I'm excited to announce the public release of TERA — Terrain Evaluation for Radio Applications — now available at no charge to registered users right here on K6TU.NET.
TERA is a third-generation 2D ray-tracing tool for HF antenna terrain analysis, following in the footsteps of two pieces of software that shaped how many of us think about our stations: Brian Beezley (K6STI)'s TA and Dean Straw (N6BV)'s HFTA. Those programs introduced the ham community to the power of 2D ray-tracing for understanding how the terrain around your antennas shapes your signal. TERA is written entirely from scratch to carry that idea forward.
What's new
- Full UTD diffraction modeling. TERA implements a complete diffraction model based on the Uniform Theory of Diffraction, correcting known limitations in HFTA's earlier implementation. In some terrain scenarios you'll see results that differ from HFTA — and those differences represent improvements in accuracy.
- Horizontal and vertical polarization. TERA models both, broadening its usefulness across the full range of HF antenna designs hams actually put up.
- A modern implementation. Free of the computational constraints of early-2000s software, TERA leverages current hardware and is backed by an extensive test library validated against reflection and diffraction cases from TA, HFTA, and independent references.
- Seamless integration with the K6TU.NET Terrain Profile service. TERA builds on the same terrain generation service that has supported HFTA users here since 2015 — so if you've used the platform before, you already know the way in.
Made possible by the NCDXF
The interactive deployment of TERA was made possible by a generous grant from the Northern California DX Foundation (NCDXF), which funded a significant upgrade to the K6TU.NET compute infrastructure. That upgrade is what delivers the on-demand performance TERA's terrain analysis needs for real-time, interactive use. The NCDXF's commitment to advancing the technical resources of the DX and contesting community is deeply appreciated — this release simply would not have happened without it.
Standing on the shoulders of giants
TERA's development has been a privilege shaped by extraordinary expertise and generosity. Dr. James Breakall, WA3FET — whose foundational work in the early 1990s gave rise to both TA and HFTA — served as technical advisor throughout, holding the project to rigorous standards of physical correctness and contributing critical validation using Altair's FEKO professional RF simulation tool. His involvement has been indispensable.
My thanks also to Ward Silver, N0AX, for his perspective on serving the community well, and to Randy Thompson (K5ZD), George Fremin III (K5TR), Chris Hurlbut (KL9A), and others who tested early releases and gave invaluable feedback.
How to get started
TERA is free to registered users of K6TU.NET. Registration is free and quick — the sign-up exists only to keep the platform free of spam and abuse. Once you're registered, TERA is available directly through the K6TU.NET Terrain Profile service.
73,
Stu, K6TU