Search results
Query: LF
Links: 638 | Categories: 7
-
Addresses the common challenge of constructing effective dual-band antennas for VHF/UHF operations, specifically detailing a J-pole design. It covers the theoretical underpinnings, including calculations for quarter-wavelength radiator and stub sections, accounting for velocity factor and design frequency. The resource provides practical construction guidance using readily available materials like TV twin lead and coaxial cable, culminating in an antenna with a total length of approximately 52 inches. Performance metrics are presented, showing a measured SWR of 1.7:1 or better across most of the 2-meter band and less than 2:1 across the 70-cm band. These SWR measurements, referenced to 50-ohm impedance, were taken at the transmitter end of the feed line. The article also touches upon the necessity of a balun for proper impedance matching between the balanced J-pole and unbalanced coaxial feed line, suggesting a split-core cylindrical ferrite for this purpose.
-
This article published on QEX details measurements of tree conductivity and permittivity at HF frequencies, addressing a long-debated topic in amateur radio. N6LF conducted experimental impedance measurements on Douglas fir and maple trees using a vector network analyzer with rings of nails inserted into tree trunks. Results showed that tree conductivity increases with frequency while relative permittivity decreases, similar to soil characteristics. Measured conductivity ranged from 0.06 to 0.4 S/m at 10 MHz, aligning with values used in previous research. These findings validate that NEC modeling can reliably estimate trees' substantial impact on HF antenna performance.
-
The Aziloop DF-72 antenna system provides 72 K9AY headings and 36 loop axes, allowing for rapid switching in 60 ms. It integrates a switchable 18 dB preamp, a 4-step attenuator (0-18 dB), and four 7-pole preselection filters to optimize receiver performance. The K9AY load is adjustable from 250 Ohm to 950 Ohm in 50 Ohm increments, offering flexibility for various receiving conditions. Control is managed via an intuitive Windows UI, supporting Local, Client, or Server modes, with headless remote operation possible through the built-in Ethernet Server. _Omni-Rig_ support facilitates auto-filter selection, PTT muting, and Rig-Sync functionality, enhancing integration with existing station setups. Designed by _GW4GTE_, the system utilizes a low visual impact, small-footprint antenna with orthogonal loops and an earth connection. It is suitable for general monitoring, co-channel station resolution, basic direction finding, and interference reduction across the VLF to HF spectrum.
-
The small receiving loop (SRL) is a versatile and efficient antenna that can be simply built from common materials. It is designed for reception on the MF and HF bands and may be put in a variety of shapes and sizes. Despite its unusual installation, the porch loop in this case operated admirably, producing several DX spots on the 40m band. The SRL can be a great option for people looking to boost their reception on the MF and LF bands.
-
This page is a discussion about impedance matching by Off Center Fed dipoles in the Wide L-form. When a vertical or horizontal dipole is bent into a 90 degree L-form, the impedance drops about half.
-
WaveTalkers asked AI itself what it thought. All of the content in the WaveTalkers AI Resources section is generated by AI. From the content to the code itself they will make every effort to showcase what works and what doesn't along the way.
-
open890 is a web-based UI for the Kenwood TS-890S amateur radio, and features good usability, clean design, and high-speed bandscope/audio scope displays, among other features not available either on the radio itself, or in the ARCP remote control software. It is currently only designed to interface with the TS-890 via a LAN (or wifi) connection, and not a USB/serial connection. It may work with the TS-990, as the command set is very similar, but is currently untested.
-
In this study, the author builds upon Muncy's research, demonstrating that radio-frequency current on cable shields affects audio systems through the "pin 1 problem" and shield-current-induced noise (SCIN). An enhanced equivalent circuit for ferrite chokes is proposed, addressing dimensional resonance and inductor self-resonance. Field tests confirm that chokes reduce interference across 500 kHz to 1,000 MHz. Guidelines for diagnosing and mitigating EMI from various sources are provided for product development and field installations.
