What you can hear*** is a CW-ID produced by a little circuit using a PIC 16F627 (or 16F628) microprocessor. The CW-ID is repeated every 3 minutes. The time between the transmissions may be selected during programming of the PIC and can also be set higher. Before the CW-ID starts the transmitter is keyed through a transistor which is switched by one of the port bits of the PIC.
The CW-ID keyer needs a DC power supply between 7 and 16 V. It draws only a few mA of current. The audio output is connected to the microphone or data input of the transceiver and the keying output is connected to the PTT. The keying voltage of the transmitter is assumed to be positive.
The PIC may also be programmed with a longer message ( ~150 characters with the 16F627 and even more with the 16F628) and the circuit can be used as a beacon.
I am using my CW-ID keyer on our local 2 m simplex channel if there is no one on to indicate that I am qrv. The transmission of the keyer starts as soon as the voltage is applied to the circuit and is repeated every 3 minutes.
Figure 1 shows the schematic of the keyer and Figure 2 is a picture of the printed circuit board I build for HB9DHK.
Because the schematic is simple you can build the circuit also on a breadboard. The code for the keyer is available for download here.
*** If you hear nothing you may download the small audio file here : ID-Keyer sample