allan crites <[EMAIL PROTECTED]> wrote: Date: Wed, 23 May 2007 16:51:22 -0700 (PDT) From: allan crites <[EMAIL PROTECTED]> Subject: Motrac Rcvrs & PL encoder / decoders To: [email protected]
Kris and John, There were no Motorola Motrac base stations built. Only beige colored " upright" ( as they were referred to at Motorola) transistorized models which were developed after the Motrac mobile development (which stations had two tubes in the xctr and one or two tubes in the PA depending on the output power and power supply) which was called instant death at Mot. because of no switching relay heard when the PA B+ was switched on. Many confuse the " upright" base station with the Motrac mobile because of the casting used in the mobile was the same as one used in the base rcvr. If one follows the history of the transistorized rcvr used in the mobile, one will find it was adapted for use in the base sta.rcvr with a variety of audio pcb's depending on the application and which were not interchangeable with mobile models. The original Motrac rcvrs, low band, high band, and 450 models, had heated xtals, ( 25-45 MHz for LB, 28-32 MHz for HB, and 48-49 MHz for the 450's) had the designation "H" in the model number and the 1st mixer was a diode. A later "H" HB version had heated 36-39 MHz xtals. The HB "L" rcvr came next with a preselector casting and with a bipolar transistor mixer, and the heated xtals were replaced with the channel element. The HB and 450 "M" versions were designed as having an FET in the 1st mixer along with a xtal filter in the 8 MHz IF HB and a 11.7 MHz xtal filter in the 450 version. There was also a Motorola rptr station designed with a 450MHz "M" rcvr replacing the "B" tube type rcvr in the L44BBB-3100A station. Along the same time frame was a Compa Station designed using the Motrac mobile xmtr and rcvr in a short cabinet and a side mounted PS followed by a Consolette station also using a mobile xmtr and rcvr with a horizontal AC PS, in all LB, HB, and 450 models. All this time the rcvr audio pcb underwent many revisions. Kris- If the rcvr in your station is a TLN 6962A it is obviously a CS model and the audio pcb is not convertible to use the original copper PL reeds. If you have the TLN 6966A then the rcvr should have a reed socket mounted on the front of the rcvr casting. You need to have an in depth look at what you have. I suggest an external PL encoder/ decoder as it would be more versatile for your applications. WA9ZZU