-
This article presents a novel Top Loaded End-Fed Half-Wave (TLEFHW) antenna design for 20-meter ham radio operation. The antenna features a compact 14-foot vertical radiator with a capacitance hat configuration, eliminating the need for radials or ground systems. Using EZNEC modeling and field testing, the design achieves a 1.5:1 SWR across the 20m band with a 4.11 dBi gain. Key features include quick deployment, lightweight construction, and directional radiation pattern with 110-degree beamwidth. The design, while requiring a 45-foot footprint due to the top hat, offers an effective portable solution for amateur radio operators seeking a no-ground, no-tuner 20m antenna option.
-
his historical account traces the development of car radios from Marconi's mobile wireless telegraph station on a steam engine vehicle in 1901 to Motorola's iconic car radio models in the 1930s. It highlights key milestones such as Alfred Grebe's radio-telephone experiments on Long Island and the introduction of Marconi-Phone 8 radios by the Daimler Company in England. The narrative explores technological advancements, including the transition from TRF to Super-Heterodyne circuitry and the integration of push-button controls. The evolution from vacuum tubes to transistors and compact discs is also documented, showcasing the continuous innovation in automotive entertainment systems.
-
QSL Digest presents a curated collection of daily news and commentary relevant to the amateur radio community, drawing content from various sources. The platform features articles on diverse subjects such as **contesting**, new equipment releases, and current propagation conditions, alongside updates on satellite operations and the activities of prominent amateur radio operators. It functions as a community-driven hub, aggregating information to keep hams informed about developments across the hobby. The site distinguishes itself by offering special features and a regular comic, adding unique elements to its news delivery. Content is sourced from the community itself, fostering a collaborative environment for information sharing. Each entry provides a concise summary and a direct link to the original source, allowing readers to quickly access detailed articles and stay current with the latest happenings in the amateur radio world.
-
The project details the construction of a small, portable **CW decoder** built around an Arduino Nano and an LM567 tone decoder circuit. It integrates an OLED display for output and is powered by a 1200 mAh Li-Po battery. The Arduino Nano is programmed with a modified version of the OST Morse Box firmware, originally based on Budd, WB7FHC's work, provided as a HEX file for flashing. The LM567 output connects to Arduino pin D2, while pins A6 and A7 are grounded due to the absence of potentiometers, simplifying the circuit. Standard I2C connections are used for the OLED: SDA to A4 and SCL to A5. The entire assembly, including the Arduino, OLED, and decoder circuit, is mounted on a perfboard to fit precisely within an old cassette tape box. This design emphasizes portability and compact form factor. Parameters for the decoder can be adjusted using a dedicated Windows Control program, offering flexibility in operation. The resource provides practical insights into adapting existing firmware for specific hardware constraints and achieving a self-contained, battery-powered **Morse code** decoding solution.
-
Learn about the ZRS QRP-808 kit system for hams from the 1980s. Discover the improved features of the QRP-808 compared to the QRP-805, including the electrical diagram and assembly instructions. Explore the nostalgic journey of building and tuning this iconic amateur radio station, as shared by experienced ham radio operators. See original photos and insights from enthusiasts like Janko S55WT and Mirko S52PC, offering a glimpse into the history of amateur radio technology. Access PDFs for detailed views and immerse yourself in the world of DIY radio equipment construction and tuning.
-
This page details the construction project of the 'Stone', a QRP double conversion superhet SSB transceiver for the 40m band. The project is based on a kit from Tim Walford, G3PCJ, and includes step-by-step instructions for building and testing each stage. The author has added enhancements such as a three digit frequency counter and an automatic gain control. The content is aimed at hams interested in DIY transceiver construction and includes technical details of the build process.
