Figure 16: Correct An150 And 8410 Wiring - NorthStar 961 Install Manual

SECTION TWO - Installation
Page 26
RF grounding
The grounding system is an equal partner with the antenna in producing
quality differential signals for the 961/962 differential receiver. Lack of
proper grounding can adversely affect differential signal strength as well
as SNR readings, and is the most common source of differential antenna
installation problems. The same grounding techniques that have worked
well for loran systems will work equally well for differential antenna
systems. Essentially, the ground system provides a secure connection to a
large electrical mass; ideally, the earth itself. On a vessel, this means
establishing electrical contact with "seawater" ground. On a steel vessel, a
good connection to the hull or steel pilothouse is sufficient. Wood or
fiberglass vessels require a metal ground plate or a thru-hull fitting. If the
metal ground plate is impractical, the engine block or the negative (–)
battery terminal can sometimes be used, but only as a last choice due to
stray electrical noise that these locations may present.
The 8410 ACU has a separate black ground wire inside the coupler base
that should be connected to an electrically quiet ground location. This
wire is the AC signal ground connection from the antenna input circuit.
The purpose of bringing it out is to make available a separate signal
ground path. For grounding, use #16 AWG minimum, and if possible, use
a grounding "strap" that is designed for this purpose.

Figure 16: Correct AN150 and 8410 wiring

961/962 INSTALLATION MANUAL Revision A