MSF5000 Repeater Interfacing Details Now Posted

[kcbooboo]

Thanks to the operators of the BatLabs system, there's a new article at the end of the MSF5000-specific page of the web site. This is the result of my effort to connect a CAT-200 repeater controller to my MSF5000, the same one I've been asking questions about here on the BBS. It's long, detailed, and might duplicate some of the efforts posted by others, but I felt the analysis was worth the time I spent doing it.

I will reply to any public or private mail sent via this BBS.

Thanks to all !

Bob M.

[Big Towers]

Bob and all, I have several UHF Analog MSFs and have just started dealing with adding a single frequency remote base to them. I am really surprised, with the amount of MSFs hitting the Ham markets, that someone hasn't come up with a simple controller or interface board for these. I have used the "Motorola Method" of Wildcards and such to get audios and PTTs in and out, but I hate to have to screw around with an accesory shelf and find wildcards to do it, and when your all done there is no Audio Level adjustments between the radios.

Is there such a thing as a simple interface with audio adjustment out there? I know that some people have hooked controllers up by connecting the wires right to the MSF's controller board. I don't need goofy voices, temperature monitors and all the other high priced stuff that comes in most ham controllers, just PTT out, Adjustable Audio Out, and the same going in, 4 or 5 wires! I have hooked up Maxtracs as remote base/link radios, but only the long/hard way with wild cards and audio pots!

Anything better out there?

[Pj]

Are you using the decommissioned AT&T MSF's?

[kcbooboo]

I had a few options:
1. configure the MSF5000 as its own stand-alone repeater, letting it handle audio and CW ID. This actually works very well, but that's ALL it does. No way to control it over the air (a wire line control was not available to me at my repeater site) and control is an FCC requirement.
2. buy a touch-tone decoder and find a way to interface it to the MSF5000 for control purposes. There was one unit for about $90 that probably would have done the job. Audio and CW ID would have been done by the MSF5000.
3. Go with a more substantial controller such as the CAT-200 or NHRC-2. As my current repeater uses a CAT-200, I went that way. This also gave me an audio delay feature. I don't use the weather or voice stuff either but it's available should I decide it's necessary. This costs around $300.

I did not look into what would have been necessary for an external touch-tone decoder to control the MSF5000. I'm sure that some form of transmit or receive disable signal is floating around somewhere in the control unit. And with the RSS you could probably program the auxiliary control input on the option connector to do what you need. But if you're going that far, might as well build a more complete controller and use the MRTI connector. The audio in and out signals are there, PTT input is there. The only signal you have to dig for, and at least it's on an available pin, is the receiver active or COR signal. The real Motorola MRTI interface even does its own squelch processing, although the MSF5000 does a nice job itself.

The interface I came up with is just a cable and connectors. There were no additional parts required between the CAT-200 and the MSF5000 controller. I only had an 8-conductor piece of cable, so I made everything work with that. If I had to make something commercial, I'd want to find a better way to interface to the Options connector on the TTRC board, and I don't know what I'd have done if I didn't have a TTRC board. I also have control of the MONITOR function to disable the PL decoder when/if I want to. I think there's still one spare wire in the cable that I could use to disable the transmit PL some day. Making that work the way I want will require a couple of discrete components, however.

"Keep those cards and letters coming, folks!"

Bob M.

[xmo]

"...I have used the "Motorola Method" of Wildcards and such to get audios and PTTs in and out, but I hate to have to screw around with an accesory shelf and find wildcards to do it, and when your all done there is no Audio Level adjustments between the radios.

Is there such a thing as a simple interface with audio adjustment out there?..."
-------------------------------------------------------------------------------------

In the commercial world of Motorola systems, it is often necessary to interface two stations to each other. Motorola calls this an 'RA' interface situation.

It is a misconception that the use of a wildcard in an analog MSF5000 is the "Motorola Method" of RA interfacing.

There is an actual RA interface kit which consists of a circuit board with transformers for interfacing an additional pair of 600 ohm transmit and receive audio lines. The board also contains audio circuitry with transmit and receive level controls. Further, it contains mux-bus circuitry to provide COR and accept PTT. This board is the proper way to interface an analog MSF5000 to just about anything.

The board is called a 'Site Interface Module'. It can be installed in the main control tray in place of the DC or tone remote board or it can be installed in an expansion tray so that the station can have both types of control simultaneously.

The part number of this board is TRN9249A. It has been a while since I checked, but it may still be available from Motorola parts. It used to cost about $300. That might seem high for ham applications - just keep in mind you are dealing with a radio that cost as much as a new car.

BTW - RA capability is built into the CXB digital capable & MSF Limited stations with four wirelines as well as PTT input and a spare output on the J2 'System Connector'

[Big Towers]

I am using a couple of MSFs that are just like the AT&T in that they came with the orderwire system and DTMF decoder for shutting off the repeater or keying it continually.

Bob, I think your system is a Digital MSF and I am not sure the analog even has a MRTI connector, haven't looked. The Wildcard method described on the Batlabs site does basically work for getting audio in and out, but as I said, a lot of stuff for not much. Basically just need an audio processing interface, the PTT stuff is pretty simple as well. Just thought somebody out there may have seen the possibilities and started making either full blown controllers or simple basic interfaces.

I don't want to interupt the repeat audio path in the radio nor lose the CWID, just want audio out to feed a maxtrac and audio in to put some back from the maxtrac receiver (or other radio).

Just saw the other post. In my current price guide, no such part number. Will call and ask tomorrow, but unlikely. I knew Motorola had to have something out there as this isn't a new idea like Nextels Push to Talk ( ), but they ain't a Micor when it comes to ease of getting ins and outs. ANYBODY have a manual with schematic and parts list for this interface?

[xmo]

I checked for the RA board with Motorola Online & came up dry, however, they do still list the manual: 6881115E11 @ $12.46 DNUP

[Radio_Cowboy]

Are you using the decommissioned AT&T MSF's?

We are getting a ham group together at work, and we were just given 2 of these old AT&T MSF's. Is there anything special about them?




-RC-