-
Outlines the essential steps for successfully activating a **Summits on the Air (SOTA)** peak, providing a structured approach for amateur radio operators participating in this popular award program. It details crucial pre-activation planning, including navigating the SOTA website, setting up a SOTA Data account, and consulting the **Association Reference Manual (ARM)** for specific regional rules and peak information. The guide also covers using mapping resources like adventureradio.de and lists ofjohn.com to identify suitable summits and check access conditions. The document emphasizes safety during the activation, advising operators to monitor weather, carry rain gear, and plan ample time for the ascent and descent. It specifies the **4-QSO minimum** requirement within the Activation Zone and recommends calling "CQ SOTA" on traditional QRP or VHF calling frequencies. The guide also suggests using local 2m FM repeaters for safety communications and spotting, while clarifying that repeater QSOs do not count for SOTA points. Post-activation activities include submitting logs to sotadata.org.uk, uploading trip reports to share experiences with future activators, and promoting SOTA participation on various reflectors. The guide highlights the program's appeal through its awards system for both activators and chasers, encouraging new participants in North America.
-
Demonstrates the construction of an active loop converter specifically designed for the Low Frequency (LF) bands, addressing common localized noise interference in LF reception. The design integrates a sharply tuned circuit and a tuned loop antenna, utilizing the loop as the sole tuned inductive element. By applying positive feedback, the converter significantly increases the loop's effective Q, achieving factors between 1000 and 2000, which sharpens tuning and reduces noise. The circuit employs an _NE602_ mixer stage, feeding its output to an HF receiver, with a crystal-locked local oscillator at 4 MHz. A 20-turn, 0.8-meter square loop antenna with 500 uH inductance is detailed, connected via 2 meters of figure 8 flex cable. The converter offers three selectable frequency bands: 195-490 kHz, 150-220 kHz (including the New Zealand amateur band), and 128-160 kHz (covering the European amateur band). Performance measurements indicate an effective 3dB bandwidth of approximately 100 to 200 hertz at 200 kHz. The article provides insights into component selection, including an _LF353_ op-amp and a trifilar wound transformer on a ferrite core. Sensitivity figures are presented, showing 7.5 uV of converted output per 1 uV/meter signal strength into a 50-ohm load, or 37.5 uV into an _FRG7_ receiver, highlighting its capability to extract weak signals from noise.
-
Detecting stray RF voltages on station grounds, chassis, and interconnecting cables is crucial for preventing program and hardware failures in the shack. This article details the construction and application of an LED RF V-probe, which offers significantly higher sensitivity compared to conventional neon lamp indicators. The probe leverages two specific properties of modern red LEDs: their ability to glow at microampere currents and their rectification capability at frequencies up to tens of megahertz. The design features a simple circuit with two LEDs, allowing for indication of both positive and negative RF voltage half-waves. The minimum detectable RF voltage is approximately 2 V, a substantial improvement over the 40-60 V threshold of neon bulbs. The resource illustrates the probe's physical construction on a PCB and provides a direct comparison demonstrating its superior sensitivity in detecting RF fields near a coil. Two operational modes are described: a non-contact mode for high RF voltages (above 15-20 V) and a direct-contact mode for measuring lower RF voltages, with a safety caution for the latter. Practical examples show the probe's use in analyzing RF voltage distribution across a radio station setup at 1.84 MHz and 24.9 MHz, revealing insights into common-mode current issues and the effectiveness of mitigation strategies like adding radials.
-
This project outlines a simple Lead Acid/SLA battery monitor, designed to alert users when battery voltage falls below 10.6V. The monitor, based on a PIC16F1827 microcontroller, checks the voltage of up to five batteries and triggers an alarm if any drop too low. The system operates in various modes, including self-test, monitoring, and alarm. This updated version improves upon the original 1999 design, offering a more modern microcontroller and extended functionality for workshop use, with minimal impact on battery charge.
