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Tr circuit – Circuit Schematic
Tr circuit
R1 and R2 are Va or Vi W carbon composition resistors. K1 is a 12 V DPDT DIP relay. Illustration A shows how to connect the relay contacts for use with a separa...
Pll receiver – Circuit Schematic
Pll receiver
This simple AM circuit uses a 561B. There's no inductance/capacitance tuning circuit. The 365 pF capacitor connected between pins 2 and 3 does all the tuning. T...
Radar signal detector – Circuit Schematic
Radar signal detector
The circuit can be tuned to respond to signals between 50 MHz and 500 GHz. The economy model is shown in Fig. 1, and the deluxe model is shown in Fig. 2.The fir...
One-chip radar detection circuit – Circuit Schematic
One-chip radar detection circuit
A simple X-band radar detector is capable of indicating changes in rf radiation strength at levels down to 2 mW/cm2. Radiation falling on the detector diode, pr...
650Mhz amplifying prescaler probe – Circuit Schematic
650Mhz amplifying prescaler probe
The 650 MHz Prescaler Probe's input is terminated by resistor Rl and is fed through Cl to the diode limiter composed ofD1 through D4. Those diodes are forward-b...
General purpose rf detector – Circuit Schematic
General purpose rf detector
This circuit provides a dc output to a meter and an audio output (if necessary) for checking transmitters or modulated signals....
Single injector-tracer – Circuit Schematic
Single injector-tracer
In the "Trace" mode the non-linear operation of the amplifier will detect modulated rf signals which will be filtered by the .001 µ¥ capacitor and heard ...
Rf-genie – Circuit Schematic
Rf-genie
A variable oscillator covers 3.2 to 22 MHz in two bands—providing coverage of 80 through 15 meters plus most crystal-filter frequencies. Optional 455 kHz...
Receiver for 50 khz optical transmitter – Circuit Schematic
Receiver for 50 khz optical transmitter
For maximum range, the receiver must be designed in the same manner as a radio receiver front end, since the received signals will be similar in both frequency ...
Video modulator circuit – Circuit Schematic
Video modulator circuit
These are modulator circuits for modulation of video signals on a VHF/UHF carrier. The circuits require a 5 V power supply and few external components for the n...
amplitude modulator – Circuit Schematic
amplitude modulator
This simple diode modulator delivers excellent results when used for high percentage modulation at low signal levels. Constants are shown for a carrier frequenc...
RF modulator – Circuit Schematic
RF modulator
An RF input is applied to the primary of Tl, which applies equal amplitude, opposite phase RF drive for output FETs Ql and Q2. With no AF modulation at points A...
Transmission indicator – Circuit Schematic
Transmission indicator
Everytime the push-to-talk button is closed the light will go on. The antenna samples the output RF from the transmitter. That signal is then rectified (detecte...
High-sensitivity field strength meter – Circuit Schematic
High-sensitivity field strength meter
A TL081 (IC1 op amp is used to increase sensitivity. RF signal is detected by CR1 and is then amplified by IC1....
Rf sniffer – Circuit Schematic
Rf sniffer
This circuit responds to RF signals from below the standard broadcast band to well over 500 MHz, and provides a visual and audible indication when a signal is r...
Field-strength meter II – Circuit Schematic
Field-strength meter II
"Minimum-parts" field-strength meter is shown here. For more distant testing, add the dc amplifier. ...
Field-strength meter – Circuit Schematic
Field-strength meter
The antenna consists of about 20 cm of insulated stranded wire glued or taped around the inside of a small plastic box. ...
High frequency peak detector – Circuit Schematic
High frequency peak detector
National Semiconductor's DP8464B is primarily intended for use in disk systems as a pulse detector. However it can be easily used as a general purpose peak dete...
SCA decoder – Circuit Schematic
SCA decoder
The circuit uses a Signetics NE565 PLL (Phase-Locked Loop) as a detector to recover the SCA signal. The input to the SCA decoder circuit is connected to an FM r...
Sine wave descrambler – Circuit Schematic
Sine wave descrambler
This decoder features a sine wave recovery channel and uses a PIN diode attenuator driven by the sine wave recovery system to cancel out the sine wave sync supp...