Hello John and others too ... JOHN MACKEY wrote: > > Neil McKie <[EMAIL PROTECTED]> wrote: > > I still have one here - is a T1411A Mark XII which is a 12 Freq > > carrier squelch, duplex radio. > SNIP > > Expected receiver sensitivity is 0.7 uv > SNIP
That's what the manual says ... ;) > I sold my last Mark XII/T44MSN/T1411/etc at the Rickreal ham swap > meet several years ago. I had a lot of trouble getting the receivers > to meet spec, & usually had to settle for about 1.0 uV. That was > typical of receivers in mobile telephone service, which usually were > listening to very strong (possibly simulcast) transmitters. In > typical land mobile, such receiver sensitivity was usually > unacceptable in a quality system. True ... > I think, in that era of equipment, a person who wanted to be duplex > would have been FAR better off to use a Motrac or Mastr Pro & modify > it for full duplex operation with seperate antennas. (Which is what > you did, Neil - I saw both your radios!) Although those radios are now out of service, I still have them. One is a GE Mastr Pro with four freq and duplexed ... the other is a UHF Motrac U64MHT - also four freq and duplexed. > The other problem with those radios, was the transmit PA. It was a > MSN 45 watt 150 MHz transmitter Actually a 30 watt tranmsmitter - I used to service them ... > with a varacter tripler on the final output. Yup. Sometimes a real squirrel to tune ... but that was part of the fun. > Not very efficient & slightly tricky to tune!! Also, the tuning of > the varactor was (of course) a capacitor & a metalic tuning tool > was basically needed for the necessary strength required to turn > that capacitor. If you happen to accidentially short across the > capacitor plates with your tuning tool, you would blow the varactor > diode. Sounds like you had the wrong Motorola tuning tool ... :( > Last time I checked probably 10 years ago, the cost of that diode was > about $145 dollars using my discounted pricing at Motorola!!!! > > Rather than buy a new diode, I waited until the next Dayton Hamvention > where I bought a whole identical radio for about $10 or $20. That > night K7LJ & I pulled out the varactor stage & trashed the rest of the > radio. Trashed the rest of the radio - that's too bad ... > The only other thing good in those readios was that they had a tunable > harmonic filter which worked well for using as a front end filter on > frequency agile radios. Example: a 440 MHz remote base to cover a 10 > MHz operating range but filter out signals on other bands or more than > 20 Mhz away. Yup ... Neil - WA6KLA > > > > Yahoo! Groups Links > > To visit your group on the web, go to: > http://groups.yahoo.com/group/Repeater-Builder/ > > To unsubscribe from this group, send an email to: > [EMAIL PROTECTED] > > Your use of Yahoo! Groups is subject to: > http://docs.yahoo.com/info/terms/ Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
