This is an HF propagation planning tool, similar to the Radcom Predictions] found on Proppy (which are in turn based on the charts found in the back of RSGB's RadCom magazine). While other tools, like VOACAP and Proppy, are based on sunspot-number curves and tables of "monthly average" ionospheric conditions, this planner uses a 24-hour prediction based on the prop.kc2g.com realtime model. In other words, they're the Farmer's Almanac, and we're the weather forecast.

Enter your location and click the button, and you will see charts presented for a variety of locations around the globe. Each chart has a column for each hour of the day, and a row for each amateur band. The cell at that row and column indicates the predicted probability of communication being possible on the selected mode (BCR, indicated by color from blue to red), and the predicted signal strength, in S-units. The number will be bold if it exceeds the predicted manmade noise strength (in the 25th column).

By default the times shown are in UTC, with midnight UTC on the left. You can also choose to have the headings in local time for your time zone, and to have the table start at midnight local time, or at the current hour.

You can adjust the antennas on each side of the path. You can choose an antenna type, and for horizontal antennas you can also choose a height above ground. A height in feet or meters will be the same height above ground for all bands, whereas a height in wavelengths represents a different antenna for each band. If you select the "Isotropic" antenna you can input a gain value, which will be used for every direction and elevation. An isotropic antenna with positive gain is completely impossible, but it comes in handy for simulating an antenna that you can't find on the list.

With the "Custom Site" option you can add one more RX site which will show up at the start of the list.

As with all forecasts these aren't 100% reliable, and you shouldn't be surprised if you can't make a contact that it says you should, or if the band is open when it says it isn't. But I hope that you will find this a useful tool both for casual use and for planning contest weekends.