Search results

A presentation of the Yagi Antennas, and other interesting tid-bits by Brian Mileshosky. The document provides an in-depth exploration of the Yagi-Uda antenna, detailing its historical development, design principles, and performance characteristics. Originally described in the 1920s, the Yagi antenna features a driven element and parasitic elements, including reflectors and directors, which collectively determine its behavior. The document highlights how element lengths, diameters, and spacing influence gain, impedance, and directivity. It also discusses the antenna's reciprocal nature and presents data on typical gain values for various element configurations. Additionally, the text covers practical considerations, such as the construction of a "Tape Measure Yagi" for amateur use, and touches on related antenna types like dipoles and their application in Near Vertical Incident Skywave (NVIS) communication.

The resource details the construction of a 433 MHz LoRa APRS iGate and a tracker, both built around _TTGO T-Beam v1.1_ microcontroller boards. Each board integrates an OLED screen, WiFi, GPS, and an SMA antenna connector, powered by an 18650 3.7 V lithium-ion battery or microUSB. The iGate operates on 433.775 MHz, with its status verifiable on aprs.fi, demonstrating practical implementation of LoRa-based APRS solutions. The methodology involves programming the modules using Visual Studio Code with the PlatformIO plugin. This process loads the necessary firmware and a JSON configuration file, which includes the operator's callsign and WiFi credentials for the iGate. The guide emphasizes the ease of programming and provides specific steps for configuration. Initial testing of the iGate and tracker, including smart beaconing configuration, is documented. The low power output of approximately 200 mW from the LoRa board's transmitter is noted, with suggestions for range extension through improved antennas or RF amplification. The author, N4MI, plans to deploy a higher-gain 70cm antenna for the iGate.

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.

The **CubeSat** standard, developed by California Polytechnic State University (Cal Poly) and Stanford University, facilitates frequent and affordable access to space for small satellites. This resource serves as a central hub for the CubeSat community, offering a comprehensive directory of active and past CubeSat projects, technical specifications, and educational materials. It details the standardized dimensions and mass constraints for these pico-satellites, which typically range from 1U (10x10x10 cm, 1.33 kg) to 12U configurations, enabling their deployment as secondary payloads on various launch vehicles. The site also provides insights into mission planning, component selection, and regulatory considerations for amateur radio satellite operations. Operators and developers can utilize the project directory to research existing CubeSat missions, understand their communication protocols, and identify potential collaboration opportunities. The platform's forum section allows for direct engagement with other enthusiasts and experts, fostering knowledge exchange on topics such as **AMSAT** frequency coordination, telemetry decoding, and ground station setup. This collaborative environment supports the development of new CubeSat projects, promoting innovation in amateur radio satellite communication and space exploration.

The resource details the use of LoRa for AX.25 packet radio and APRS, focusing on practical implementation. It specifies UK LoRa APRS frequency and modulation settings: **439.9125 MHz**, 125kHz bandwidth, SF12, and CR 4/5. The content provides a mini how-to for setting up an iGate using VS Code and _Platformio IDE_, with specific instructions for a Lilygo LoRa32 V2.1_1.6 board, including configuration for Wi-Fi, beaconing, and APRS-IS passcode. It also covers tracker setup using a Lilygo T-Beam Supreme, detailing firmware flashing and configuration for mobile operation. The guide differentiates LoRa APRS from traditional connected-mode packet radio, explaining why common LoRa APRS firmware is unsuitable for full AX.25 packet due to its TNC2-style payload structure. It explores alternative solutions for true LoRa packet radio, such as using an _RNode_ TNC or Raspberry Pi LoRa TNCs, and provides commands for RNode firmware installation and configuration for serial KISS operation. The resource also touches upon licensing requirements for unattended Digipeaters in the UK, noting the need for ETCC coordination and MB7Uxx callsigns.

The resource provides a technical installation guide for _MeshCom 4.0_, an amateur radio mesh networking project utilizing LoRa hardware modules. It systematically covers the setup process for several supported devices, including the RAK Wireless LoRa WisBlock Core RAK4631, T-Beam T22 V1.1, T-Lora T3 V1.6.1, HELTEC WiFi ESP32 LoRa 32 (V2 and V3), HELTEC E290, ESP32 / E22 modules, and the T-deck from Lilygo. The guide specifies support for the **EU433** frequency band, ensuring amateur radio compatibility, and details the use of an online flash tool for ESP32 modules and an embedded drive for RAK modules. It further describes accessing the MeshCom 4.0 Dashboard and Map functionalities, crucial for network visualization and management. Firmware configuration for ESP32 modules is meticulously outlined, covering essential parameters such as setting callsigns, country codes, and gateway parameters via a serial console like PuTTY. Commands for activating gateway mode, setting internet IP addresses, and configuring WLAN SSID and password for modules with WLAN capability are provided, enabling modules to function as either clients or gateways within the MeshCom network.

The Meshtastic documentation outlines critical LoRa configuration parameters for node operation, emphasizing regulatory compliance. It details settings such as Region, Modem Preset, Max Hops, Transmit Power, Bandwidth, Spread Factor, Coding Rate, and Frequency Offset. A comprehensive table provides region codes, frequency ranges (e.g., US **902.0 - 928.0 MHz**), duty cycles, and power limits (e.g., EU_433 **12 dBm**) for numerous countries, including the US, EU, China, and Japan, alongside a 2.4 GHz band option. It explicitly states that devices within a mesh must share identical _Region_ and _Modem Preset_ settings for full communication. Modem Presets, like _LONG_FAST_ (the default), optimize for either speed or range, directly impacting network congestion and message delivery delay. For instance, SHORT_TURBO offers the fastest speed and shortest range, while VERY_LONG_SLOW provides the longest range but is less reliable for mesh formation. The document also highlights specific duty cycle limitations, such as the 10% hourly limit for EU_433 and EU_868 regions, and provides command-line interface (CLI) examples for configuring these parameters.

Demonstrates firmware for microcontrollers like the _ESP32_ to implement a LoRa APRS iGate and Digipeater. This project leverages LoRa for packet radio communication, allowing amateur radio operators to bridge the gap between LoRa-enabled APRS stations and the global APRS-IS network via WiFi. It details the setup for both iGate and Digipeater modes, including features like transmitting APRS-IS packets over LoRa to local stations and a 30-second buffer in digipeater mode to prevent packet storms. This firmware offers an Ultra Eco Mode, achieving current consumption between **7mA** and **13mA**, making it suitable for remote, battery-powered deployments. The integrated WebUI simplifies configuration and management, providing an accessible interface for hams to deploy and maintain their LoRa APRS infrastructure. It supports sending weather telemetry packets and adheres to APRS protocols, released under the GPL-3.0 license.

Operating a _MeshCom_ node requires specific firmware, and this web-based installer, developed by OE1KFR, streamlines the process for ESP devices. It provides a user-friendly interface for flashing and updating the MeshCom firmware, emphasizing the critical step of using the ERASE option during initial installations or when transitioning from other applications. The tool also advises users to verify their device settings after upgrading to firmware version **4.35p**, ensuring proper operation and configuration retention. This installer simplifies the deployment of MeshCom for amateur radio operators interested in mesh networking and LoRa applications. By offering a direct web interface, it removes the need for complex local toolchain setups, making it accessible for a broader range of hams. The direct download option for firmware versions further enhances its utility, providing flexibility for users to select the appropriate release for their specific ESP hardware.