VK3YE’s AGC circuit for ubitx

If you’re into homebrew radio or ham gear mods, here’s a neat find: a clever non-invasive AGC (Automatic Gain Control) circuit designed by VK3YE for the popular µBITX transceiver. Instead of modifying internal gain stages, this design uses a conventional audio AGC to drive an LED-LDR pair that automatically controls the audio level at the volume pot — helping tame strong signals, reduce distortion, and make listening more comfortable. It’s a simple but elegant way to add AGC where the stock uBITX doesn’t have one built in.

VK3YE’s AGC circuit for ubitx

VK3YE’s AGC circuit for ubitx uses a conventional audio AGC circuit which drives a LED that is optically coupled to a Light Dependent Resistor (LDR).

OpenSourceSDRLab PortaRF: The Next Evolution in Portable Software-Defined Radio

OpenSourceSDRLab PortaRF: The Next Evolution in Portable Software-Defined Radio: The OpenSourceSDRLab PortaRF is ultimate portable SDR, integrating the HackRF and PortaPack into one device. Explore its architecture and key features

Building Sovina 40M Class E CW Transmitter with BS170 MOSFETs

Building Sovina 40M Class E CW Transmitter with BS170 MOSFETs: High-efficiency 40M CW Class-E CW transmitter using BS170 MOSFETs and 74HC02. Complete circuit explanation and build notes for QRP hams.

Simple Receiver S-Meter Circuit for Your Radio

Simple Receiver S-Meter Circuit for Your Radio: build a receiver S-meter circuit using op-amp 741 and MPF102 FET. Perfect project for measuring signal strength in radio receivers.

Simple Speech Processor for Homebrew SSB Transceivers

Simple Speech Processor for Homebrew SSB Transceivers: A simple speech processor circuit for homebrew and QRP SSB transceivers, improving average talk power while maintaining clear and natural audio quality.

Good speech processing can make a dramatic difference to how a low-power SSB signal sounds on air. In homebrew and QRP SSB transceivers, transmitter audio is often clean but lacks average power, making signals sound weak during normal conversation. The compact Simple Speech Processor circuit shown here addresses that exact problem by increasing average talk power while preserving intelligibility and keeping distortion under control.

Housing the LARCSet: A Community-Designed 3D-Printed Enclosure

Housing the LARCSet: A Community-Designed 3D-Printed Enclosure: A detailed look at a 3D-printed enclosure for the LARCSet transceiver, featuring Peter Marks’ open-source design and real-world build photos by Michael VE3WMB.