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Category «radio»

Dynamic speech compressor with audio preamplifier

Dynamic-compressor-with-audio-preamplifier

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 …

Simple series modulated AM QRP HF Transmitter

Simple series modulated AM QRP HF Transmitter

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 …

OXO QRP HF Transmitter

OXO-QRP-HF-Transmitter

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

Simple audio compressor for SSB HF rigs - PCB Layout

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 …

LM324 microphone speech compressor

LM324 Microphone speech compressor-PCB layout

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 …

Really Cheap audio compressor

Really-cheap-compressor-circuit

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 …

DIY 80M Trapped dipole antenna

80M-Trap-dipole-antenna

This 80M Trapped dipole antenna is the work of Nadisha 4S7NR, modified by YC0HLE which results are matched at a frequency of 3,845 MHz. This design will be resonant at a frequency of around 3,250MHz to 3,850MHz. Coil inductance = 67.83 µH, made of email wire diameter = 1 mm, diameter of the cocker = …

Simple horizontal V antenna for NOAA weather satellites reception

Upward-horizontal-V-antenna

Modified  simple horizontal V antenna This antenna is little modified version of antenna  designed by Adam 9A4QV for noaa/METEOR  Weather sat reception. Adams antenna is based on a very simple linearly polarized dipole, which makes construction almost trivial. I tried his antenna and found that practical difficulties in finding choc block terminals. Chock block terminals are not strong enough …

Ribless Programming cable for Motorola GM360 radio

Ribless Programming cable for Motorola GM360 radio

This programming cable is intended to be used with the computer usb port for motorola GM360 radio. To program the Motorola GM360 using a ribless cable, you can use a cable that connects straight to the computer without needing any special box. One type of ribless cable is the RS232 to port RJ45 (front microphone …