Great Circle Routes (GC)
A 'Great Circle' is a full circumference of the Earth. The path taken by radio signals between two points on the Earth is a segment of a great circle.
Auroral Activity Level
The Activity Level is an index of auroral activity, i.e. a number from 1 to 10, also known as the Hemispheric Power Index. The index is derived from a statistical study of the data collected by the NOAA POES satellites during passes over the Earth's polar regions. The activity level is monitored in near real-time at NOAA's Space Environment Center. For further information about the POES satellite and the Activity Level, go to the following URL: http://www.sec.noaa.gov/pmap.
Organization of Hambone Help
Some of the following paragraphs relate to menu options of the Hambone application, and others relate to controls visible on the GUI. By clicking on a link below, you may access information about the selected item.
Great Circle Points
Controls Visible on the GUI
One of the first things you will probably want to do is to save your own location in a special file. To do this, click the /File/Edit My Location menu option. You will enter a name and a set of lat/lon coordinates. This information may be edited at any time by selecting the menu option again. You may then select your location as the GC origin, using the menu option /Customize/GC Origin Selection/Use my location.
On startup of 'Hambone' the Map Center is the North Pole. The pole may be changed to the South Pole: click /Customize/Dominant Pole/South. There is also, however, the option of setting the starting point of a great circle (GC) route between two points as the center of the map. In this case, the 'dominant pole' is irrelevant, and this option is greyed out.
To select the starting point of a GC route as your map center, click /Customize/Map Center/GC Start in the menu bar. If this option is selected, the appearance of the projection will change, and the great circle route will appear as a straight line on the map. This is a characteristic of the map projection (Azimuthal Equidistant). When this is done, the Short and Long Paths, with their beam headings and distances are calculated and displayed on the right side of the GUI. Hambone is currently unable to plot the long path.
When 'Pole' is selected as Map Center, Hambone draws the plot with one of the poles in the center. The pole may be selected by clicking /Customize/Dominant Pole followed by 'North' or 'South'. When GC Start is selected as Map Center, the 'Dominant Pole' option is disabled.
The Auroral Oval, at one or both poles, for a specific activity level may be displayed. The oval is selected by clicking in the check box, and then clicking the NOAA Logo button in the lower right of the GUI to redraw the plot. The orientation of the Auroral Oval changes with time, so the Universal Time entered is highly relevant to the possible effect it might have on radio transmission.
Use this dropdown list to select the level of Auroral activity you wish to display. (The Activity Level is derived from a statistical study of the data collected by the NOAA POES satellites during passes over the Earth's polar regions. The activity level is monitored in near real-time at NOAA's Space Environment Center. For further information about the POES satellite and the Activity Level, go to the following URL:
There are three options under /Customize/Activity Level Settings:
DXCC refers to the current ARRL DXCC country list, provided by Bill Brelsford, K2DI, of Bend, Oregon, sorted on either the primary amateur prefix or the country name. The 'Cities' list is from an entirely different source, and contains no prefixes or other ham radio data.
- Update UT when polling SEC for Activity Level--Automatically updates the UT to correspond to the center time of the Activity Level obtained by polling the SEC web site.
- Periodic update--Allows you to set a time interval (10 to 360 minutes) at which Hambone will automatically poll SEC for the latest Activity Level. UT is also set to the center time of the Activity Level.
- Activity Level in last 24 hours--Enter a UT in the Universal Time text boxes. If the time entered is earlier that the time of the latest available Activity Level from SEC, the closest matching time for today will be used to display an Activity Level. If the time is later than the latest Activity Level available from SEC, the closest matching time for yesterday will be used. Both the Activity Level and the Universal Time checkboxes will be updated.
Once the endpoints have been selected, click the NOAA Logo button in the lower right of the GUI to draw the map. When the plot is drawn, the GC route will be shown with an 'X' at the starting point and a triangle at the ending point. To label the endpoints, click the 'Labels' checkbox.
