Antenna Splitter for VHF/AIS

[Howler]

Hi, We have the following B&G equipment:

• V60 VHF radio
• NAIS500 AIS Transceiver
• NSPL500 antenna splitter

Question 1 - The dealer wired all of the above directly (with appropriate fuses) to the house battery bank. Is this right? Shouldn’t they be wired to the navigation instruments circuit on the DC panel? I can turn off the VHF but I don’t have a way to turn off the AIS system. Seems silly to drain power 24 hours a day, especially when not cruising.

Question 2 - If I turn off power to the antenna splitter, will the VHF radio still be able to transmit alone through the antenna?

Thanks!

[Off Trail]

It does sound like poor practice. I like to have only the minimal connections direct to battery. We have separate panel breakers for instruments, VHF, and AIS.

Nice to be able to turn off the nav system at anchor while leaving AIS/VHF on.

Can't answer your second question, our solution is that AIS is always on when not at dock, so we power the splitter via the AIS power.

[S/V Illusion]

It’s common accepted practice to wire a radio directly to the batteries for a number of valid reasons. Not the AIS or splitter. Some people don’t differentiate.

[Howler]

Thanks. I’ll definitely put the AIs transceiver on a circuit with its own breaker. I’m just hesitant to power the antenna splitter without Question 2 because I’d still want the VHF to work when the AIS is powered off.

[Howler]

Duh. I can test that by disconnecting power to splitter!

[S/V Illusion]

Originally Posted by Howler

Duh. I can test that by disconnecting power to splitter!

Don’t know what splitter you have but most revert to the primary path when power is lost.
I never liked splitters - too many ways for them to fail and you won’t know it until you absolutely need it to work.

[Statistical]

Wire the AIS and splitter together to a breaker and you can turn off AIS as needed. If wired up right the splitter will work with VHF only when it loses power.

Obviously test this to verify. If removing power from the splitter causes VHF to stop working but AIS keeps working it likely is just wired up in reverse.

[Howler]

Thanks for the great feedback.

Epilogue: I wired the AIS and antenna splitter to a separate switch in order to be able to shut them off. I tested the splitter and it doesn't inhibit the VHF from broadcasting / receiving when it's powered down. As Statistical suggested, it passively passes through the VHF signal when not powered. It seems to only need power to detect and multiplex signals when both devices are operating.

[SailingHarmonie]

Originally Posted by S/V Illusion

It’s common accepted practice to wire a radio directly to the batteries for a number of valid reasons. Not the AIS or splitter. Some people don’t differentiate.

Without a fuse or breaker? I don’t think so!

Anybody wiring equipment on a boat without overcurrent protection shouldn’t be wiring boats. Period. Ever.

[S/V Illusion]

Originally Posted by SailingHarmonie

Without a fuse or breaker? I don’t think so!

Anybody wiring equipment on a boat without overcurrent protection shouldn’t be wiring boats. Period. Ever.

Where did I say without fuses? I didn’t think it necessary to state the obvious.

[Howler]

Originally Posted by SailingHarmonie

Without a fuse or breaker? I don’t think so!

Anybody wiring equipment on a boat without overcurrent protection shouldn’t be wiring boats. Period. Ever.

Please reread the original post. The first question said, in parenthesis, “WITH appropriate fuses.” But thanks for the reminder anyway .