Foxhunt transmitter
This 2 meter 144 MHz transmitter is used in amateur competitions where a hidden transmitter is to be “hunted” using mostly homebrewed receivers and antennas. The featured electronic circuit is the transmitter. It radiates a high quality signal without unwanted harmonics. Transistor T1 and the crystal togheter make the oscillator that generates a 36MHz signal.
The unwanted 12MHz basic frequency of the oscillator is supperssed by the filter circuit made of L1, C3, C2. The L2/C4 circuit is set to the fourth harmonic or 144 MHz. The signal goes to the dual-gate-FET driver stage before finally radiating through the transmitting antenna. The output power is from 10…40mW.
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Fm transmitter
This transmitter circuit is designed to be used for aligning FM radio receivers. It has a microphone amplifier with automatic gain control. The FM modulation is a voltage oscillator and the final stage is built with MOSFETs. A lowpass filter at the output assures the transmission of a clean 10 … 50 mW FM signal. IC1 works as an amplifier supplying a negative control voltage to FET T1. The amplitude of the amplified audio signal can be adjusted through P1. The carrier frequency is generated by the oscillator T2.
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Thomson 32LB220B4/U Chassis IFC228-LCD
Here you can download the service guide manual which contains the components list, schematics, layouts and troubleshooting of the LCD TV Thomson 32LB220B4/U on Chassis IFC228-LCD.
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