Boating in Canada Archive

Loran-C

TERMINATION OF U.S. LORAN-C SIGNALS:
In accordance with the 2010 DHS Appropriations Act, the U.S. Coast Guard terminated the transmission of all U.S. LORAN-C signals on 08 Feb 2010. U.S. Navigation Center (Homeland Security)

On Jan. 7, 2010, the U.S. announced it will begin decommissioning of all Loran-C transmitters on February 8, 2010. The service will continue temporarily to comply with Canadian agreements, but the Canadian Coast Guard has decided (not official) it will decommission its Loran-C system by Oct. 1, 2010. Contact the Canadian Coast Guard - ph: 613-998-1405. [CCG Loran-C | Wikipedia.org]

Locan-C is an electronic navigation system used for marine and air. Loran-C has been essentially replaced by the GPS, a satellite nav system. GPS and DGPS navigation receivers are inexpensive and accurate for use in recreational boating. Many aids to navigation are being removed because of these new electronic navigational systems.

Loran-C History

Loran-C was going to be phased out by 2000, but the U.S. decided to extend its use with $100 million in improvements. The new system emits very strong signals and have high timing accuracy. Loran-C is more accurate and reliable than ever.

U.S. transmitters used by Canadian boaters include Caribou ME, Nantucket MA, Shoal Cove AK, George WA. Canadian transmitters include Cape Race NL, Comfort Cove NL, Fox Harbour NL, Port Hardy BC, and Williams Lake BC.

The new Loran-C system supports new combined Loran-C/GPS receivers that provide superior navigation accuracy (although much more expensive). The new combined system provides true-north heading data for a stationary boat (valuable for controlling an autopilot). New Loran receivers do not require selecting a specific "chain", but work with all available signals. The traditional 6-foot electrical field Loran antenna will be replaced with a magnetic field antenna about 2 inches high, which will be very immune to interference from static, such as from lightning.

Canada and the U.S. share several Loran transmitter chains to provide optimum coverage. Many countries also own and control their own Loran transmitters, separately from the U.S. government. In fact, as long as the U.S. controls GPS satellites and uses SA (selective availability) without warning, it may be prudent to use Loran-C instead.

Advantage: Highly repeatable. You can use it to return to the exact same location.

Disadvantage: Accuaracy is reduced by land masses between you and the transmitter site (does not affect GPS). Fortunately, the Canadian Hydrographic Services (CHS) Loran chart overlays are corrected for this land effect, making very accurate navigation possible even on the Great Lakes - using the actual TD output of the receiver instead of the lat/long readout (calculated assuming open-water signal paths). This produces 30 metre (100') accuracy in positioning.

Disadvantages:

  1. Highly susceptible to electrical interference from the engine, power lines and television screens. The new Loran system will be better.
  2. Requires a ground plane installed for the receiver to work well. A portable Loran can be quite useless if the antenna is in the wrong location to get a good signal or conditions are not ideal.

Thanks to Arild Jensen's information on Loran in Today's Boating magazine, Spring 97.

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