VHF Splitter - power from which switch?

[terah]

I've just bought a Vesper AIS and VHF splitter and trying to work out the best way to wire everything.

VHF sits on it's own switch on the fuse panel and had planned to add the AIS to the instruments switch.

Where should I power the splitter from? Or does it not matter as the splitter only needs to 'split' if both are on?

[colemj]

When powered off, that splitter stays on VHF. Power to the splitter is only needed for the AIS operation, so best to just wire it to the switch that powers the AIS.

Otherwise, it really doesn't matter where it gets its power, or that it is powered on when the AIS is not.

Mark

[Snore]

I just finished doing the same install.

After reading about a stolen boat recovered not far from me--- my AIS and splitter are wired direct to the house battery, with an in-line fuse.

If occasional privacy is an issue, use the brown wire on the Vesper to suspend transmitting.

If you don't want to do as suggested above, wire the splitter to BOTH the VHF and AIS circuits- then use diodes to isolate the two legs. This will ensure that the antenna is available to either device. But leaves the am/fm radio on its own.



Sent from my iPhone- please forgive autocorrect errors.

[ka4wja]

Terah,
I'm with Mark, colemj, on this....
Wire the Vesper SP-160 "12vdc power" to the same breaker as the Vesper AIS transponder...

The default of the SP-160, when it is powered off, etc. is to have the antenna always connected to the VHF-DSC-FM Voice radio (and the AM/FM stereo output, although I've found my small powered TV antenna at the masthead superior to my marine VHF antenna for FM radio reception anyway, so no need for that from the SP-160)


And, I'm not a proponent of leaving the AIS transponder running when docked / moored.....it just isn't necessary in most situations, and in crowded harbors this would cause serious clutter on so many AIS screens / chartplotters that most would find AIS a waste....
(yes, I understand that it is possible to track a stolen boat from its AIS transponder....but, if your boat is in a situation where it is likely to be stolen, there are better approaches...like not keeping the boat there...


Seriously, take Mark's answer and go with it...



Fair winds...

John

[wrwakefield]

Originally Posted by terah

I've just bought a Vesper AIS and VHF splitter and trying to work out the best way to wire everything.

VHF sits on it's own switch on the fuse panel and had planned to add the AIS to the instruments switch.

Where should I power the splitter from? Or does it not matter as the splitter only needs to 'split' if both are on?

We are in the process of finishing our install today, and, as discussed by Mark and others in this thread, are powering it with the AIS feed since VHF is not dependent upon the splitter being powered.

Regarding the mention about keeping AIS on for tracking in case someone borrows your boat without permission, we have two strategies:

First, we do leave AIS on when traveling on the boat and when anchoring [but not in the marina...] with the appropriate status being broadcast by AIS. [e.g., Underway, At Anchor, etc.]

Second, we cover remote vessel monitoring [including anchor watch, bilge pump running, shore power off, detection of movement onboard, boat traveling without permission, etc.] with a Siren Marine vessel monitoring device that sends text messages you control [and works anywhere there is cell coverage world wide...]

However, it is dependent upon cell coverage. But it won't be obvious to someone joy riding our boat [a very low probability where we currently cruise...] that this device is tattling on them, so we view it as a reasonable precaution- especially given the plethora of other features it brings to the table. [There is a brief article on our blog if you are interested in more details and why we installed a remote monitoring system.]

Thank you for choosing to transmit as well as receive AIS- improving safety for everyone.

Cheers!

[Jim Cate]

Hmmm...

If you wire the transponder to a different source than the splitter, would this not allow the situation of the AIS transmitting into an open circuit if the splitter power was off? At two watts, I dunno if any damage would accrue, but in general it is bad practice to not have a matched load on the output of the transmitter.

Jim

[colemj]

Originally Posted by Jim Cate

Hmmm...

If you wire the transponder to a different source than the splitter, would this not allow the situation of the AIS transmitting into an open circuit if the splitter power was off? At two watts, I dunno if any damage would accrue, but in general it is bad practice to not have a matched load on the output of the transmitter.

Jim

Yes, this is true. It probably wouldn't hurt the AIS, but it is bad practice, like you say.

In the OP's case, it sounds like his VHF would always be on, but he would want to be sure of that.

Mark

[terah]

Thanks all. Splitter and AIS now on their own switch. VHF is always on, AIS will be on as appropriate.

The Vesper is a nice bit of kit. Currently playing around with Memory Map on my phone taking nmea data from it.

Interesting comments about boat theft. There must be a way to set something up using an old mobile phone.

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