The behavior of radio (electromagnetic) waves as they traverse through space is referred to as radio wave propagation or radio propagation. To comprehend radio communication, it is imperative to delve into the study of antennas and wave propagation.

     The effectiveness of radio wave communication relies on three key factors: the transmitter’s power, the distance between the transmitter and receiver, and the receiver’s sensitivity in amplifying weak signals. Interference signals can disrupt reception at any given time, while the presence of noise and transmission line losses can render a strong signal incomprehensible.

     To fully grasp the significance of these factors, it is crucial to delve into the nature of radio waves and the conditions that impact their successful propagation.

The solar-terrestrial and HF and VHF propagation data are furnished and by Paul L. Herrman © Copyrighted.  

Propagation Tools & Widgets


The Voice of America Coverage Analysis Program (VOACAP) was created to forecast the transmission paths and frequencies for VOA broadcasts. VOACAP is an enhanced and rectified iteration of IONCAP, encompassing the entire theoretical framework proposed by John Lloyd, George Haydon, Donald Lucas, and Larry Teters during the period of 1975-1985. It incorporates modifications that were recommended and authorized by George Lane, Donald Lucas, George Haydon, and A. D. Spaulding (a globally recognized expert in HF radio noise predictions).


Proppy: HF Propagation Prediction. The tools provided by this web application allow users to predict available frequencies, signal levels, and corresponding reliability for high-frequency (HF) circuits. All forecasts are conducted utilizing the ITU’s ITURHFPROP software; a software technique for projecting the efficiency of HF circuits in compliance with Recommendation ITU-R P.533-14.

Solar X-ray Flux

Hourly Area Predictions – Image obtained from the Australian Government’s Office of Space Weather Service SWS – HF Systems (