-
KISS703 is a 703 Hz narrowband digital mode for amateur radio, designed for simple, low-power operation without computers. A 500 Hz pilot tone ensures frequency alignment, replaced by unique tones for 37 symbols (letters, numbers, space). Built from common discrete components, it draws about 40 mA at 12 V, ideal for SOTA/IOTA use. The receiver uses amplification, wave shaping, and a pulse-counting frequency meter for manual decoding via a calibrated meter. Transmitter and receiver calibration involves marking meter positions for each tone, enabling fully self-contained messaging with minimal hardware in portable or fixed operations.
-
Investigates the performance characteristics of the _AAA-1_ active loop antenna across Very Low Frequency (VLF) and Low Frequency (LF) bands. It details the antenna's frequency response, explaining how a small loop with a low input resistance trans-impedance amplifier maintains a flat frequency response to electromagnetic field intensity E. The document illustrates current source and Thevenen equivalent circuit models for small loops, emphasizing the transition between these models based on frequency and load impedance. Measurement setups for both high frequency and VLF/LF responses are presented with diagrams, including methods for simulating current and voltage sources. The analysis includes normalized plots of the _AAA-1_'s frequency response for three distinct loop inductances, derived from measurements using a _Perseus SDR_ at 1 kHz bandwidth. It provides calculations for the noise floor at VLF/LF frequencies, comparing ambient noise levels with the antenna's internal noise floor. The resource also documents practical reception experiments in a semi-urban environment, showcasing successful reception of time transmitters like _MSF_ at 60 KHz and _SAQ_ at 17.2 KHz, along with various navy digital transmissions and Russian Alfa beacons.
-
The article "Icom IC7300 RTC Fix" details the meticulous repair of an Icom IC-7300's faulty real-time clock (RTC). The author and a friend, Nacho, discovered the RTC was gaining an unacceptable 11 seconds per day. Investigations revealed the Seiko Epson RX8803LC RTC was far outside its specified stability. Despite replacing the RTC and a burned pullup resistor, the transceiver still malfunctioned, leading to the replacement of the processor. Post-repair, the clock's accuracy improved significantly, now gaining only 1.4 seconds per month. This narrative underscores the complexities of electronic repairs and the satisfaction of resolving intricate issues.
-
The Zeppelin antenna, a J-type design, is presented as a two-band HF dipole, offering independent operation on harmonically related frequencies. This resource details its electrical configuration, comprising a half-wave radiator end-fed by a quarter-wave matching section, and explores its historical evolution from early Zeppelin airship applications to modern amateur radio use. The article specifically examines how a Zepp antenna tuned to 28.4 MHz (10 meters) exhibits a harmonic relationship with 15.4 MHz (20 meters), noting a frequency ratio of approximately 1.84:1, which deviates from a perfect 2:1 due to factors like elevation, wire separation, velocity factor, and end-effect. Antenna modeling results, including SWR sweeps at 28.4 MHz (1.1 SWR) and 15.4 MHz (1.6 SWR), are provided through Graph 1 and Graph 2, illustrating the antenna's performance across these bands. Current distribution patterns for both the 28.4 MHz (second harmonic) and 15.4 MHz (first harmonic) operations are visually represented in Figure 2 and Figure 3, respectively. The author also includes a 4NEC2 model's "Symbol Conversion file" definitions and calculated #14 wire dimensions for achieving resonance at 28.4 MHz, with the antenna positioned at a height of 33 feet. The discussion further highlights the antenna's versatility, suggesting its potential as a single-band, center-fed, 15.4 MHz half-wave folded end dipole when fed at a specific low current point. This analysis provides practical insights into constructing and optimizing a multi-band Zepp antenna for HF operations, emphasizing its unique harmonic characteristics and physical compactness.
-
MyWaveRecorder is a lightweight utility designed to capture and save any audio played on your computer. Whether it’s sounds generated by programs like CW_PLAYER, WX_PLAYER, MyWaveRecorder itself, your microphone, your sound card, or even streaming audio from the internet, this tool records them all with a single click.
