Radio Communication Technology Blog

NanoVNA Test Jig: A Practical Guide for Accurate RF Measurements : Learn how a NanoVNA test jig improves RF measurement accuracy. Detailed guide covering applications, crystal testing, filter evaluation, and RF prototyping etc.

Maximize your FM radio signal with the power of a Slim Jim Antenna ! 📡🎶 If you are looking for a high-performance, budget-friendly DIY project to improve your 88–108 MHz reception or broadcast range, the Slim Jim is a game-changer. Unlike standard dipoles, this end-fed folded dipole offers a lower angle of radiation, directing more energy toward the horizon where you actually need it. Why choose the Slim Jim? High Gain: Significant improvement over a standard ground plane antenna. Low Noise: Integrated matching section helps reduce man-made interference for a cleaner signal. Weatherproof & Portable: Easily house your build in a PVC pipe to protect it from the elements. Custom Tunable: Precision measurements for 88, 92, 96, 100, 104, and 108 MHz. Whether you are a DXer trying to catch distant stations or a local broadcaster optimizing your setup, this guide provides the exact dimensions and wiring steps to get the job done. 🛠️📻 Check out the full technical breakdown, wiring ...

Log audio Compressor Circuit for Smooth Natural Compression

Build Your Own Hidden Transmitter Hunter RF Sniffer Circuit : Discover how to build a hidden transmitter hunter using a simple RF snifter circuit. Ideal for transmitter hunts and bug tracking with minimal components.

Log audio Compressor Circuit for Smooth Natural Compression : Build a log audio compressor circuit using BC549 transistors and diodes for smooth signal compression over a 60 dB range. Ideal for mic-level signals.

Integrating JTDX with sBitX for Advanced FT8 Operation : Learn how to integrate JTDX with sBitX v3 for advanced FT8 operation, including PSK Reporter spotting, eQSL logging, and superior weak-signal decoding.

The Ultimate DIY Guide to Setting Up a GOES-R Series Satellite Receiver for High-Resolution Weather Imagery : Introduction to GOES-R The GOES-R series (Geostationary Operational Environmental Satellite-R) represents NOAA's latest generation of weather satellites, including GOES-16 (GOES East) and GOES-17/18 (GOES West). These satellites transmit high-resolution weather imagery and atmospheric data that can be received by amateur radio operators and weather enthusiasts using relatively affordable equipment. Key Benefits: Real-time weather imagery updated

Terminated Mini Loop Antenna : Small Space Ham Radio Antenna : The Terminated mini loop antenna is a relatively simple antenna to construct. It can provide the user with wide/multi band access

Mini-Radio Firmware V3 Adds RTTY/CW Decoding and EiBi Integration : Mini-Radio Firmware V3 by H. J. Berndt introduces built-in RTTY and CW decoding along with EiBi schedule integration, enhancing SI4735-based portable receivers.

The Ultimate DIY Guide to Setting Up a GOES-R Series Satellite Receiver for High-Resolution Weather Imagery : Introduction to GOES-R The GOES-R series (Geostationary Operational Environmental Satellite-R) represents NOAA's latest generation of weather satellites, including GOES-16 (GOES East) and GOES-17/18 (GOES West). These satellites transmit high-resolution weather imagery and atmospheric data that can be received by amateur radio operators and weather enthusiasts using relatively affordable equipment. Key Benefits: Real-time weather imagery updated

sBitx v3: The Linux SDR That Refuses to Be Boring : In-depth sBitx v3 review with real-world operation, specs, strengths, and flaws. A Linux-based HF SDR radio built for experimentation.

MagSafe Breadboard Turns the iPhone into a Portable Electronics Prototyping Lab : MagSafe Breadboard is an innovative concept that attaches to an iPhone and turns it into a portable prototyping lab. Ideal for learning and DIY electronics

RW4HFN Balcony Antenna for the 20-Meter Band : Discover the RW4HFN balcony antenna design for the 20-meter amateur radio band—ideal for limited spaces. Includes schematic, dimensions, and inductance values

NE555 based Microphone amplifier : IC NE555 is an IC that is well known among hobbyists as an IC for timers, and can be used to form of multivibrator circuits.NE555 based Microphone amplifier

Microphone Preamplifier with Audio Peak Limiter : Build a simple microphone preamplifier with audio limiter using 2N3904 transistors and 1N34 diodes. Ideal for ham radio, DIY audio, or voice processing

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.

