Advertisement
Noise Blanker – Circuit Schematic
Noise Blanker
This noise blanker takes a sample of IF input voltage, amplifies it, and drives a switch. The switch (when activated by a noi...
Mixer Diplexer – Circuit Schematic
Mixer Diplexer
By inserting a high-pass filter section in the IF lead, this mixer is terminated at all frequencies, besides the IF, for oth...
Programmable Identifier – Circuit Schematic
Programmable Identifier
Used on an amateur or experimental radio beacon, the above ID circuit will generate any callsign or message program...
Gasfet Frequency Doubler – Circuit Schematic
Gasfet Frequency Doubler
This circuit will produce over +10 dBm in the 1800-3 000-MHz range. Drive power is 7 dBm in the 900-to-l 500-MHz r...
Ssb Generators – Circuit Schematic
Ssb Generators
These two circuits are SSB generators. One uses a crystal filter by KVG Electronics at 9 MHz, the other uses a 455-kHz mecha...
Rf Attenuator – Circuit Schematic
Rf Attenuator
A balanced mixer is used as a control element in this circuit. An Analog Devices AD7524 D/A converter drives a voltage-contro...
Tuned Rf Wavemeter – Circuit Schematic
Tuned Rf Wavemeter
Ll and L2 form a tuned transformer. About a 1:3 turns ratio is optimum. L2 and CI tune to the desired frequency. The fre...
Rf Output Indicator – Circuit Schematic
Rf Output Indicator
A simple RF detector circuit using a visual indicator can be useful for an RF output indicator, etc. This circuit was u...
Bandswitched Grid Dip Meter – Circuit Schematic
Bandswitched Grid Dip Meter
For checking resonances, tuned circuits, antennas, etc., this circuit covers the 2-to 20-MHz range. Ql serves a...
Frequency Shift Keyer – Circuit Schematic
Frequency Shift Keyer
Apply a signal to each differential amplifier input pair. When the gate voltage is changed from one extreme to the ot...
Transmitter Negative Key Line Keyer – Circuit Schematic
Transmitter Negative Key Line Keyer
Using an NTE288 (or ECG288, GE223, or SK3434), this circuit can key a negative line up to - 300 V maxim...
Visual Cw Offset Indicator – Circuit Schematic
Visual Cw Offset Indicator
An NE567 tone decoder, tuned to the transceiver"s CW offset frequency, ensures that the transceiver will be tran...
Tunable Bandpass Filter – Circuit Schematic
Tunable Bandpass Filter
One of the difficulties in the design of higher-order tunable bandpass filters is achieving correct tracking of the...
Signal-Strength Meter – Circuit Schematic
Signal-Strength Meter
This field-strength meter is useful for antenna testing. It covers 6 to 60 MHz and uses a rugged 0-to-l mA meter. A 9...
Radio Direction Finder – Circuit Schematic
Radio Direction Finder
This RDF circuit consists of a square-wave oscillator (IC1), which switches two antennas alternately at an audio rat...
Ic Product Detectors – Circuit Schematic
Ic Product Detectors
These product detectors use IC devices. SSB and CW signals can be detected with them. The circuits should be useful up...
Am Envelope Detector – Circuit Schematic
Am Envelope Detector
This general-purpose detector for AM envelope detection can be used in many receiver applications. T1 matches the IF a...
Noaa Weather Alert Decoder – Circuit Schematic
Noaa Weather Alert Decoder
This circuit detects the 1050-Hz tone sent by the NOAA (National Oceanic and Atmospheric Administration) Weather...
Rf-Field Detector – Circuit Schematic
Rf-Field Detector
This detector is a half-wave rectifier for RF, which then feeds an op amp. U1A acts as an amplifier, driving meter Ml. Th...
Ssb/Cw Product Detectors – Circuit Schematic
Ssb/Cw Product Detectors
These circuits are used for product detection of single-sidebound (SSB) and CW signals. BFO injection is typically...