Sub Audible Tone Encoder
The Communications Specialists continuous tone encoder is a wee one, about VA" long, 7/8" wide and high. It uses the resonant reed made by Motorola or Bramco to determine the exact frequency. The oscillator will operate over the range from 67 to 3000 Hz.
The unit pictured has a Motorola 4A reed plugged in, resulting in a continuous 14L3 Hz tone being generated. There are a few repeaters that are turned on by this type of tone instead of the more ordinary carrier operated system. These are listed in the Atlas with a "PL" or 'TL4A " If you run up against a PL type of repeater without knowing it, frustration can set in rapidly. You can hear fellows talking with each other over the repeater even though you cannot break through. These are in use by some repeaters who wish to be more exclusive than others such as WA2UZE on Long Island and WA2UWR in New Jersey. PL stands for Private Line, a Motorola patent and trade marked term.
The above encoder costs $14.95 wired and tested from Communications Specialists, Box J53t Brea CA 9262J. The reed is an extra $17.50. The connections are simple - 12 volts and one audio wire. The unit is small enough to fit inside of just about any FM transceiver made.
Continue reading here: Simpson Model B
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