Variometer Crystal Radio
#crystal radio
#variometer
#RF
#tuning
#receiver
#AM radio
#coil
#antenna
#detector
#passive components
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Active Antenna
Antennas that are much shorter than 1/4 wavelength present a very small and highly relative impedance that is dependent on the received frequency. It is difficult to match impedances over a decade of frequency coverage. Instead, input stage Q1 is...
Two Homing type Direction-Finding
The antenna consists of two vertical dipoles. Diodes in each dipole allow the circuit to select which antenna is active at any given time. When a positive voltage is sent up the coax feedline, diode D1 conducts and D2 blocks,...
Nostalgic Crystal Radios
Aside from the diode, which requires a PbS (Lead Sulfide) galena crystal for replacement, all components visible in the circuit for the non-powered version can be constructed using enamel wire, aluminum cooking foil, cardboard wax, and similar materials. The challenging...
Parts and schematic for an AM radio transmitter
User Agreement & Disclaimer Disclaimer All files are found using legitimate search engine techniques. This site does not and will not condone hacking into sites to create the links it lists. It is assumed that all links found on the...
Sensitive RF Voltmeter Probe
Sensitive RF Voltmeter Probe Circuit. This circuit measures RF voltages beyond 200 MHz and up to about 5 V. PARTS LIST: R1 - 4.7 MΩ, R2 - 1 MΩ, R3 - 1 MΩ, R4 - 100 kΩ, R5 - 330...
Bandswitched Grid Dip Meter
This circuit is designed for checking resonances in tuned circuits, antennas, and similar applications, covering a frequency range of 2 to 20 MHz. Q1 acts as an oscillator that can be tuned across this range using capacitor C1 and band-switched...
80M
This 80M receiver design incorporates the necessary switching mechanisms to enable the SSB filter and first intermediate frequency (I.F.) amplifier to function for transmission purposes. The receiver stages, from the radio frequency (R.F.) input to the speaker output, will be...
mk484 am radio circuit design project
The MK484 AM radio circuit offers a comprehensive solution featuring an RF amplifier, detection, and an automatic gain control (AGC) circuit. It requires only a few external components to achieve high-quality AM tuning. The circuit has an input impedance of...
wave antenna circuit
The circuit illustrated here demonstrates that, despite advancements in components and technology, it remains possible to design effective and intriguing circuits. This design utilizes two well-known transistors, the BF256C and the BF494. Along with the necessary resistors and capacitors, these...