Raymarine ALPHA, Installation Instructions Manual, Page: 45 / 72

An RF ground point is typically a circuit with a very low-impedance signal at
Radio Frequency, connected to the sea via an electrode immersed in the sea,
or bonded to the inner side of the hull in an area that is underwater.
On vessels without an RF ground system , the drain wires and dedicated
ground connections (if available) of all equipment should be connected
directly to the vessel’s negative battery terminal.
The dc power system should be either:
• Negative grounded (“bonded”), with the negative battery terminal
connected to the vessel's RF ground.
• Floating, with neither battery terminal connected to the vessel's ground.
The preferred minimum requirement for the path to ground (bonded or
non-bonded) is via a flat tinned copper braid, with a 30 A rating or greater.
If this is not possible, an equivalent stranded wire conductor may be used,
rated as follows:
• for runs of <1 m (3.3 ft), use 6 mm2 (10 AWG) or greater.
• for runs of >1 m (3.3 ft), use 8 mm2 (8 AWG) or greater.
In any grounding system, always keep the length of connecting braid or
wires as short as possible.
10.7 Multiple performance display connections
Multiple performance displays can be connected together (daisy-chained)
for the purpose of an expanded system, via a separately available 8-pin
right-angled daisy-chain accessory cable. A maximum of 4 performance
displays can be daisy-chained in a series and a maximum of 10 performance
displays can be connected per system.
Example: daisy-chain network connection scenario
Important:
When daisy-chaining instruments together, ensure that a suitably-rated
fuse is installed before applying power.
The fuse rating must be
appropriate for the total power consumption of all daisy-chained
instruments in your system
. For more information, refer to:
p.42 — Inline fuse and thermal breaker ratings
1. Alpha 9 performance display — receiving power directly from a 12 V or
24 V power source via a separately available power and RayNet cable.
2. Alpha 9 performance display — receiving power from the previous
instrument in series via a separately available daisy-chain cable.
3. Alpha 7 performance display — receiving power from the previous
instrument in series via a separately available daisy-chain cable.
4. 8-pin right-angled daisy chain cable, available separately.
5. 8-pin right-angled power to RayNet and bare end power wires cable,
available separately.
6. Protective cap — must be fitted when connector is not in use.
Power connections 45