-
Provides access to a robust DX cluster node, G6NHU-2, running DX Spider software, which facilitates real-time amateur radio contact spotting across HF bands. This service is engineered for high reliability and low latency, ensuring rapid dissemination of DX spots from a global network of interconnected nodes. It features multiple redundant links to prevent data loss and maintain continuous operation, even if individual connections drop. The cluster integrates directly with the Reverse Beacon Network (RBN), allowing users to enable or disable skimmer spots for specific modes like CW, RTTY, FT8, and FT4. It also offers an extensive one-year spot history, significantly longer than most other DX clusters, which typically retain only a month of data. The node supports various lookup commands for callsign information, beam headings, QSL routing, and FCC database lookups, enhancing operational efficiency for DXers and contesters. Additionally, it permits self-spotting, a feature increasingly relevant in modern contests, and provides detailed instructions for connecting popular logging software such as N1MM+, HamRadioDeluxe, MacLoggerDX, LOG4OM2, Logger32, and N3FJP's Amateur Contact Log.
-
Constructing a **J-Pole antenna** from 450 Ohm ladder line for 2-meter (144 MHz) and 70-centimeter (440 MHz) operation involves specific calculations and assembly steps. The design, based on an earlier KD6GLF concept using 300 Ohm twinlead, features a ¾ wavelength radiator and a ¼ wavelength matching stub, functioning as an end-fed half-wave antenna without requiring ground radials. It offers a gain of 2.4 dB over isotropic. The resource provides the formulas for determining the lengths of the ¾ wave radiator and ¼ wave stub, incorporating a velocity factor of 91% for 450 Ohm ladder line. For 146 MHz, the radiator measures 55 3/16 inches and the stub 18 3/8 inches. Construction details include cutting a 57¾-inch piece of ladder line, stripping 4 inches from one end, and attaching a 24-inch section of RG58 or RG8X coax with a 3-5 turn RF choke. SWR adjustment is achieved by sliding a shorting bar or by incrementally trimming the elements at a 1:3 ratio (stub to radiator). The goal is a 1:1.1 SWR at 146 MHz, which typically yields 1:1.2 at 446 MHz. The article also discusses power handling, noting that while 10-15 watts is fine, 50 watts may increase SWR to 1:2.1, and advises keeping the antenna away from other objects to prevent coupling and SWR degradation.
-
This page provides a detailed guide on the J-pole antenna, an end-fed half-wave antenna matched to the feedline by a quarter-wave transmission line stub. It covers the characteristics, construction materials, feeding options, and mounting considerations for optimal performance. The information is useful for hams or amateur radio operators looking to build and set up a J-pole antenna for improved transmission and reception.
-
Enables digital radio transceivers to function as versatile data communication nodes, supporting applications like _Reticulum_ networking, messaging with Sideband, and acting as a LoRa-based KISS-compatible amateur radio TNC. This firmware transforms off-the-shelf development boards into powerful, long-range data radios, facilitating robust communication over significant distances, potentially achieving **hundreds of kilometers** with optimal setups. It supports a range of hardware, including unsigned.io's Handheld RNodes (v2.x and v1.x), LilyGO T-Beam v1.1, LilyGO LoRa32 (v2.0, v2.1), and Heltec LoRa32 v2 devices. Compatibility extends to transceiver modules utilizing Semtech SX1276, SX1278, SX1262, SX1268, and SX1280 chips, provided they have an SPI interface and exposed interrupt pins. Installation is streamlined via the `rnodeconf` utility, part of the `rns` package, simplifying the flashing process for users. The project operates under the GNU General Public License v3.0, promoting open development and user freedom. It encourages community involvement in building and deploying RNodes for various purposes, from personal communication to establishing resilient, decentralized networks. The firmware's design emphasizes flexibility, allowing for diverse configurations to suit specific operational requirements.
-
This page discusses the construction and use of a low pass filter for MF/LF reception, specifically for the 630 meter and 2200 meter bands. The author, KA7OEI, shares technical insights and practical advice related to amateur radio, with a focus on improving reception in the low-frequency bands. This resource is useful for hams interested in building their own filters to enhance their MF/LF reception capabilities.
