I saw one several years ago - the guy started with a MSR base station that had been toasted after the antenna was struck by lightning (i.e. toasted the PA deck and the receiver front end transistor).
He converted the receiver and exciter to 220, and I don't have the conversion information (if I did there would be a 220 Mitrek / 220 MSR conversion article). The technique is the same as a Mitrek mobile since the MSR receiver and exciter are essentially each a half of a Mitrek main board. The MSR PA deck heat sink was stripped and three 220MHz power bricks bolted to it. The first one took the exciter output and amplified it enough to drive a Wilkinson power divider, which drove two bricks. He used teflon circuit board and etched the divider tuned lines onto it. The two bricks drove a Wilkinson divider in reverse (i.e. a combiner) which drove the RF output jack. There was a shared receive antenna (three separate 220 systems used it) at 100 feet and a dedicated transmit antenna at about 40 feet. There was a single 220 MHz cavity between the exciter and the PA deck, and I don't know if it was to clean up the exciter or for some other reason (perhaps notching out a bit of grunge on the receiver input?). The modified unit was re-labeled as a C73 1/2 GRB - that was an inside joke as Motos model number definition system used a 3 for high band and a 4 for UHF, so a 3 1/2 had to be 220 Mhz. The converted base station played on 220 for years and ran totally solid. It was connected to one port of an RC850 with a 2m and 440 remote base on another port. I lost track of the unit when the owner passed away and a couple of months later it evaporated from the building. So somewhere "out there" is a 220mhz MSR2000. Mike WA6ILQ At 08:43 PM 04/05/10, you wrote: >If it can be done with a VHF MSR I would like to know, since I have >two of them sitting around doing nothing. ;) > >--- In [email protected], "WA2RJP" <jlang...@...> wrote: > > > > Has anyone attempted or succeeded in converting a VHF MSR2000 to > 220? I'd rather not reinvent the wheel if someone already has done or tried. > > > > tnx, > > > > Jim