Microphone compressor using two transistors : Microphone compressor is a useful tool that can help you to achieve more consistent and polished sound. By reducing gain of the loudest parts of your signal,

Simple CW 74HC240 Transmitter using buffer IC : This is a simple but effective CW 74HC240 transmitter design using a octal buffer IC 74HC240 as the main component, operates at 7.023 MHz .

RA9SUS Simple Loop Antenna covering 14–30 MHz : Detailed explanation of the RA9SUS simple loop antenna covering 14–30 MHz, with tuning method, construction tips, and real-world HF performance. In amateur radio, antennas often become a compromise between available space and desired performance. The  RA9SUS simple loop antenna  is a refreshing exception. Designed for operation from  14 to 30 MHz , this compact HF loop antenna delivers surprisingly reliable results while occupying very little physical space. For operators restricted to balconies, terraces, or indoor installations, this design opens the door to serious HF operation without large wire runs or ground systems.

ZBitx: The Pocket SDR That’s Redefining Portable QRP : The ZBitx is the latest entry in BITX family from HF Signals, lab of Ashhar Farhan VU2ESE. n all-band, all-mode SDR transceiver that actually fits in a pocket.

The Ultimate DIY Guide to Setting Up a GOES-R Series Satellite Receiver for High-Resolution Weather Imagery : Introduction to GOES-R The GOES-R series (Geostationary Operational Environmental Satellite-R) represents NOAA's latest generation of weather satellites, including GOES-16 (GOES East) and GOES-17/18 (GOES West). These satellites transmit high-resolution weather imagery and atmospheric data that can be received by amateur radio operators and weather enthusiasts using relatively affordable equipment. Key Benefits: Real-time weather imagery updated

How to Receive Stunning Weather Images from Meteor-M2 Satellites : Learn to capture stunning weather images from Meteor-M2 satellites with this step-by-step LRPT setup guide using RTL-SDR and SatDump.

Audio compressor for microphone : This circuit diagram illustrates an audio compressor for microphone signals. Its primary job is to even out the volume of your voice, making soft sounds louder and loud sounds quieter, resulting in a more consistent and professional audio output. This is incredibly useful for podcasts, voiceovers, amateur radio, or any application where microphone levels can fluctuate.

Separating Signal from Static: Common Myths and Facts About Radio Antennas : We debunk the biggest myths about radio antennas, SWR, resonance, and gain for HF, VHF, and UHF systems. Learn the facts about antenna efficiency.

Audio Clipper Circuit Using BC547 and 1N914 Diodes : Build a simple audio clipper circuit using a BC547 transistor and 1N914 diodes. Ideal for speech compression in PA and transmitter systems.

ATS20 Radio Receiver: Comprehensive Review – Small Package & Big Performance : The ATS20 radio receiver has emerged as a surprisingly capable compact multi-band radio that punches well above its weight class

Quansheng UV-K5/UV-K6 Radios Get New MCU, Firmware Risks : Quansheng UV-K5 & UV-K6 radios now feature new PY32F030 MCU instead of the STM32F030, creating custom firmware compatibility issues and potential bricking risks

Exploring the MSI.SDR: A Low-Cost Gateway into Software Defined Radio : The MSI.SDR is a broadband SDR receiver that covers frequencies from 10 kHz to 2 GHz, making it suitable for a wide range of applications.

ATS MINI ESP32-S3 SI4732 Pocket Radio DSP Receiver – Technical Analysis : The ATS MINI RADIO - ESP32 Pocket Radio DSP Receiver represents sophisticated fusion of modern microcontroller and advanced DSP for radio reception.

Exploring the LILYGO T-Embed SI4732 Radio Receiver : The LILYGO T-Embed SI4732 is a compact, feature-rich development board that combines the power of the ESP32-S3 microcontroller with the versatile SI4732

HydraSDR RFOne: A New Contender in the SDR Market Challenges the Airspy R2 : The HydraSDR RFOne is a USB software-defined radio receiver designed for professionals, researchers, and radio enthusiasts. as a direct competitor to Airspy R2.

