The ITU‑R Recommendation P.833‑2 provides guidance on estimating radio‑wave attenuation caused by vegetation for frequencies between 30 MHz and 60 GHz. Because foliage conditions vary widely and experimental data are limited, the recommendation offers separate models for different frequency bands and path geometries. For a terrestrial link with one end inside a woodland, the extra loss is expressed using two parameters: the specific attenuation rate γ (dB / m) that describes short‑range scattering loss, and a maximum attenuation Am that caps the total excess loss due to additional mechanisms such as surface‑wave propagation and forward scattering. The excess attenuation for a path length d inside the vegetation is given by Aev = Am 1 – exp(–d γ / Am) » . This formulation allows engineers to calculate the additional loss when a transmitter or receiver is located within dense vegetation.
Edward F. "Ed" Hare, Jr., W1RFI, a long-time ARRL Lab engineer, passed away on October 10, 2025, at the age of 75. He was a dedicated ham radio operator, RFI expert, and contributor to ARRL advocacy efforts.
"This document is aimed at the Arduino developers, radio experimenters, hobbyists and anyone interested in building a receiver based on the Si473X IC family from Silicon Labs. This project is about an Arduino library for the SI473X BROADCAST AM, SSB and FM/RDS RADIO RECEIVERS. Frequency ranges of AM and SSB modes are 150kHz to 30MHz, and FM mode is 64 to 108 MHz."
This repository is intended to share implementations using the Si4735/Si4732 chip with the library written by PU2CLR/Ricardo Caratti. It includes projects for TTGO T-Display Board and Lilygo T-Display S3 Board.
Nick Farrow has created MeshBoard, a text-based bulletin board system inspired by the BBSes of the 1970s and 1980s, running on a Raspberry Pi using the Meshtastic mesh network. The project allows for menu navigation and interactive games like Tic Tac Toe and an Escape Room, with no internet required. It leverages Python to create a modular and easily extensible platform, with plans to expand features such as file transfer over the Meshtastic network.
This is a pre-order for the Quansheng UV-K5 radio directly from the factory with modifications for H.F bands and updated firmware. The radio also includes an antenna inductor change and audio quality fix.