You can review the DXCC Country data by clicking on this option under /Customize. The option is not available when 'Cities' is selected in GC Destination List.
You can add a location to the 'Cities' list. All you need is a name, and the geographic coordinates of the location. Click /Customize/Add Location in the menu to add the location to the list. Once added, it will remain in the list. The list of locations is maintained in a file called 'cities.dat'. The file may be hand edited in any text editor, however, care must be taken to follow the format of the file, which is comma-delimited.
The 'UT Hr' and 'UT Min' text boxes are used to set the time of the auroral oval displayed.
You may enter the UT by typing in the text boxes. The new time will not take effect until you click on the NOAA logo button. See also Activity Level Settings above.
There are two options, under /Customize in the menu, which you may select to be activated when you start Hambone. You may activate one or both of these options:
The first of these causes Hambone to load the 'HBSettings1.dat' file automatically when you start Hambone. You may, of course save any of your favorite settings as the default (overwriting HBSettings1.dat).
The second option causes Hambone to ftp to the Space Environment Center's web site to obtain the latest auroral activity level. In order for this to be successful, you must be already on line.
In the lower left corner of the application, there is an SE (Space Environment) Logo. This is a button that will, provided you are on line, poll the Space Environment Center's web site (http://sec.noaa.gov/ftpdir/lists/hpi/) to get the latest auroral activity level. The activity level changes fairly frequently, at least several times a day.
To zoom, you must select a 'rectangular' area of the displayed map. This is done by Shift/clicking the mouse at two opposite corners of the desired area. This can be tricky, because the 'rectangle' is interpreted as geographic coordinates, not pixels. Keep an eye on the lat/lon grid lines to help you locate the appropriate points to click.
Steps for zooming in on an area of the displayed map:
To return to the full, unzoomed, map, uncheck the 'Zoom' checkbox.
Once a Great Circle has been displayed, you may label the endpoints by
checking the 'Labels' checkbox.
The terminator is displayed by checking the terminator checkbox, and removed by unchecking it. The slightly darkened area is the nighttime area of the map, i.e. the area which is in darkness at 100 Km altitude. The area is determined by the current date and the time contained in the 'UT Hr' and 'UT Min' boxes.
In the lower right corner of Hambone is a NOAA Logo. Clicking this button will cause the map to be redrawn in cases where this doesn't happen automatically.
The locations tab shows the current selections in the origin and destination droplists. If Use my location has been selected, the first droplist will be disabled and unused. If DXCC locations are being used, the continents will also be displayed on the tab, below the droplists.
The coordinates tab displays the latitude and longitude of the locations showing in the droplists. If Use my location has been selected, the first set of coordinates is the user's coordinates.
You may save your configuration, i.e. your current selections, in a text file. You may save it in the default file, called 'HBSettings1.dat', by selecting /File/Save Settings/Save As Default from the menu. To save your settings with another filename of your choice, select /File/Save/Save As.... You may also edit these files directly, in any text editor. Keep in mind that Hambone uses a colon (:) to identify where the specified datum starts on each line. Make sure to preserve this syntax. (Use one and only one colon.) It would be wise to keep a copy of a good settings file under another name for safekeeping, in case the default 'HBSettings1.dat' file becomes corrupted.
To restore your saved settings, select /File/Load Settings File from the menu, then select either the Default File option to load the default settings file (HBSettings1.dat) or Select File to load another filename of your choice.
You may save any displayed image in PNG (Portable Network Graphics) format. You will be prompted to provide a filename. There is an option (Add Date Stamp) under /Customize which will put the current date and time in the lower left corner of the displayed image.
Naturally, clicking Exit will close the application.
- Click the 'Zoom' checkbox.
- Shift-click the left mouse button at one of the diagonals.
- Shift-click the left mouse button at the opposite diagonal.
- Click the NOAA Logo button to redraw.