Amateur Radio Station OH6BG

QTH: VaasaFinland
63 05 N, 21 35 E

This page is dedicated to high-frequency propagation and prediction. If you would like to comment or suggest a link, please address your email to

My Current Projects

> VOACAP Quick Guide. This is a brief, a work in progress, guide to using VOACAP (Point-to-Point High-Frequency Ionospheric Communications Analysis and Prediction Program). Also included is a selection of articles concentrating on some specific issues with VOACAP.

> Daily sunrise and sunset calculations for DXCC countries. Also Ionospheric Grayline calculations.

HF Prediction Software
HF radio waves propagate from a transmitter to a receiver via the ionosphere. There is only a handful of free high-quality prediction software available on the web. The NTIA/ITS package includes three prediction programs, VOACAP, ICEPAC and REC533.

> High Frequency Propagation Models (from NTIA/ITS). The home of VOACAP.

> HamCAP by Alex Shovkoplyas VE3NEA. This is a free HF propagation prediction tool for Amateur Radio, based on the VOACAP prediction engine. Integrates seamlessly with DX Atlas and IonoProbe.

> MultiProp - Using MultiNEC with VOACAP. See how your particular antenna, or any of several built-in antennas, will perform under varying ionospheric conditions. Results may be shown on area coverage maps, point-to-point 24 hour time plots, or point-to-point "distance along the route" plots. Multiple maps and plots may be created and then played back as an animation. Includes a simplified interface to the VOACAP program that gets you "into" propagation modeling with just a few mouse clicks.

> Signal-to-Noise Predictions Using VOACAP. A User's Guide, by George Lane. A definite must for all users of VOACAP.

See also: Personal Opinions about the Past, Present and Future of IONCAP (by G Lane), PropMan 2000 (a commercial program incorporating VOACAP features), ACE-HF, WinCAP Wizard 3

Antennas are a most essential part of an HF communication channel. If you wish to be able to understand better how antennas behave, take a look at the following links. The NEC-Win is quite unique in its capability of saving antenna patterns in a format that can be understood by VOACAP.

> Antennas (by L. B. Cebik, W4RNL)

> NEC-Win Antenna Software

> EZNEC Antenna Software (by W7EL)

Monthly Smoothed & Effective Sunspot Indices
The sunspot index, along with the antenna model, is one of the most important user-defined parameters in HF prediction programs. Therefore it is essential to have access to these indices, preferably daily.

There are different types of sunspot indices such as real-time, daily, monthly and monthly smoothed. For instance, VOACAP, intended for use in long-term HF predictions, assumes the monthly smoothed sunspot number, not, for instance, the real-time sunspot number. For forecasts for a specific day, you may need an effective, real-time sunspot number - and a program known to support such forecasts.

> Provisional Monthly and Monthly Smoothed Sunspot Numbers (from SIDC, Belgium)

> Sunspot Index Graphics (from SIDC, Belgium)

> Predicted Monthly Sunspot Numbers (from National Geophysical Data Center)

> IPS Observed and Predicted T Indices

See also: Current Ionospheric Conditions (IPS), Effective Sunspot-Number Indices (NWRA)

Solar & Ionospheric Info
Below are some interesting links to services that can help you in keeping in touch with current solar and ionospheric data such as A, K and aurora indices.

> HF Propagation (by NW7US)

> European Region Real Time Ionospheric Map (IPS)

> Digisonde Data at Tromsø, Norway (see: Time Series Plots)

> Near-Real-Time MUF Map

> Space Weather

Copyright © 2004 Jari Perkiömäki, OH6BG