Propagation

Near-Real-Time F2-Layer Critical Frequency Map - This map can be used to determine the frequencies that will always be returned to the Earth. Transmitted frequencies higher than the indicated contours (which are given in MHz) may penetrate the ionosphere, resulting in lost power to space. The map shows the radio auroral zones as green bands near the northern and southern poles.

D-Region Absorption Prediction - This map represent the current position of the sun and how a solar flare influence an HF fade. Estimated recovery time is also represented. Includes son java and javascript animations of last two hour conditions

Hourly STD Solar and Geophysical Report - Boulder K-Indices, Planetary K-Indices, 10.7 cm solar radio flux updated every 30 minutes by Canada's Space Weather center

VHF/UHF Propagation - In the past few years there has been a growing movement from VHF frequencies (50-300 MHz) to UHF (300-900 MHz). Many, however, have found the move fraught with difficulties.

Amateur Chirp Project - Amateur projects to investigate radiowave propagation - G3PLX\'s chirp project, ionosonde database, and more

An introduction to HF Propagation - This article will help to unravel some of the mysteries as well as giving useful operating tips to maximize your chances of working that rare station by G4UCJ

Current solar images - Images from the Solar Dynamics Observatory and Atmospheric Imaging Assembly

D-Region Absorption Prediction - This map represent the current position of the sun and how a solar flare influence an HF fade. Estimated recovery time is also represented. Includes son java and javascript animations of last two hour conditions

Geomagnetic and Solar Indices - NOAA / Space Weather Prediction Center, Geomagnetic K-indices and Running A-indices, Local Noon Solar Radio Flux, Daily Solar Indices with SSN

Geophysical Alert Message wwv.txt - Broadcast via WWV and WWVH at 18 and 45 minutes past the hour. This message is updated every 3 hours. Reports current Solar-terrestrial indinces, Solar Flux, A-index, K-Index, forecast for space weather storms. Prepared by the US Dept. of Commerce, NOAA, Space Environment Center

High Frequency Active Auroral Research Program - A Scientific endeavor aimed at studying the properties and behavior of the ionosphere.

Hourly STD Solar and Geophysical Report - Boulder K-Indices, Planetary K-Indices, 10.7 cm solar radio flux updated every 30 minutes by Canada's Space Weather center

Near-Real-Time F2-Layer Critical Frequency Map - This map can be used to determine the frequencies that will always be returned to the Earth. Transmitted frequencies higher than the indicated contours (which are given in MHz) may penetrate the ionosphere, resulting in lost power to space. The map shows the radio auroral zones as green bands near the northern and southern poles.

NOAA Space Weather Scales - The NOAA Space Weather Scales were introduced as a way to communicate to the general public the current and future space weather conditions and their possible effects on people and systems. The scales describe the environmental disturbances for three event types: geomagnetic storms, solar radiation storms, and radio blackouts.

Propagation Planning for DXpeditions - 6 Steps for a More Successful Trip by Carl Luetzelschwab K9LA

Radio Wave Propagation - A PDF document, used for ham radio training, that cover all aspects of radio wave propagation

Report of Solar and Geophysical Activity - The Report and Forecast of Solar and Geophysical Activity is the primary daily report prepared by SEC. It provides a summary and analysis of solar and geomagnetic activity during the previous 24 hours as well as the most recent solar indices. It also provides a forecast of activity and indices for the next 3 days.

RF Skywave Propagation - Excellent presentation on RF skywave propagation by Greg, N6LYU

SEC's Radio User's Page - Provide radio operators with current data on the state of the ionosphere. Real-time Displays, Recent Space Environment Reports, Ionospheric Data Sets, Summaries & Medium Range Forecasts

The Ground Wave - About ground wave, article by moonraker.com.aut

Today's Space Weather - SEC - Another interesting reports page with plots and graphs of solar flux. Interesting resources provided here includes, Solar images, a text 3 day solar geophysical forecast, a 3-days Solar X-Ray flux plot updated evety 5 minutes, The Satellite Environment Plot, combines satellite and ground-based data

VHF Propagation Maps - Experimental maps that show real-time VHF propagation derived from analyzing data gathered from the APRS-IS network.

VHF/UHF Propagation - In the past few years there has been a growing movement from VHF frequencies (50-300 MHz) to UHF (300-900 MHz). Many, however, have found the move fraught with difficulties.

WSPRnet Weak Signal Propagation Reporter Network - A group of amateur radio operators using K1JT's MEPT_JT digital mode to probe radio frequency propagation conditions using very low power transmissions. Computer sent/received Morse signals received by amateurs and collected on an online database.