Morse Code Transmitter II
We're going to make a Morse code transmitter that can send out Morse code signals by radio. Your friends can hear an AM radio at some distance away from you.
In this project, we send out a radio wave at a frequency around 800 -1770 kHz, so we need to find such a spot where there are no stations in this range.
Take a look at the schematic. You see that U1 work as an oscillator generating Morse code signals when S1 is pressed.
Transistor Q1 is used as a modulator, and you can adjust the degree of modulation with the control volume.
U2 is used as an AM radio frequency oscillator. The frequency is set by C2 to be around 530 to 800 kHz. You can adjust the frequency by using different values for C2. If you find the frequency you choose for your transmitter is used by some station, you can select another frequency by changing C2. Use lower value capacitor to shift the frequency higher.
When you finish wiring up the circuit, erect an antenna with a length of about 1 m, set the control volume in the 12 o'clock position, and turn power ON.
Tell your friends to turn the dial of the AM radio while you are turning S1 ON and OFF. If they receive your Morse code signals, adjust the signal sound by turning the control volume. Now, you can send your message to your friends by Morse code!