VOACAP Quick Guide

HF Propagation Prediction and Ionospheric Communications Analysis
by Jari Perkiömäki, OH6BG

What is VOACAP?

VOACAP (Voice of America Coverage Analysis Program) is free professional high-frequency (HF) propagation prediction software from NTIA/ITS, originally developed for Voice of America (VOA).

This 'work-in-progress' guide should get you well started with the software. A more comprehensive discussion about the finer details of using the software can be found in George Lane's book Signal-to-Noise Predictions Using VOACAP. A User's Guide. The book is now available on CD-ROM.

There is now also "The Official VOACAP Blog" - well, it's not too official.

NOTE: Running automated scripts to access VOACAP services is strictly prohibited unless agreed upon in advance with the VOACAP site owners.

Follow me on Twitter for the latest news

If you wish to keep abreast of the latest developments on my site, follow me on Twitter.

Real Propagation Visualized with FT8 Data

Explore the 50,000+ real-life propagation charts from one ITU zone to another ITU zone over the months of 2017-2019!

VOACAP Online Prediction Services

Point-to-Point Predictions

11M Point-to-Point Predictions

  Coverage Area Maps

11M Coverage Area Maps

VOACAP Propagation Planner
Visual tool for HF contesters and DXers
  VOACAP DX charts
Predictions for upcoming DXpeditions

Other VOACAP Related Services

VOACAP Greyline

What's New?

1. Downloading VOACAP

2. VOACAP - Backgrounds & Running the Prediction


The calculation engine, VOACAPW

Graphs & Colours

3. VOACAP - Understanding the Prediction



Signal Power & Noise Power

Antennas & Radiation Angles


4. VOACAP - Case Studies

5. VOACAP-related Papers

6. NTIA/ITS HF software HELP Topics

7. HamCAP User's Guide

8. Articles of interest





9. Tools & downloadable files for use with VOACAP

Find coordinates and Maidenhead grid locators just by pointing and clicking



Coordinate files

Save the coordinate files (*.GEO) at C:\ITSHFBC\GEOCITY\

Antenna and configuration files

Special Thanks
I wish to thank Mr George Lane for his friendship, invaluable comments and guidance - and his patience in this project. A special thank-you to Greg Hand who still maintains the code.

Disclaimer: Any software or service on this website is provided "as is". Use at your own risk.

© 2003-2023 Jari Perkiömäki OH6BG. SSN source for all VOACAP Online services: WDC-SILSO, Royal Observatory of Belgium, Brussels. Last update: 14 Feb 2023.