*** Satellite Finder Help

This is [VersionBuildString]

For updates, visit http://www.arachnoid.com/satfinder

Satellite Finder is (c) Copyright 2014, P. Lutus. All rights reserved.

Satellite Finder is CareWare (no money, now or ever). If you are curious about CareWare, you may choose to drop by http://www.arachnoid.com/careware at your leisure. It's not a requirement, and Satellite Finder is essentially free.

At this point, you may wonder -- if SatFinder is free, why bother mentioning that it is copyrighted? The answer is to prevent people from selling my free program. Yes, it happens.

*** Quick Introduction

Satellite Finder is a Java program that locates the relative positions of geostationary satellites for provided positions on Earth.

Satellite Finder requires a Java 1.7.0 or newer runtime engine.

The inputs to Satellite Finder are:

1. A configuration file that lists the satellites of interest and their orbital positions, and
2. The surface position of interest.

The first requirement is met by a data file in the Satellite Finder user directory (located on this machine at [userDir]/.SatFinder/satlist.txt). A default version of this file is provided when the program is first run. The user may edit this file to suit personal requirements and to accommodate changes in the names and positions of satellites as time passes.

On multi-user systems, each user gets a separate copy of this data file. This assures that individual choices do not create global changes to Satellite Finder.

The second requirement, that of surface position, can be met by entering a US state and city, or a US ZIP code, or by directly entering a geographical position.

Once a position has been entered, Satellite Finder produces a list of satellites and their azimuth and elevation angles for the entered position. Both true and magnetic azimuth are computed, as well as elevation and skew angle, for each satellite in the list. The position coordinates may be used to point satellite dishes or conduct site surveys for dish placement.

In the satellite list, the heading "Name" can mean the name of a satellite or a particular satellite receiver dish model, depending on context. "Longitude" means satellite longitude on the geostationary arc, "Azimuth True" means the desired horizontal pointing angle, "Azimuth Magnetic" is the same information corrected for magnetic declination, "Elevation" means the desired vertical pointing angle, and "Skew:0" and "Skew:90" refer to dish skew angles using the two most common conventions. All angles are in degrees.

*** In Depth

When Satellite Finder is first run, the program creates a set of data files to speed up the computation of satellite positions based on US states, cities and ZIP codes. These data files are located on this machine at [userDir]/.SatFinder. This data file creation task only happens once, so subsequent program starts are much faster than the first.

After having run Satellite Finder once, to change the satellite list to suit your own preferences, simply edit the plain-text file located at [userDir]/.SatFinder/satlist.txt. Each record in this file consists of a satellite name, a comma, and a longitude position in decimal degrees. West longitudes are entered as negative numbers, East longitudes positive.

* NOTE: when upgrading to a new SatFinder version, be sure to delete the directory located at [userDir]/.SatFinder before running the new version. This assures that any satellite changes are made part of your custom user data.

In typical field work a magnetic azimuth bearing is required. Satellite Finder uses a lookup data table of magnetic declinations derived from a NOAA declination predictor program named “GEOMAG” (more on this below). Both true and magnetic azimuth values are computed and provided in the display for each satellite. The magnetic declination values stop being valid for latitudes greater than +-80 degrees.

*** Specifics of Data Entry

The easiest way to use Satellite Finder is to choose a state, then a city, using the provided lists. These selections will produce a list of satellite positions for the chosen city in the right-hand window.

Another method is to type in a ZIP code, then press "Enter," in the ZIP code entry pane. This also will create a list of satellite position data.

Finally, one can type in a geographical position (latitude and longitude) in decimal degrees and press "Enter." This is the required method for non-US locations.

Each of the described entry methods automatically produces a data list when your entry is complete. For the state/city selection method, making a state and city selection triggers the generation of the data list. For ZIP code and geographical coordinate entry, pressing "Enter" in the entry pane causes the data table to be generated.

The satellite data list can be copied onto the system clipboard for use elsewhere. Just click the "Copy to Clipboard" button.

*** Troubleshooting

To solve mose common problems with Satellite Finder, simply delete the directory located on your system at [userDir]/.SatFinder, then run Satellite Finder again. This causes Satellite Finder to perform a new data installation, which updates the ZIP code database and the satelite list. This step is particularly important when upgrading from versions 4.4 to 4.5 or newer, at which point the ZIP code database was completely restructured.

*** Satellite Dish Installation Issues

Most satellite dishes come with clear instructions (or such instructions can be downloaded from the Web). The easy steps are setting the azimuth (horizontal angle), usually with the help of a hand compass. The elevation (vertical angle) is also relatively simple because most dishes have a calibrated elevation scale.

For the increasingly popular satellite dishes able to receive more than one satellite, there is a third required adjustment -- skew. In SatFinder, the rightmost values in the satellite data table are "Skew:0" and "Skew:90".These two values are used to adjust the tilt of a satellite receiving dish, with both commonly used ways to express the skew angle.

A word of explanation. Whenever a dish is located at a terrestrial longitude different than the orbital longitude of the satellite it's pointed toward, there is a difference in rotation angle between the satellite's sense of the horizontal and that of the dish site, and this difference may need to be accounted for.

Skew is only important for dishes that are equipped to receive more than one satellite (or non-U.S. dishes that don't use circular polarization). If your dish only has one microwave sensor and uses circular polarization (i.e. all U.S. dishes), don't bother adjusting skew.

By contrast, many newer dishes are equipped to receive two or three satellites simultaneously. These dishes need the skew adjustment. Multi-satellite dishes typically have a separate scale and adjustment for skew, clearly marked.

Negative "Skew:0" skew values, or "Skew:90" values less than 90 degrees, mean the dish is to be tilted toward the east (or counterclockwise when viewed from behind in the Northern hemisphere) by the specified angle. Positive values, or values greater than 90 degrees, mean a tilt toward the west (or clockwise).

For skew adjustments to be effective, the mounting mast for a multi-satellite dish must be vertical. The symptom of a bad skew adjustment is the inability to receive all the satellites equally well.

*** Miscellaneous Notes

In recent SatFinder versions, a list of satellite dish pointing angles for DishNetwork and DirecTV dishes are provided to simplify dish alignment. If you have a typical multi-LNB satellite dish from one of these vendors, you should be able to find your dish model in these lists -- just use the pointing azimuth and elevation values for your model. For single-LNB dishes, use the listed values for the satellite you're interested in receiving.

The magnetic declination in Satellite Finder is computed using a table of values generated by "geomag", a magnetic declination program supplied by NOAA (http://www.ngdc.noaa.gov/seg/geomag). There are actually two data tables which provide reference years of 2005 and 2010, and the program provides an estimate of the declination based on both the entered location and the computer's current date and time. The value provided by Satellite Finder, and the value provided by NOAA, will always differ to some extent, but the program's accuracy is more than adequate for dish alignment.
