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Simple FM transmitter – Circuit Schematic
Simple FM transmitter
This transmitter can be tuned to the FM broadcast band, 2 meters,-or other VHF bands by changing C5 and Ll. The values given for C5 and Ll will place the freque...
1-2Mhz broadcast transmitter – Circuit Schematic
1-2Mhz broadcast transmitter
T1 is a low impedance output transformer...
27Mhz and 49Mhz rf oscillator-transmitter – Circuit Schematic
27Mhz and 49Mhz rf oscillator-transmitter
The modulator and oscillator consist of two NPN transistors. The base of the modulator transistor is driven by a bidirectional current source with the voltage r...
Wireless am microphone – Circuit Schematic
Wireless am microphone
Transistor Ql and its associated components comprise a tuneable rf oscillator. The rf signal is fed to transistor Q2, the modulator. Operational amplifier ICl i...
Rf oscillator – Circuit Schematic
Rf oscillator
This rf oscillator is useful up to 30 MHz...
Shortwave fet booster – Circuit Schematic
Shortwave fet booster
This two transistor preselector provides up to 40 dB gain from 3 to 30 MHz...
Vhf preamplifier – Circuit Schematic
Vhf preamplifier
This simple circuit gives 15 dB gain and can be mounted on 1 in 2PCB. Coil data is given for 85 to 95 MHz...
Wideband uhf amplifier with high-performance fets – Circuit Schematic
Wideband uhf amplifier with high-performance fets
The amplifier circuit is designed for 225 MHz center frequency, 1 dB bandwidth of 50 MHz, low input VSWR in a 75-ohm system, and 24 dB gain...
600W rf power amplifier – Circuit Schematic
600W rf power amplifier
A unique push-pull parallel circuit. It uses four MRF150 RF power FETs paralleled at relatively high power levels. Supply voltages of 40 to 50 Vdc can be used, ...
Audio-rf signal tracer probe – Circuit Schematic
Audio-rf signal tracer probe
This economical signal tracer is useful for servicing and alignment work in receivers and low power transmitters. When switched to RF, the modulation on any sig...
Rf probe for vom – Circuit Schematic
Rf probe for vom
This probe makes possible relative measurements of rf voltages to 200 MHz on a 20,000 ohms-per-volt multimeter...
Rf probe for vtvm – Circuit Schematic
Rf probe for vtvm
This circuit combines a 555 timer with a 2N2222 transistor and an external potentiometer. The pot adjusts the output voltage to the desired value. To regulate t...
Transmitter-oscilloscope coupler for CB signals – Circuit Schematic
Transmitter-oscilloscope coupler for CB signals
To display an rf signal, connect LI to the transmitter and points A and B to the vertical plates of the oscilloscope. Adjust LI for minimum SWR and C3 for the d...
Wideband noise generator – Circuit Schematic
Wideband noise generator
This circuit will produce wideband rf noise. It uses a reverse-biased diode and has a low-impedance output...
Rf modulator – Circuit Schematic
Rf modulator
Capacitors Cl, C3, C5, and C6 should be dipped mica. C4 and C7 are compression or piston trimmer types. R6 is PC-board mount trimpot...
Tv modulator – Circuit Schematic
Tv modulator
The VHF frequency is generated by a tuned Hartley oscillator circuit. Resistors R2, R3, and R4 bias the transistor, with tapped inductor LI and trimmer capacito...
Tv modulator – Circuit Schematic
Tv modulator
The FM oscillator/modulator is a voltage-control led oscillator, which exhibits a nearly linear output frequency versus input voltage characteristic for a wide ...
Cb modulation monitor – Circuit Schematic
Cb modulation monitor
Connect this circuit to a transceiver with a coaxial T connector in the transmission line. Key the transmitter (unmodulated), set 31 to CAL, and adjust R2 for a...
Visual modulation indicator – Circuit Schematic
Visual modulation indicator
Indicator lamp brightness varies in step with modulated RF signal. Adjust R2 with transmitter on (modulated) until the lamp flashes in step with modulation...
Modulation monitor – Circuit Schematic
Modulation monitor
Broad-tuned receiver demodulates the RF signal picked up by a ioosely coupled wire...