Building a Andy 2E1TAP’s Shortened 40-Meter Delta Loop : Full-size Delta Loops for the 40-meter band normally require around 42 meters of wire—often impossible for operators with limited space. To overcome this challenge, Andy (2E1TAP) documented his attempt at constructing a space-efficient, shortened 40-meter Delta Loop. His build, shared through a detailed video and photos, shows that even a newcomer to loop antennas, coil winding, and balun construction can successfully create an effective HF antenna with basic tools and patience.

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.

Quansheng UV-K5/UV-K6 Radios Get New MCU, Firmware Risks : Quansheng UV-K5 & UV-K6 radios now feature new PY32F030 MCU instead of the STM32F030, creating custom firmware compatibility issues and potential bricking risks

Terminated End Fed Vee Antenna (TEFV) : Terminated End Fed V Antenna (TEFV) - It Is a travelling wave antenna, which has a constant current distribution along its length.

Circuits – 7 Mhz 5 Watts CW Transmitter : This classic 7 MHz CW Transmitter circuit demonstrates how effective amateur radio equipment can be built with minimal components

Shortened Vertical Antenna for the 80-Meter Band (UR0GT Design) : Compact 4-meter 80-meter band shortened vertical antenna by UR0GT explained—design, loading coil, tuning details, and coax-based matching network.

Building an FT8 Digital Interface – Dive into Digital Modes : This blog post examines a well-designed FT8 digital interface circuit that provides both audio coupling and PTT (Push-to-Talk) control.

Terminated Antennas for HF Ham Radio: A Technical Guide : Terminated antennas represent a specialized class of HF antenna systems that incorporate resistive termination to achieve specific performance characteristics.

Simple CW 74HC240 Transmitter using buffer IC : This is a simple but effective CW 74HC240 transmitter design using a octal buffer IC 74HC240 as the main component, operates at 7.023 MHz .

Exploring the LILYGO T-Embed SI4732 Radio Receiver : The LILYGO T-Embed SI4732 is a compact, feature-rich development board that combines the power of the ESP32-S3 microcontroller with the versatile SI4732

Building Steve Quest’s Simple AM Transmitter : Steve Quest AM Transmitter, a popular and relatively straightforward design for hobbyists. It is a is fun to build and teaches basic radio principles

A Beginner’s Guide to ATS20+ Firmware Flashing : ATS20+ Firmware flashing r refers to the process of replacing or updating the internal software (firmware) that controls the receiver's operations

Tiny FM Transmitter with Just a Few Easy-to-Find Components : This Tiny FM Transmitter is a great example of how powerful a simple circuit can be. With just a handful of components, you can transmit audio signals over FM frequencies. Whether you’re an electronics hobbyist or a beginner experimenting with RF circuits, this project is an easy and exciting place to start.

Build Your Own 90MHz Crystal Controlled FM Transmitter : A crystal controlled FM transmitter is a radio frequency (RF) circuit that uses a quartz crystal oscillator to generate a stable, precise frequency for FM radio transmission. Unlike simple LC oscillator circuits, crystal-controlled transmitters offer superior frequency stability and accuracy, making them ideal for applications requiring consistent performance.

Video – KTWR DRM Transmission Reception : KTWR DRM Transmission Reception Day - 16.01.2022,sunday, 4.00PM IST,10.30 UTC 15200 kHz DRM Mode Location - Krishnagiri 635108 Equipment - MSI.SDR Dongle

DIY IRF510 AM Transmitter Circuit : This blog post dives into a detailed DIY IRF510 AM transmitter circuit using the IRF510 MOSFET, perfect for radio enthusiasts and electronics hobbyists.

How to Build a 3-Watt AM Radio Transmitter : A 3-watt AM Radio transmitter circuit is a medium-power radio frequency circuit capable of broadcasting audio signals over the AM radio band.

LM324 microphone speech compressor : The circuit shown is a microphone speech compressor built LM324.This circuit exhibits gain, and adjusts that gain to maintain a constant amplitude output signal

Circuits – Pippin QRP Transmitter : This pippin QRP transmitter is basically a conventional colpitts type crystal oscillator with output taken from a low value collector load resistor

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.

Dynamic speech 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

Audio compressor for microphone : audio compressor for microphone even out volume of voice, making soft sounds louder and loud sounds quieter, resulting a more consistent and professional audio.