-
Open Signal, a software application for Windows 10/11 and 64-bit Linux, facilitates the transmission of color pictures, photo files, and text over HF and VHF amateur radio bands. It integrates its own error-corrected OFDM digital picture mode, delivering pixel-exact images in under a minute, with classic analog SSTV across six families: Martin, Scottie, Robot, Wraase, PD, and MMSSTV's MP/MR, featuring automatic VIS mode detection on receive. The application offers four distinct sending methods, including byte-exact JPEG transfer, a hybrid mode utilizing internet for full quality with a short RF link, and its proprietary digital waveform. This self-contained executable eliminates the need for external software like FLDIGI, Hamlib, or virtual audio cables, simplifying setup. It includes a self-filling logbook that integrates with Wavelog/Cloudlog, eQSL, and provides UDP ADIF broadcast. Built-in spotting features include PSK Reporter, DX cluster announcements, and APRS-IS position beacons. The receive-only version is permanently free, while a full license, enabling transmit capabilities and access to the live network, is available for an annual or lifetime fee. The software is actively maintained, unlike EasyPal, which has not seen updates since 2014.
-
The W6PQL 23cm Beacon Project describes a **1296 MHz** beacon designed for microwave propagation studies and equipment testing, capable of 30 watts output. It utilizes a PIC 16F628A microcontroller to generate CW and FSK keying for a crystal oscillator, followed by a series of frequency doublers and triplers to reach the target frequency. The final power amplification stage employs a Mitsubishi M57762 module, providing a robust 10-watt RF output. The design emphasizes stability and reliability for continuous operation, with the microcontroller code, written in assembly, provided for customization of the beacon's callsign and message. Originally located in CM97am and aimed at 140 true, the beacon used four 4-foot Yagis stacked vertically for a total ERP of 3kW. The article includes schematics, parts lists, and construction notes to guide builders, along with antenna pattern measurements. Although the beacon itself is no longer in service as of August 2010, the detailed documentation remains a valuable reference for amateur radio operators interested in building similar **microwave** projects or understanding beacon operation.
-
HamDaily presents a **real-time dashboard** for amateur radio operators, integrating live propagation data, current space weather conditions, and a continuously updated stream of DX, POTA, and SOTA spots. The platform also curates news headlines and articles from more than 16 distinct amateur radio sources, offering a centralized hub for daily information. Beyond its real-time data feeds, HamDaily includes practical tools such as practice exams for licensing, a Morse code trainer, a repeater finder, and satellite pass predictions, catering to both active operators and those preparing for their licenses. The resource distinguishes itself by fusing diverse data streams into a single, cohesive interface, allowing operators to quickly assess band openings and relevant activity. The "Today's Roundup" section provides a daily digest of featured articles, ranging from technical insights like "My one-day Tech class 'bag of tricks'" by KB6NU to operational accounts such as QRPer's "Eight Parks, One Missing Mast, and the Midnight Sun: A CW-Only POTA Trek." This aggregation of content, combined with **live band data** and Kp index readings, offers a comprehensive operational awareness tool for the ham radio community.
-
The Alfa Alfa (AA) DX Group, established on March 1, 1974, in the Netherlands, is presented as the pioneering Dutch 27mc DX group. It details the group's historical significance, particularly its revolutionary use of the '000' club callsign (19AA000) which influenced international 11-meter group callsign structures. The resource outlines the group's re-establishment in 2024, inviting new active CB operators and _Short Wave Listeners_ (SWL) to join its ranks, emphasizing a free worldwide membership model. Membership requirements are specified, focusing on active participation with an assigned AA callsign. The group provides QSL card management services, with options for direct QSL requests requiring **3 USD** and a Self-Addressed Envelope, or **4 USD** via PayPal for expenses. It also mentions upcoming initiatives like an _AA DX Contest_ and an award program, with sections for certificates and plaques currently under construction. The site also lists useful CB resources, including an 11M DX Cluster and an 11M Callsign Database, and provides contact information for the founder, 19AA001 Mr. Theo, and the Worldwide QSL Manager, 178AA001 Mr. Emil, based in Bulgaria.
