VK4FUQ Optimized sloper antenna for 3.5Mhz

VK4FUQ Optimized sloper antenna for 3.5Mhz: VK4FUQ’s optimised sloper antenna for 3.5MHz.Good quality insulators are need at the top of the preferably non-conductive mast and at the end of the radial

G4RAW 80M QRP TAG CW Transmitter

G4RAW 80M QRP TAG CW Transmitter: G4RAW 80M QRP CW Transmitter, a popular, simple, and low-power (QRP) Continuous Wave (CW) transmitter design for the 80-meter amateur radio band.

Full Wave Loop Antenna for VHF, UHF & FM Radio Bands - Ready to Upgrade Your Radio Experience?

Check out our detailed guide with step-by-step instructions, calculations, and tips to build your own full-wave loop antenna!

👉 Read the full guide here: https://vu3dxr.in/full-wave-loop-antenna-for-vhf-uhf-fm-radio-bands/

Whether you're a seasoned radio operator or just getting started, this project is perfect for improving your station's performance. The best part? You'll learn valuable antenna theory along the way!

Building the LARCSet v3.0: Real-World Problems and Proven Fixes

Working on the LARCSET v3.0?

The Bitx20 community is full of brilliant minds, and many of us have faced similar challenges when putting this version together. I’ve compiled the most frequent problems and their proven solutions into one guide to help fellow builders.

From troubleshooting common errors to fine-tuning for better performance, this post is meant to be a "workbench companion" for your project.

Read more here: https://vu3dxr.in/building-the-larcset-v3-0-real-world-problems-and-proven-fixes-from-the-bitx20-community/

Let me know in the comments what your experience has been with the v3.0 so far! 73! 📻

#HamRadio #Homebrew #Bitx20 #RadioBuilder #VU3DXR

Simple series modulated AM QRP HF Transmitter

Check out this nifty beginner-friendly radio project: a Simple Series Modulated AM QRP HF Transmitter! It’s a low-power HF (high-frequency) transmitter using series modulation to send AM (amplitude modulated) audio signals — great if you’re into QRP (low-power) operation or want a hands-on build to learn RF basics. Perfect for homebrew enthusiasts and DIY radio builders alike. Dive into the details and schematic here: https://vu3dxr.in/simple-series-modulated-am-qrp-hf-transmitter/

Simple series modulated AM QRP HF Transmitter

Simple mic compressor using 3 Transistors for HF rigs

Simple mic compressor using 3 Transistors for HF rigs: Simple mic compressor using 3 Transistors is a effective, compressor circuit that can be used to improve the dynamic range of a microphone signal.

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).

Terminated End Fed Vee Antenna (TEFV)

It is a travelling wave antenna, which has a constant current distribution along its length. Antennas usually used by radio amateurs are resonant standing wave types like dipoles. It is built to a specific tuned length so that a standing wave is set up on the antenna element. This is efficient and narrow band, only works on the fundamental frequency. In a travelling wave antenna there are no standing waves on the antenna element as the power that would be reflected back from the end of the antenna is absorbed by the terminating resistor. Typically this is 25% of the power applied to the antenna.

The polarization of the TEFV ( Terminated End Fed V Antenna) is a mixture of vertical and horizontal that results in a kind of elliptical polarization. The main advantages of terminated end fed V antennas are its broadband nature and no tuner requirement. It provides a non-resonant antenna with exceptionally wide bandwidth, matching a 50 ohm coaxial cable transmission line with a VSWR of less than 2:1 from 1.8 MHz to 30 MHz.

The critical parts in TEFV antenna are 9:1 unun transformer and terminating resistor. Main problem was in constructing 9:1 Unun with correct size wire for windings. Winding with wrong wire size resulted in poor impedance transformation and high through loss. The resistor value should be 10% higher than the transformer output impedance. So for a 9:1 transformer (50 ohms to 450 ohms) the termination should be 500 ohms

Terminated End Fed Vee Antenna (TEFV):

G4RAW 80M QRP TAG CW Transmitter

G4RAW 80M QRP TAG CW Transmitter: G4RAW 80M QRP CW Transmitter, a popular, simple, and low-power (QRP) Continuous Wave (CW) transmitter design for the 80-meter amateur radio band.

Circuits – Sovina2 40M Class E Transmitter

Circuits – Sovina2 40M Class E Transmitter: Adaptation of Class E Transmitter for amateur radio application is very rare due to inherent difficulties in filter design till release of usdx transceivers.

Do it yourself Shortwave Transmitter circuit

Do it yourself Shortwave Transmitter circuit: This Shortwave transmitter circuit operates in shortwave HF band (6 MHz to15 MHz), and can be used for short range communication and for educational purposes.

40m Vertical Antenna: Compact Base-Loaded Design for Powerful HF Operation

The 40m vertical antenna is one of the most effective solutions for amateur radio operators who want strong DX performance without needing a full-size tower or large open yard. The 40-meter (7 MHz) HF band is prized for its reliability—offering both daytime regional communication and long-distance propagation at night. Yet, a full quarter-wave vertical requires around 10 meters of height, which can be impractical in residential areas.

That’s where a base-loaded 40m vertical antenna comes in—shortened to just 3.4 meters tall, it uses a coil at the base to achieve electrical resonance, allowing operators to enjoy 40m contacts from almost anywhere.A practical solution is a base-loaded vertical antenna, which uses an inductive loading coil at the base to achieve electrical resonance with a shorter radiator. The design shown above, originally credited to PY7NQ, is a compact yet efficient vertical antenna optimized for 40m HF operation.

