Voltase hobby

Youll find that this is a very easy project to build. It will transmit good quality sound in the FM band ( 88 - 108 mhz ). One inportant item is that the IC chip operates on 3 volts DC. The chip will get destroyed if it is operated on any voltage higher than 3.5 volts. The antenna can be a standard telescopic antenna or a 2 foot length of wire. The input is in the millivolt range and you may need to add additional pots for the inputs. I was able to use this schema for a walkman and a portable CD player in my car. I used the headphone jack on both and varied the signal with the volume control.

Circuit Diagram

To adjust the schema tune your FM radio to a quite spot then adjust the trimmer capacitor C8 until you hear the signal that you are transmiting. When you have a strong signal adjust the resistor R4 until the stereo signal indicator lights. If the input is to high of a signal you may over drive the IC chip. Use two 15 turn pots on the input signals to bring the level down. You can balance the signal by using headphones. The inductor L1 is 3 turns of .5 mm wire on a 5 mm ferrite core.

Sourced: Circuitsstream

This schema is a video transmitter that has many uses, such as video cameras, security cameras, satellite receivers, DVD, Video Games, etc. .. The schema transmits 470-580MHz and can be tuned in the UHF channels 21-34. The video transmitter can reach up to 300 meters in open field using a wire antenna of 10-20 cm.

TV Video Transmitter Circuit Diagram



Video Transmitter

Transmitter can work with a voltage from 9 to 15 volts. However, you can also use a 9v battery. Oscillator is based around BF199 and BFR90 is the RF transistors. If necessary, the transmission power can be increased by replacing with BFR90 transistor 2N3886.