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Need help identifying this Motorola repeater

Posted: Tue Apr 13, 2010 7:39 am
by njh621
These two figures came straight from the USAF Titan II ICBM field maintenance tech order for the Radio-Type Maintenance Network, which comprised of all Motorola equipment. To me this looks like either a Micor (because of the test set), or some kind of specialized MTR-300. Any idea?


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Re: Need help identifying this Motorola repeater

Posted: Tue Apr 13, 2010 11:43 am
by Will
Micor station/repeater. Probably a mid power VHF or UHF. Still a preferred station for repeater or base station use. Still lots of them in HAM use.

There are numbers like TLB, TLD, TLE that cah give us a idea of the frequency range.

There is some information at www.repeater-builder.com in the Motorola section.

Re: Need help identifying this Motorola repeater

Posted: Wed Apr 14, 2010 9:36 am
by RADIOMAN2002
Based on the picture of the RX section, either low band or more likely VHF.

Re: Need help identifying this Motorola repeater

Posted: Wed Apr 14, 2010 11:41 am
by njh621
I know for a fact it's a VHF system, because that's what the portables (SP MX340s) are.

A couple lingering questions that hopefully someone can answer:
1) The base station was connected to two consoles in the control center, so that the crew can transmit using this repeater by pressing a button at either console. They use the standard telephone handset at the console as a mic. Any idea how they would interface the station with a system like that? Maybe it's just as simple as a connector going from the base station which has wires for PTT/Mic/Speaker etc, and then Martin (now Lockheed Martin) tied it into the communication systems panel from there.

2) Another function that can be triggered (via push button-indicator) from the console is called 'RADIO NET OVERRIDE'. When activated, only the crew in the control center can transmit from the consoles (using the repeater), and regular portable-to-portable communication is cut off. Any idea how this is possible?

Re: Need help identifying this Motorola repeater

Posted: Wed Apr 14, 2010 1:49 pm
by Hartley
That station has a Squelch gate card, a station control and a line driver, so it should have full audio and control available on screw terminals on the back of it. 2 or 4-wire audio, receive and transmit signaling.

It would be easy to configure the station to inhibit repeat and repeated audio if a lead was exerted.

Re: Need help identifying this Motorola repeater

Posted: Wed Apr 14, 2010 7:15 pm
by Will
Hartley wrote:"That station has a Squelch gate card, a station control and a line driver, "
And a single tone decoder like the State of California repeaters and base stations.

'RADIO NET OVERRIDE' Disables the repeat function of the station.

Re: Need help identifying this Motorola repeater

Posted: Thu Apr 15, 2010 10:45 pm
by PETNRDX
Looks like a pretty standard Micor VHF, 100 watt intermittent duty, DC remote control station with 4 wire audio and repeat.
The telephone remotes are actually DC remotes.
The single tone decode module can be wired up to do many different things.
The radio net over-ride sounds like "supervisory control" for example dispatchers can disable the repeater so that it functions only as a "remote base".
Probably that is what the single tone decoder module does also.
Micors have literally hundreds of possible configurations (maybe thousands).

Re: Need help identifying this Motorola repeater

Posted: Sat Apr 17, 2010 1:09 pm
by njh621
Thanks for all of the information. The purpose for the RADIO NET OVERRIDE was for emergencies/propellant transfer operations. The idea was the crew commander or deputy commander could override portable traffic to provide evacuation instructions/etc. Looking at TO 21M-LGM25C-1 (the "owners manual" for Titan II) RAD-1 (the rack the repeater was housed in) also had its own battery backup system that was supposed to last for 8 hours in the event of an AC power failure. Interesting...

So, if I were to purchase this exact same hardware today, would do you think I could get it for? I'm hoping I might find some of this stuff at Dayton.This is another personal project I'm working on for the missile museum in Tucson. Before the higher ups officially approved saving the site for a museum, it was still being deactivated along with the other 17 sites in Tucson. The missile crews managed to slow ball item removal from the museum site and returned most of what was removed, but unfortunately the RTMN cabinet was one of the victims of deactivation, and the equipment was never returned. I suppose that's where I come in.

Re: Need help identifying this Motorola repeater

Posted: Sat Apr 17, 2010 3:32 pm
by PETNRDX
My guess is you could get one or make one for around a hundred bucks.
If you wanted it fully functional on the correct frequency ( a bad idea probably ) and with duplexer, then quite a bit more.
Since the Micor is not narrowband, they should be pretty inexpensive.
You might even find someone that would make a "mock up" non-working one pretty cheap.
Especially at Dayton.

Re: Need help identifying this Motorola repeater

Posted: Sat Apr 17, 2010 8:14 pm
by njh621
Non-functional would be fine, as the museum has a modern Motorola repeater installed that is UHF (whereas the original USAF system was VHF), and they are using the original antenna system (RADIAX coax). The museum-installed repeater works pretty well!