Simplex repeater operation

Simplex repeater for PMR446 and CB-phones

Operation:

Firmware: repeater07.hex
When switching power on to the repeater, ISD-chip goes to standby mode.
In this mode, ISD-chip current consumption is minimum.
At the same time, green RX-led blinks two times. User can now see that repeater is ready for operation.
Just a time after that, red TX-led goes on and repeater sends beacon sound to the phone.
Repeater VOX-circuit is activated when squelch is open and audio signal is enough strong.
VOX-circuit sends pulsing +5V audio to the PIC:s RB0 pin.
ISD-chip is enabled and recording starts. At the same time green LED goes on.
When VOX-signal is off about 1,5 seconds, recording stops and green LED goes off.
Recording and playback are limited to the 75 seconds. This have been done with software and hardware
with ISD-chips EOM (End-Of-Message) and OVF (Overflow) pins.
So result is receive and transmit watchdogs. Repeater transmits only when channel is free of traffic.
At the waiting time, green LED blinks with 0,5 second cycles.
When channel is free of traffic, transmitting begins.
When message is repeated, short beep-voice is played back.
If there was traffic in the channel, different end of message beep-voice is played back.
Then transmit is ended and red LED is turned off.
Next ISD-chip is turned off.
Repeater sends beacon voice every five minute.
Beacon, end of message, and waiting channel sounds are different.

Firmware: repeater076.hex
Just like repeater07.hex, but without beacon sound.
Power consumption is very low, because PIC-chip is also turned off.

Firmware: repeater08.hex
Just like repeater07.hex, but beacon sound is replaced with 10 minute morse beacon.
Modify your own morse message to the .ASM and convert it to the .HEX file with Microchip MPLAB IDE.
There is already pre-programmed morsecode CQ RPT in the firmware.