MAY5

Simplex Repeater for two-way radios

For longer range of two-way radios using an external antenna is in most cases just enough. In cases where it is not possible or simply not enough (or not allowed) a repeater is used. Repeater is nothing new to amateur radio (HAM) operators and they all know that it uses different transmitting and receiving frequencies. Setting up the radio to repeater-mode is no big deal but with FRS radios repeater-mode is not implemented at all.

Because of this, using FRS radios on classic repeaters is not possible (or very hard). Solution is to use a Simplex Repeater. Simplex Repeater is, again, not a big deal with amateur operators but for FRS users it might be. This repeater receives your signal on one channel, records it internally and re-emits it on the same channel once you stopped transmitting. These are also called "Parrot Repeaters".

Here is a complete Simplex Repeater project that consists of PIC microcontroller and ISD (information storage device) IC-circuit which in combination with an additional FRS two-way radio make a perfect Simplex Repeater.

simplex2