frequency modulation circuit | Next Electronics

The exciter board is based on an Arduino WSPR exciter. Plans are underway to create a more advanced stand-alone board using inexpensive Chinese DDS modules available from eBay. Currently, a DDS60 by AmQRP is being utilized. The output from this...

G3XTZ DF Rx Details

The receiver is constructed on a single-sided printed circuit board measuring 2 by 4.3 inches. Its compact size allows for installation in various enclosures, which should be adequately shielded. The main directional signal is captured by a tuned ferrite rod...

136 kHz QRSS receiver

For digital modes, the ideal receiver should be straightforward, featuring front-end selectivity, manually adjustable gain, and an IF filter. Many functionalities found in HF receivers can be implemented through software. In the collection of components, there was a surplus 1.4...

6-17 MHz SW reciever

Its very simple as It uses only 3 transistors 2n2222. The Coils can be altered to change the range of reception by lowering or highering the frequency. More: This circuit is a SW band receiver of range 6 to 17...

led rf signal meter

This RF Wave Absorption meter detects signals from 10 centimeters to 10 meters, depending on the setting of the 22 MegOhm gain adjustment potentiometer and the transmitter power. The RF signal is captured through germanium OA91 diodes and rectified to...

Desheng 119 700 High sensitivity l2-band stereo radio circuit diagram

The circuit diagram for the Desheng 119 700 type FM, TV sound, medium wave, and short wave high sensitivity L2-band stereo radio is presented below. The Desheng 119 700 type radio circuit is designed to receive various frequency bands including FM,...

Transmit Time Limiter

This circuit prevents transmissions that are too long, which can cause timeouts in repeaters and/or occupy a communication channel for an excessive duration. During transmission, the PTT (push-to-talk) line from the microphone is grounded, resulting in one input of the...

Modulation-monitor

Switching diodes are utilized to activate the neon lamps when negative-peak modulation reaches 50%, 60%, and 100%. To operate the circuit effectively, it is important to monitor the lamps. The 50% lamp should ideally be firing continuously, the 60% lamp...

wireless FM bug

This project is a miniature, VHF FM (wideband) Wireless Microphone transmitter of the type that are commonly referred to as BUG's. Note that "BUGS" are illegal but "Wide-Band Frequency Modulation Wireless Microphones" (WBFMWMs) are not, as so many people have...