Humminbird 981 manual Follow these steps to stem mount the GPS receiver, To the cable as shown

98x_Manual_531376-1_A.qxd 2/23/2005 11:39 AM Page 24

GPS RECEIVER INSTALLATION (987c SI Combo models only)

NOTE: You will only need to perform this procedure if you have a GPS Receiver.

To optimize performance of the GPS receiver, mount it in an area that has full exposure to the sky. The effective area of reception is 10° above the horizon. Different circumstances determine the mounting method appropriate for your GPS receiver.

If you have…	Then use:
An existing antenna stem with	Stem Mount with Existing 1” - 14 Thread Stem
standard 1" – 14 thread
Access for cable routing under	Access Under Mounting Location
the mounting location
No access under the mounting	No Access Under Mounting Location
location

STEM MOUNTING WITH AN EXISTING 1" - 14 THREAD STEM

Follow these steps to stem mount the GPS receiver:

NOTE: If you have an existing stem for mounting the GPS receiver, proceed directly to step 2 of the following procedure.

1.Determine the best location to mount your GPS receiver. Preplan and test the cable routing to your control head before any drilling or cutting of your boat surfaces. If you have purchased hardware to stem mount your GPS receiver, follow the instructions included with that hardware to mount the stem (antenna pole).

NOTE: AS-EC10 10' extension cables are available from Humminbird® if your planned routing exceeds 20', (6 m). Maximum cable length, including extensions, should not exceed 50' (15 m).

NOTE: Remember to caulk or seal screw holes and drilled holes as needed to protect your boat from water damage.

	1	2. Screw on the receiver base to the stem first,
		making sure that the stem pipe does not
	2	protrude from the receiver base. This adds
		protection to the cable when pulling it through
		the pipe stem. In addition to this, de-burr the
		pipe edges to reduce cable abrasion.
		3. Use electrical tape to secure the NMEA pigtail
		to the cable as shown.
1	Receiver	3
		NOTE: Leave the NMEA pigtail secured to the cable
2	Receiver Base
		unless needed. This will make removing the receiver
3	Stem Pipe
		easier.

4.Route the GPS receiver cable through the stem and continue with the planned route you chose in step 1.

5.Attach the GPS receiver to its base using the included #6 - 7/8" (22 mm) screws.

		3
1
	2
	4
1 NMEA Pigtail Taped	3	Mounting Screws
2 NMEA Pigtail Cable Out	4	Cable Route

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