I don't know how the unit interfaces with the parent station, but obviously it can be done. > > I thought I had a full manual for that exact chassis. I still might; just haven't come across it yet. > > Bob M. > ====== > --- On Sun, 9/21/08, [EMAIL PROTECTED] <[EMAIL PROTECTED]> wrote: > > > From: [EMAIL PROTECTED] <[EMAIL PROTECTED]> > > Subject: [Repeater-Builder] Motorola MICOR Receiver enclosure questions > > To: [email protected] > > Date: Sunday, September 21, 2008, 1:35 PM > > I recently picked up a 72-MHz MICOR receiver off of the big > > auction site (won't mention the name lest someone get > > all [EMAIL PROTECTED]&!).. This MICOR receiver appears to be in a > > 3-1/2" high MSF-5000 series box, with the spring-loaded > > releases on the black front panel. It has a squelch control > > and an RJ-series jack on the front panel, and the rear panel > > has a BNC antenna jack, along with a 10-pin male plug. The > > Motorola P/N stamped on the rear is TRC1072AB, which might > > be just something like the rear panel number and not the > > complete assembly number. > > > > Does anyone know what series station this receiver was used > > in? I'd like to find the hookup info for it, and find a > > part number the 10-pin matching connector. I have plenty of > > actual MICOR receiver info, for receivers of all bands, and > > would like to use this as a UHF control receiver for a > > 2-Meter repeater. Repeated request for info emails to the > > original seller have not been responded to, so I"m > > trying here. One person in our shop felt it might be part of > > an MSF-5000 sereis paging station, with this 72-MHZ receiver > > used for control (maybe similar to a 330W MICOR PURC station > > on 42 MHz with its 72-MHz receiver, which I have sitting in > > my garage.) > > Larry >