-
HamHAW (Ham Health and Welfare) is a pioneering platform that bridges the gap between emergency communication and community welfare. By leveraging the extensive ham radio network, we help locate missing persons and coordinate welfare checks during disasters when traditional communication infrastructure fails. Hamhaw mission is to provide emergency communications support to the public so those inside an emergency area can communicate their status and needs to authorities and the public at large.
-
AA DX Group was founded in March 1, 1974 in The Netherlands. Our members was more than 10000 from all over the World. Because during the years many of our members became "Silent Keys" or they are not active on the air anymore, we deceide to make new fresh group and to delete all old database. So, we are the new - old Alfa Alfa DX Group and you are welcome to be our member. We make avaiable all Alfa Alfa numbers for new and active CB members and SWL ( Shrot Wave Listeners ). Alfa Alfa World Wide DX Radio group is looking or ACTIVE CB Operators and SWL stations ! The New AADX team in in 2024 Main base in 178AA000 178AADX000 in Belgaria
-
We are a non-profit amateur ham radio association located in the rural Lakes Region of New Hampshire. We actively promote 2 way radio, also known as ham radio. Our members are friendly and knowledgeable. If you are a first time visitor and are curious about this great hobby, we provide testing for ham licenses, have fun get-togethers, and are ARES affiliated for emergency communications. We also are home to 6 repeaters. Three are located on Bennett Hill in Ossipee, one on Mt. Rowe in Gilford and two on New Durham Ridge, New Hampshire.
-
108 Alfa Tango 101 - My personal CB Radio and 11m DX homepage.
-
Demonstrates _FreeDV RADE_, an open-source digital voice mode for HF, which combines machine learning with classical Digital Signal Processing (DSP) to achieve improved speech quality and spectral efficiency. Released in June 2025 by ARDC grantee FreeDV, RADE operates at Signal-to-Noise Ratios (SNRs) as low as -2 dB and occupies approximately 1.5 kHz of bandwidth, half that of a typical SSB signal, while transmitting about 8 kHz of voice audio. The mode also features an optimized Peak-to-Average Power Ratio (PAPR) for efficient power amplifier use, reducing heat and consumption. Users, such as _VK3TPM_, report significantly improved listening ease compared to analog modes, particularly in high HF noise environments, making it easier to conduct nets across various Australian states. The mode's integration into popular radios like the _FlexRadio 6000_ series allows direct operation without external computers. A C library for RADE is available, facilitating broader integration into other radios and SDR programs, with development continuing on FreeDV RADE v2 to further narrow bandwidth below 1 kHz.
-
For amateur radio operators seeking resilient, off-grid communication, the _MeshCom_ firmware provides a robust solution for text-based messaging over a mesh network. Utilizing LoRa modulation and the APRS protocol, this firmware is designed for low-energy consumption and cost-effective hardware, primarily operating in the 70cm band. Nodes, identified by amateur radio callsigns, can send short text messages to all participants or directly to specific callsigns, functioning as repeaters to extend network reach. The system supports automatic status and position messages, with optional sensor data for WX-Data and Telemetry. MeshCom nodes can be configured as gateways to HAMNET or the internet, enhancing connectivity options. The project emphasizes a self-building and self-healing mesh network architecture, crucial for emergency communication scenarios. Operating frequencies include **433.175 MHz** (EU, USA, Africa), 439.9125 MHz (UK), and 433.925 MHz (Norway). The firmware is compatible with hardware platforms such as ESP32/LoRa modules, RAK-WISBLOCK, and ESP32-DEV4/E22-LoRa, offering a flexible deployment for various amateur radio applications.