Chapter 5 - Determining Your Position957 Operator’s Manual, Rev. B Page 61TDs. The accuracy from this conversion is generally betterthan 500 to 1500 feet.This feature is called Phantom Loran, which helps you movefrom using loran to using GPS. Phantom Loran lets you displayyour position as TDs, or enter waypoints as TDs. You can usethe 957 to simulate the full operation of a loran receiver, usingall of the 957’s navigation functions as if it was actuallyreceiving loran signals.These calculated TDs won’t exactly match the positions ofpreviously recorded TDs obtained directly from actual loransignals. In most areas, TD errors shouldn’t exceed onemicrosecond. However, larger errors are possible in areas withpoor configuration, or for which the 957 doesn’t haveaccurate, factory-programmed ASF correction points.Selecting anddisplaying PhantomLoranTo display position coordinates as Phantom Loran TDs:1. Press the STAR key to display the OPTIONS/SERVICEINFO screen.2. Press the NAVIGATION OPTIONS menu key, then high-light the NAVIGATION SOURCE option.3. Press the EDIT menu key, then press the CURSOR PAD toselect PHANTOM LRN.4. Press the ENTER key, then press the RETURN menu key.5. Press the CHART key to display the GPS POSITION screen.6. Press the CHECK LORAN key to display the PHANTOMLORAN screen.
