Our next ZOOM Club meeting is Tuesday, June 9th. Happy hour starts around 6:30pm, the general meeting at 7:00 pm, and the program at 7:30pm.
VOACAP
Jari Perkiömäki OH6BG will be presenting live from Finland on VOACAP.
Jari Perkiömäki, OH6BG, is a Finnish amateur radio operator and shortwave listener of more than 45 years, and the principal developer of VOACAP Online (voacap.com), the web-based HF propagation prediction service used by amateurs in more than 100 countries. He built the service in the early 2000s, drawing on a long correspondence with his mentor George Lane – the engineer who shaped VOACAP at the Voice of America. When Jari managed to compile the VOACAP Fortran engine for Linux, the path to the web was open, and VOACAP Online was born. He has continued to develop and maintain it for more than twenty years.
This presentation is a guided tour of VOACAP Online for the operating amateur. We begin with the inputs that shape every prediction – transmitting mode, power, and antennas – because the colors and curves you see later only mean what the inputs let them mean. From there we move to the wide-angle view: the CAP Wheel and ITUR Wheel, two 24-hour clockfaces that turn circuit reliability into something you can read at a glance, one ring per band. Running the two engines side by side is one of the most useful habits an operator can build: when they agree, confidence rises; when they disagree, you have learned something about the path. We then drill into the Prop Charts, where each band is unpacked across the 24 UTC hours and the three parameters that drive every VOACAP prediction reveal themselves as colored lines: REL – circuit reliability (how often the path is usable for your mode), SDBW – signal strength (with day-to-day variability shown explicitly), and MUFday – whether the band is physically open often enough to matter. The core skill of the session is reading these three together – the REL/SDBW/MUFday triangle – to find the sweet spot where the band is open, the signal is solid, and conditions are consistent. Finally, Coverage Maps widen the lens from “can I work this station?” to “where in the world can my signal be heard?” By the end, you will have a workflow that takes you from a single 24-hour wheel to a global footprint.
Watch the Groups.IO email reflector for the ZOOM login details.
