This circuit is a powerful three stage, 9V FM transmitter (Tx) with a range of up to 1 kilometer in the open. It uses an RF transistor in its output stage and two BC547’s for the first two stages. Distance of trans-mission is critically dependent on the operating Conditions (in a building or out on the open), type of aerial used (single wire or dipole), operating voltage (12V is better than 6V) and if the circuit is peaked for maximum performance.
Components List:
| Resistors, 5%, 1/4W: 100R 1 470R 1 4K7 1 22K 1 39K 1 47K 2 1M 1 | Capacitors: Trim cap 5-20pF, red – 1 5.6 pF ceramic – 1 10p ceramic – 2 47pF ceramic – 3 1nF ceramic – 1 20nF or 22nF ceramic – 2 100nF monoblock – 2 | RF transistor ZTX320 – 1 Small signal transistor BC547 – 2 6 turn tinned copper coil – 1 6 turn enamelled coil – 1 8 turn enamelled coil – 1 9V battery snap – 1 Electret microphone – 1 PCB-mounted SPDT switch – 1 Antenna wire 1.6m |
If you’re interested in RF circuit, then you should khow about this basic RF oscillator.
This basic RF oscillator circuit is easy to build and the components are not critical. Most of them can be found in your junk parts box.
The L1 antenna col can be made by close winding 8 to 10 turns of 22 gauge insulted hookup wire around 1/4 inch form such as a pencil.
This is a simple audio Pre-Amplifier with single transistor 2N3904.
This easy circuit provides good gain to weak audio signals such as electret microphone. Use it in front of an RF oscillator to make an RF transmitter that’s very sensitive to sound.
This information is provided by circuitdiagram.net, the collection of electronic circuit diagram.
