Home provides forecasts of enhanced VHF/UHF radio communications owing to changes in weather that reflect favorably on the radio refractive index. The forecast model, which has been available to a limited audience since 1997, is for use primarily by radio amateurs in the east and central USA. In striving for a systematic approach to propagation prediction, we derive forecasts solely from tabular data drawn from standard radiosonde measurements taken twice daily.


The basis of the forecast model is outlined in the article "Practical Tropospheric Model for VHF/UHF Propagation Prediction," which originally appeared in the National Weather Digest (National Weather Association), Vol 22, Number 2, for June 1998. We also include an addendum in response to user questions and comments received since the article's publishing, as well as to address a variety of basic and evolving VHF/UHF propagation issues.Go There

Propagation Map

The map provides a forecast approximately 12 hours in advance for overland paths that are likely to experience enhanced conditions. Forecasts become effective at 0Z and 12Z each day. Shaded regions indicate areas where stations can expect significant enhancement, i.e., tropospheric conditions that give rise to radio communications beyond a given station's usual working range.Go There


We encourage your comments. In particular, we welcome activity reports from the Rocky Mountain region and from shore-based areas in our continuing effort to extend and improve the model. Please direct all communications to Thank you for visiting.Go There