Tutorial - Preparing a Coverage-Analysis Prediction Set

There are two types of prediction sets suitable for use with the Coverage-Analysis View – the grid fields and the grid squares types. Each has good and bad in its favor. The grid field prediction set only requires a few minutes to create but provides rather poor “resolution” and therefore a coverage display that appears somewhat crude. The grid squares prediction set provides good resolution and a nice coverage display but requires an hour or more to create. So for a quick look the grid fields prediction set is ideal and for closer study the grid squares prediction set is far more appealing. For information see the section “What Are Grid Fields and Squares”.

Setting up to create a Coverage-Analysis Prediction Set –

On the Master-Control Palette click the “Circuits” button to access the Circuit-Configuration Manager. We will briefly visit and configure each page of the Circuit-Configuration Manager. To make the following configuration selections you will use the “navigator buttons” – the group of buttons near the bottom of the window just above the status line.

It is worth noting that you do not have to use the pre-configured “input parameter groups” as we will do. You can change any item in the “input parameter groups” as you wish. However as you can create new “input parameter groups” it seems best to do so and not make random changes to existing input parameter groups.

1. The initial page is the “System” page and we must select the type of signal we will use as this allows WinCAP Wizard to figure out some otherwise confusing input needed by VOACAP. Click the “navigator – next system group” button – the third button in the group near the bottom of the window – click repeatedly until the “box” toward the window upper left under “Group Name” shows the “CW – Short Path” group.
2. Click the “Station” tab and insure the transmitter location you want to use for the prediction set is the currently selected station. If not again use the navigator control.
3. Look on the “Receive System” page and select the group named “Big-Gun Station”. See the section “About The Defaults”.
4. On the “Month” page insure the check box labeled “Use current month” is checked – unless you need predictions for a different month in which case un-check it and select your desired month using the “Predict Month” control. It is recommended to keep the “Daily Coefficients” - which switches to URSI coefficients - un-checked - use “CCIR” coefficients instead. Finally insure “Use stored Smoothed-Sunspot Number” is checked.
5. Skip the page labeled SSN as the Month page settings take care of selecting the predicted smoothed-sunspot number for the selected month.
6. On the "Xmtr Antennas" page select the group named “Coverage Antennas”. See the section “About The Defaults”.
7. Finally – look on the “Frequencies” page – if your coverage prediction set is for use in a contest select the group named “Contest Bands”. If your coverage prediction set is for general use you may want to select the group named “All Bands”.

What happens when you analyze? -

When you click the Analyze button – for either type of grid prediction set – WinCAP Wizard creates “input files” for VOACAP along with a control type file. There is one input file each hour “multiplied by” the number of frequencies ordered. In the case of the “Contest Bands” frequency set that is 120 input files – but this all happens quickly as you see VOACAP execute right away – the input files are small at under 1K each but total about 104K. In response VOACAP creates an “output file” for each of the input files. For a “grid squares” type prediction set the output files are considerably larger at about 5.31MB each - for this example that amounts to about 637MB. The point of this extra information is to illustrate the fact that we need plenty of hard drive space for use as work area. The good news is these files are written over each time you analyze a prediction set so we don’t continue using additional hard drive space. But WinCAP Wizard does store the prediction data in database tables and those tables do continue to grow until you empty or clear them.

Analyze the Coverage-Analysis Prediction Set -

On the Master-Control Palette click the “Analyze” button to access the menu and – depending on your choice of grid fields or grid squares – then the appropriate menu item “Grid Fields” or “Grid Squares”.

How long did it take? –

WinCAP Wizard keeps track of the time required for prediction types other than point-to point. After VOACAP finishes and WinCAP Wizard gathers the data and stores it away click the Master-Control Palette Menu button and move down to Options and click the “Display Work Time” item. The “Working Time” window shows three time figures – the “Calc” is time VOACAP used – the “Parse” is the time WinCAP Wizard used and the third value is the total time required for the entire process.

Continued in the Tutorial – Using the Coverage-Analysis View section