User manual GARMIN LORAN TD POSITION HANDBOOK

[. . . ] GARMIN Corporation hereby grants permission to download a single copy of this manual onto a hard drive or other electronic storage medium to be viewed for personal use, provided that such electronic or printed copy of this manual contains the complete text of this copyright notice and provided further that any unauthorized commercial distribution of this manual is strictly prohibited. GARMIN Corporation reserves the right to change or improve its products and to make changes in the content without obligation to notify any person or organization of such changes. Visit the GARMIN website (www. garmin. com) for current updates and supplemental information concerning the use and operation of this and other GARMIN products. GARMIN is registered trademark of GARMIN Corporation and may not be used without the express permission of GARMIN Corporation. [. . . ] An example would be chain 9610's Master Station and chain 8970's Zulu Station. These operate from the same transmitter located in Boise City, OK. 9960 (W ) 9960 (X) 9960 (Y) 2 Each Master Station transmits a pulsed radio frequency (RF) signal at a set time interval. This time interval is referred to as the Group Repetition Interval or GRI. It is not important to understand how this number is determined, just that it represents the Master Station and chain. After a Master Station transmits it's pulsed RF signal, each Secondary station after recieving the master station signal, transmits a pulsed RF signal at a set time delay. As the signals are processed by the Loran C receiver, the master signal is separated and used to measure the difference in time with each secondary signal. The time interval is very short, measured in millionths of a second or micro seconds. To determine a location, a Loran C must receive signals from a Master and two Secondary Stations of the same chain. From those three signals, a set of two TD's are constructed and using the TD's a location can be plotted. Loran TD Position Format Loran C Chart 3 Loran TD Position Format Position Format Field Loran C users can now use their TD's in GARMIN GPS systems. The new Loran TD position format provides users with the ability to create waypoints using TD's. When a waypoint is created using the Loran TD position format, a background conversion is performed on the TD's. Don't worry, this conversion process will maintain the integrity of the TD location and has proven to be accurate to within 30 meters most of the time. The new waypoint can be used for immediate navigation and/or stored for future use. Let's take a look at how to select and setup the Loran TD Position Format. Refer to your GPS Owner's Manual for directions on locating the Navigation Setup Menu. Selecting the Loran TD Position Format: 1. Using the Arrows or Rocker Keypad highlight Loran TD and press ENTER. Rocker Keypad After the Loran TD format is selected, a new field will appear to the right of the Position Format. The Loran Setup page contains fields where the GRI-Chain Number and Secondary Stations are set. To activate the Loran Setup page, highlight the Setup TD field and press ENTER. 4 The GRI-Chain Number and Secondary Station Identifiers that are set in the Loran Setup page will be used as a reference for the TD's when creating waypoints using the Loran TD Position Format. Note: If you do not have the correct GRI-Chain or Secondary stations set the waypoint will not be accurate. Loran TD Position Format Loran Chain Number Field The first setting is the Loran Chain Number. Accessing the field activates a dropdown menu containing the 28 available GRI-Chain numbers. Setting the GRI-Chain Number: 1. 2 Using the Arrows or Rocker Keypad, highlight the desired chain number and press ENTER. The next settings are Secondary Stations 1 and 2. [. . . ] The GPS uses the same process that it used to create a waypoint, in reverse. The GPS takes that GPS friendly position format and converts it to a TD for display. 6 Remember, it is a good practice to update any waypoint created using TD's while you are actually at the waypoint location. Consult your GPS Owner's Manual for directions on updating a waypoint. Loran TD Position Format For more information, visit the U. S. Coast Guard web site at: www. navcen. uscg. mil 7 Loran TD Position Format Notes 8 © 1999 GARMIN Corporation GARMIN International, Inc. [. . . ]