Two in one Radio with Transceiver
Here is a circuit to build a transceiver with a radio set by using only two external components, viz, a 3-pole, 2-way bandswitch and a loudspeaker as microphone.
The gadget works in two modes:
In mode you can listen to programs as on an ordinary radio set. IN mode 2 the gadget works as a transmitter. A conventional npn radio circuit has been shown so that it would be easier to connect the band switch and the microphone. The circuit is already present in your radio set. Just connect the bandswitch and microphone as shown. The speech is amplified and modulated with the radio amplifier section built in the radio. The audio frequency is fed to the converter stage. There it is oscillated and converted into radio frequency.
The RF is transmitted with the help of antenna. Tune to a band where no radio program is heard. Use that point for both transmission and reception.
When one person keeps the radio in mode 2 and transmits the signal, the other person should keep his radio in mode 1 for receiving the signal. For better reception and transmission use external antenna and adjust the volume control. The given component values are for commonly used 6-V NPN type radio set. Values of resistance and condenser may vary slightly from set to set.