This antenna is a base-loaded quarter-wave vertical for 40m, physically shortened to just 3.4 meters in height. The missing electrical length is compensated using a loading coil placed at the base.

40m Vertical Antenna: Compact Base-Loaded Design for Powerful HF Operation: 

Microphone compressor using LM1458

Check out this neat DIY project: a simple microphone compressor using the LM1458 op-amp—perfect for improving audio clarity and level consistency in amateur radio and audio projects. Great for homebrewers looking to add professional-sounding compression with minimal parts! 🎙️🔧
👉 https://vu3dxr.in/microphone-compressor-using-lm1458/

Fixing Poor Audio Quality in uBITX V6.1 HF Transceiver

Fixing Poor Audio Quality in uBITX V6.1 HF Transceiver: Recently i got a ubitx V6.1 transceiver at lamakan 2024 event and kept the same idle due to mqth commitments. Audio is too chirpy and unpleasant to hear.

Mighty Mite 5W Crystal Controlled QRP CW Transmitter

Discover more Amateur radio ham radio amateur radio Ham Transmitter transmitter radio Radio Mini rádió SI4732 Antenna

The Mighty Mite 40 Meter QRP CW Transmitter is a legendary low-power Morse code transmitter widely built by amateur radio operators for portable, minimalist, and educational operation. Operating around 7.023 MHz, this compact rig delivers approximately 5 watts RF output, making it ideal for QRP (low power) CW contacts on the 40-meter band.

Mighty Mite 5W Crystal Controlled QRP CW Transmitter

Build Your Own Multiband G5RV Antenna: A Classic Ham Radio Project

📡 Build your own classic Multiband G5RV Antenna and work multiple HF bands with a single wire setup! Simple, effective, and perfect for both beginners and seasoned hams. A great DIY project to boost your station and explore the airwaves. 🌍🔧
👉 Get the guide here: https://vu3dxr.in/build-your-own-multiband-g5rv-antenna-a-classic-ham-radio-project/

#HamRadio #G5RV #DIYantenna #AmateurRadio

Getting Started with FreeDV: A Beginner’s Guide to Digital Voice on Amateur Radio

Getting Started with FreeDV: A Beginner’s Guide to Digital Voice on Amateur Radio: Learn FreeDV digital voice for amateur radio. Beginner's guide covers setup, equipment, modes, and making your first contact using open-source software.

If you’re an amateur radio operator looking to explore digital voice modes beyond the usual FM repeaters, FreeDV offers an exciting opportunity to experiment with open-source digital communication. This guide will help you understand what FreeDV is, why it matters, and how to get started with this fascinating mode.

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.

Build a Powerful FM Radio Bug Transmitter

Build a Powerful FM Radio Bug Transmitter: guide on building a high-performance FM radio bug transmitter using BC547 and 2N3563 transistors. Explore RF electronics with this powerful 100MHz DIY project

LinHT SDR: Open-Source Linux-Based Handheld Software Defined Radio for Amateur Enthusiasts

LinHT SDR: Open-Source Linux-Based Handheld Software Defined Radio for Amateur Enthusiasts: LinHT SDR — a next-generation open-source, Linux-powered software defined transceiver designed for amateur radio, experimentation, flexibility, and hackability.

SSM2167 audio processor for Baofeng Mic enclosure

SSM2167 audio processor for Baofeng Mic enclosure: SSM2167 audio processor has a noise gate feature, which can be used to reduce noise in the audio signal. It is a useful addition to the uBitx SSB transceiver

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.

AM Radio into an SSB Receiver with a Simple BFO Circuit

AM Radio into an SSB Receiver with a Simple BFO Circuit: Learn how to use a 455 kHz ceramic resonator oscillator as a BFO for SSB reception in AM radios using proximity coupling - no modifications needed.

Build Your Own Commando AM Transmitter

Build Your Own Commando AM Transmitter: Build your own Commando AM Transmitter circuit with 3 transistors. Complete guide covers Q1 oscillator, Q2 buffer & Q3 amplifier stages.

The Poor-Man’s Transmitter: Building a Simple AM Radio Beacon from Vintage Electronics

The Poor-Man’s Transmitter: Building a Simple AM Radio Beacon from Vintage Electronics: The Poor-Man's Transmitter: Building a Simple AM Radio Beacon from Vintage Electronics, uses a clever arrangement of 4011 CMOS gates to create AM Radio Beacon

Microphone Pre-Compressor Circuit for SSB Transceivers

Microphone Pre-Compressor Circuit for SSB Transceivers: A practical microphone pre-compressor circuit for SSB transceivers using JFET and transistor stages. Improve transmit audio clarity and power in amateur radio

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.

Microphone Preamplifier with Diode Clipper for SSB Transceivers

Microphone Preamplifier with Diode Clipper for SSB Transceivers: Learn how to build high-performance microphone preamplifier featuring a diode clipper. This guide breaks down transistor stage and 1N914 limiting mechanism

Build Your Own 80M CW Transmitter from Scratch

Build Your Own 80M CW Transmitter from Scratch: Learn to build a simple 80M CW transmitter with crystal oscillator and parallel power amplifier. Complete circuit guide for amateur radio enthusiasts

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.