Setup menus – Garmin GPSMAP 180 User Manual

Page 76

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Using NMEA & DGPS Interface Settings

If you are using an NMEA interface format, the NMEA format must be specified

in the NMEA format field that will automatically appear when an NMEA option is

selected. The appropriate baud rate will be set automatically.

To select an NMEA format:

1. Select a NMEA IN/OUT format from the options page.
2. Highlight the NMEA Format field and press

T

.

3. Select a NMEA sentence format and press

T

.

4. The baud rate will automatically be set to the appropriate

speed. If you have selected an NMEA IN/OUT setting, you
must use the same NMEA format for both the input and output
device.

Tuning DGPS Stations

If the I/O Format is set to accept RTCM input/NMEA Output for connecting a

differential-ready GPS beacon receiver, you will need to tune a frequency in the

tuning field and select a bit rate. The default frequency will be 304.0 kHz, with a

bit rate of 100 bps, or the last DGPS frequency/bit rate selected.

To tune a DGPS frequency:

1. Select the ‘RTCM In/NMEA Out’ format from the options page.
2. Highlight the beacon receiver frequency field and press

T

.

3. Enter the desired frequency and press

T

. If you are using an auto-

matically-tuned DGPS receiver, you may enter 000.0 for the frequency.

4.

Press

T

to select a bit rate. Five bit rates are available: 0 (used for

automatically-tuned DGPS receivers), 25, 50, 100 and 200 bps. Press

T

to confirm. The DGPS status, along with the signal-to-noise ratio

of the tuned station, will be displayed at the bottom of the page.

A. Select the desired format from the NMEA

field. The baud rate will automatically be set

to the appropriate speed.

B. After entering a DGPS frequency, set the bit

rate to the speed indicated on the USCG sta-

tion chart. DGPS coverage, frequencies, and

bit rates are available from the Coast Guard’s

automated FAX service (703-313-5920).

64

A

B

SECTION

9

SETUP MENUS

NMEA & DGPS Setup

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