Electronics and Technical resources from vu3dxr
Microphone Audio Compressor in SSB Radio Single-sideband (SSB) radio, a dominant mode in amateur (ham) radio and other communication applications, transmits voice signals with improved spectral efficiency compared to older AM (amplitude modulation) methods. However, SSB has limitations in terms of audio quality and intelligibility, particularly in challenging propagation conditions. This is where …
Series Modulated AM Transmitter A series modulated AM Transmitter is a type of radio transmitter that uses amplitude modulation (AM) to transmit audio signals over a carrier wave. It’s known for being low-power and simple to construct, making it a good option for beginners or those interested in QRP (low-power) applications. In a series-modulated AM …
Class E – AM Transmitter A Class C AM transmitter is a type of high-efficiency, solid-state transmitter that is popular among amateur radio enthusiasts. It is known for its simplicity, affordability, and efficiency compared to other types of transmitters. Unlike Class E’s switching operation, Class C amplifiers operate in a more “on or off” manner. …
Dynamic speech compressor or simply audio compression is an audio signal processing operation that reduces the volume of loud sounds or amplifies quiet sounds, therefore reducing or compressing an audio signal’s dynamic range. Compression is commonly used in sound recording and reproduction, broadcasting, hearing aid, live sound reinforcement, and in some instrument amplifiers. There are …
A simple series modulated AM QRP HF transmitter is a type of radio transmitter that uses amplitude modulation (AM) to transmit audio signals over a high frequency (HF) radio band. It is designed to be low-power and simple to construct, making it a good choice for beginners or those who want to build a QRP …
The OXO QRP HF transmitter is a simple, low-power CW (continuous wave) transmitter designed by George Burt, GM3OXX. It is a single-band transmitter that can be built to operate on any of the amateur radio bands from 160 to 20 meters. The transmitter is built around a few standard transistors and a crystal oscillator. It …
Simple audio compressor for SSB HF Radio rigs An audio/speech compressor is a device that reduces the dynamic range of the audio signal. This means that it makes the loud parts of the signal quieter and the quiet parts of the signal louder. This can be useful for SSB HF radio rigs because it can …
The circuit shown is a microphone speech compressor built around operational amplifier LM324. This amplifier circuit exhibits gain and also continually adjusts that gain to maintain a constant amplitude output signal, regardless of the amount of signal coming from the microphone. The microphone is coupled to the LM324 Operational Amplifier IC which has 4 separate …
Amateur Radio – End fed Halfwave antenna – Web resources and links An end-fed half-wave (EFHW) antenna is a type of radio antenna that is a half-wavelength long and has its feed point at one end. This makes it a very simple and compact antenna, and it is often used for portable or temporary applications. …
The Really cheap audio compressor circuit diagram from www.freestompboxes.org is a simple, yet effective compressor circuit that can be built with a handful of cheap components. The circuit consists of two op-amps, two LEDs, a LDR, a few resistors, and a capacitor. The first op-amp (U1) is configured as a unity gain amplifier. The input …