AT90S2323 Microcontroller 418MHz RF Transmitter 2 Channel
The transmitter is constituted by AT90S2323 microcontroller and TLP434 RF transmitter module at 418MHz. I have designe the transmitter for more battery economy and safe transmition of the data.
* The battery economy is made it by the use of powerdown mode of AVR. In this case the AVR goes [...]

The original CK217 was an improvement on the CK200 FM Transmitter. This new FM Transmitter can transmit over 900 feet in the open depending on aerial used. The tank oscillator coil is built into the circuit board, and has been tinkered with to give the best distance and stability for it’s size. The battery supply [...]

500 KHz to 1600 KHz AM Transmitter Circuit
The circuit is in two half, an audio amplifier and an RF oscillator. The oscillator is built around Q1 and associated components. The tank circuit L1 and VC1 is tunable from about 500 KHz to 1600 KHz. These components can be used from an old MW radio, if [...]