Simple audio compressor for SSB HF Radio rigs : Simple audio compressor is a device that reduces the dynamic range of the audio signal. It makes the loud parts of signal quieter and quiet parts of the signal louder.

Shortened Inverted V Antenna for 80 Meters (3.700 MHz) : This Shortened Inverted V antenna offers excellent radiation characteristics, low SWR when tuned properly, and stable performance for both local NVIS communication and medium-distance regional contacts. It is an ideal solution for small gardens, rooftops, terraces and portable HF operations.

Multi Band Capacitor Loaded Shortened Dipole Antenna : Learn how to build compact multi-band HF shortened dipole antenna using a center-mounted adjustable capacitor. Includes frequency-capacitance chart, dimensions

Loaded Loop Antenna – A Practical Balcony HF Solution : The Loaded Loop Antenna is a clever HF antenna design ideal for radio amateurs with limited space—particularly those operating from apartments or small homes. Originally installed along the perimeter of a brick-house balcony, this antenna demonstrates how thoughtful engineering and creative loading can produce surprisingly effective multiband HF performance. The circuit diagram below  shows the construction of a multiband loop antenna that uses an external load and a ferrite core transformer for impedance matching

Build Your Own Indoor Antenna for 7 MHz HF Band : If you’re a ham radio operator working with limited space, building an indoor antenna for 7 MHz can be a game-changer. Whether you’re in an apartment, a shared living space, or simply want a stealthy setup, this compact antenna design from F6CYV offers an effective solution without compromising performance.

GM4JMU Shortened Dipole Antenna: Compact Performance for HF Bands : This design is a classic example of a coil-loaded dipole, a method that uses lumped-constant inductors to electrically resonate a physically short antenna. By inserting these coils symmetrically into the antenna’s radiating elements, we introduce the necessary inductance to tune the system to the 40-meter band, even though the overall wire length is significantly reduced.

🚀 Just discovered a great DIY mod for my HF rig! The SSM2167 microphone pre-amp/compression board supercharges audio clarity on a uBITx transceiver — boosting mic gain, compressing dynamic range, and gating noise for cleaner, more powerful transmissions. 🔊 If you’ve ever struggled with weak mic output or noisy audio, this mod might be worth trying. 🌟 Check out the project here: https://vu3dxr.in/ssm2167-microphone-preamplifier-with-compression-for-ubitx-hf-transceiver/

Microphone Preamplifier with Audio Peak Limiter : Build a simple microphone preamplifier with audio limiter using 2N3904 transistors and 1N34 diodes. Ideal for ham radio, DIY audio, or voice processing

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

LARCSet kit – Most Affordable SSB/CW Transceiver Kit Released : Amateur radio enthusiasts have something exciting to celebrate this holiday season. The LARCSet, described as the world’s most inexpensive SSB/CW transceiver kit, is now available for purchase, with shipping beginning December 15th. LARCSet promises to rekindle the spirit of DIY in the ham-radio community by giving amateur radio enthusiasts a highly affordable, build-it-yourself radio — ideal for hobbyists, beginners, and tinkerers alike

DIY Wideband CMC Choke Using Steel Wool and RG-213 – A Simple Common-Mode Filter : Build a highly effective, wideband Common-Mode Current CMC choke using steel wool , RG-213 coax and a PVC tube. Learn how this resistive–absorptive choke

DIY 145 MHz Twin Delta Loop Antenna for Ham Radio Operators : A complete guide to building 145 MHz Twin Delta Loop antenna with dimensions, construction tips, feeding method, and performance advantages for VHF ham radio.

VHF Radio Receiver Antenna Amplifier Using MAX2633 – Simple Low-Noise RF Preamplifier Design : A complete guide to building a VHF radio receiver antenna amplifier using the MAX2633 low-noise RF preamplifier chip with schematic explanation

PhaseLatch Mini: An Affordable STM32-Based SDR Digitizer for Radio Experimenters : PhaseLatch Mini is an STM32-based SDR digitizer with dual 12-bit ADCs and 210 kS/s USB I/Q streaming for ham radio, HF/VHF listening, and SDR experimentation.

Square Loop Antenna for 144/430 MHz – Complete DIY Dual-Band Build Guide : Dual-band 144/430 MHz square loop antenna design with full dimensions, gain performance, materials, and DIY construction guide for VHF/UHF amateur radio.