The unit is a 100 watt UHF transceiver. They can be moved to the 440-450 band if you are willing to do a lot of work and have the proper test equipment (or access to same).
Going from memory... The Micor UHF mobiles used a single channel element for frequency determination. The channel element sets the RX frequency injection 21.4 MHz below the operating frequency. The same signal is sent to the transmitter board where it is mixed with another signal from the offset oscillator. If the offset oscillator is 21.4 MHz the radio will then transmit on the same frequency it receives on, ie simplex. If the offset oscillator is 26.4 MHz the transmitter will generate a signal 5 MHz above the receive frequency for use on a repeater. Obviously any drift in the receive element will be reflected in thye transmit signal. The output of the transmit mixer went through a narrow filter that tuned to the transmit frequency range. The filter output fed a low level amplifier, which then fed the PA. This radio can function nicely as a mobile or base station within a limited range of frequencies. As I recall, the receiver was narrow, maybe 1-2 MHz and the transmitter was 500 KHz. Some radios had two offset oscillators and two filters for repeater and simplex operation. Remember that this is 30 year old technology. I'd make sure that the radio works where it is currently built before trying to do any changes in frequency. Changing frequency requires recrystalling the channel element. This is best done by a crystal house such as Bomar or ICM, by sending the element in and requesting that it be recrystalled and temperature compensated. Milt N3LTQ ----- Original Message ----- From: "pooterwizz" <[EMAIL PROTECTED]> To: <Repeater-Builder@yahoogroups.com> Sent: Friday, April 04, 2008 7:13 AM Subject: [Repeater-Builder] Mot Micor T74RT3000AA > Hello fine RF People, > > I already know this is UHF mobile unit. I have the connector and cable > (s). What I need to know since I am new to all this RF stuff and think > this would make a good project is, is this all here? > > Unit was found in an old shed. Lots of corrosion in the PA section. > connectors undone and bottom cover plate missing. Not a problem. I > want to use this in the 440-450 Mhz HAM band. The only element in it (I > understand there should only be one) is for R-451.875MC/1.8340.625KC > Mot P/N KXN1024A. > > Questions, is all of this critter here? > > Can I add more elements (channels)? > > Do all these use the same key? (On the Handle) Maybe I can find the key > in this estste mess. (I have already found the (Handles) for several > pieces of test equipment, etc. There are several keyrings, maybe > something will fit this critter! > > Last, outside of getting the schematics and service manuals which I > have not fuly checked for yet but will before I begin messing with this > critter, what is needed to make this work in the 440-450 HAM band > preferably 5Mhz split for repeater access/use. > > Thanks in advance, > > Bruce (PooterWizz) Bagwell > KE5TPN > (Please note the new Call Sign since my last post!!!! > > If you can hit IRLP node #4640 call me. (Hey, being new, it sure is > nice to hear my call sign FIRST! I usually have a scanner going by the > PM. Call a few times to let me maybe get my radio up please. Maybe you > could email me to set up a contact time at bbagwell AT swbell DOT net. > > Thanks again! > > > > ------------------------------------ > > > > Yahoo! Groups Links > > >
