Wiring VHF

[actions]

I have searched the site and found a couple of bits but still need a bit of help is possible.

My rib currently has a fish finder and GPS. Both are directly wired to the battery. Positive with in line fuses to the isolater switch which is wired to the positive terminal and negative to the neg terminal on the battery.

I've just ordered a fixed VHF which should arrive soon, so can i just wire this in the same.
As in, positive to isolater and negative to negative battery terminal or do i need to it another way?

Want to get it right hence asking

Also Garmin who have been very helpful have sent this wiring diagram to me so i can wire the GPS 60 to the VHF and to the fish finder. Does it look right to you guys. Just thought the input and outputs might be wrong as surely there should be one of each on the nmea boxes or am i being a little thick. Maybe i shouldnt ask that........

[Erin]

Your wiring method sounds fine to me. Just make sure you put a fuse in and that the cable to the main switch from the battery is of sufficient size for the maximum power draw you will have. As for NMEA, the garmin can provide NMEA data to upto 3 devices from one of it's output ports. There will only be data passing from the Garmin to the devices so you only need to connect 'data-out' and ground on the Garmin onto 'data-in' and ground on the f/f and vhf.

[actions]

Thanks Erin,

When you say ground, what do i ground it to, negative battery terminal i assume?

Am i better to sort out some sort of busbar that i have seen mentioned elsewhere, or are three in line fuses ok. I dont plan on addding anything else to the boat.

[Poly]

Are you likely to be adding any more electrics in the forseable future? e.g. bilge pump, nav lights, etc? The approach you have is fine for one or two components but its starts to get a bit of a spagetti mess (fuses all in slightly different places so hard to find when an issue) when you have lots of stuff. The preferred option would be to bring the connections to a couple of "bus bars" - basically a big connector block with one (large) common wire back to the battery and/or isolator - some of the better switch "panels" basically have a bus bar and fuses built in.

Do you need an NMEA link between fishfinder and gps? I'm not sure what data the fishfinder is going to use? With more sophisticated gps/radio combos there may be a need for data flowing the other way - e.g. so a DSC distress message (or friend position polling request) received on the radio is plotted on the gps but I don't think you'll have that luxury.

[actions]

Hi Polwart.

For the time being i'm not planning on adding anything else to the set up. I will simply have the GPS, VHF and Fish Finder. The only reason i thought i'd connect the GPS to the fishfinder was that the GPS has a display for depth but having read the manual i think i can change that so it can display other information therefore negating the need to connect the fish finder.

Your right on the plotting front too. I dont have that luxury.

Ok, so i could have two bus bars if i feel its getting a little untidy then, one for positive connections and one for negative ones and just one fuse to cover all three items? Am i on the right lines.

[Poly]

Originally Posted by actions

Ok, so i could have two bus bars if i feel its getting a little untidy then, one for positive connections and one for negative ones and just one fuse to cover all three items? Am i on the right lines.

You could probably get away with one master fuse for the whole lot, but I'd be inclined to individually fuse items if being as organised as this (I have not fused everything myself!) but especially for anything than won't have an on/off switch - if it develops a fault a fuse gives you an easy way to "kill" an device.

[actions]

Thanks very much,

Once it arrives i shall have a look at how all the wiring is holding up and if its getting too untidy then i shall go down the bus bar route.

[rigi36]

If you do go down the bus bar route can I recommend Aquafax?

Home

The service I have received has been fantastic.

[Erin]

When I say ground I mean boat/battery negative. I would keep everything separately fused. A bus bar would make it neater but is not essential.

[actions]

Thanks All

Will let you know how i get on.

[Cookee]

The diagram from Garmin is correct. FYI the reason for two way communication between the GPS and the VHF is that on some combinations if you receive a DSC call it will come up on the GPS, likewise your own VHF will need to know where it is to send out a distress call. Don't forget to register for a MMSI number for the radio. Sorry to disagree with you Erin.

[Erin]

I may be wrong, but I didn't think his GPS could handle data input from the radio to display DSC calls and positions. If it does, then I'd certainly wire both tx and rx connections so that it sends data both ways.

[GaryC]

My understanding is that on a standard DSC call the lat/Long is not supplied so would really make this a waste of time (NMEA radio output to GPS)

Only on very specialist DSC distress set ups, so it would be someone like Coastguard that would use that functionality?

Gary

[Erin]

I have an Icom 505 which will transmit position data to my gps when it receives a position request/poll or a dsc distress to 'all ships'. It is really quite a clever system, though the only time I've ever seen it happen is when I was testing it alongside another boat. There are just too many butons to press when you're bouncing about on the waves to make it a practical day to day feature to use.

[Cookee]

Originally Posted by GaryC

My understanding is that on a standard DSC call the lat/Long is not supplied so would really make this a waste of time (NMEA radio output to GPS)

Only on very specialist DSC distress set ups, so it would be someone like Coastguard that would use that functionality?

Gary

Gary, Please be assured that I do know what I am talking about - if you have a look at your DSC radio you will see that there is a flap under which is a distress button (this is all covered in the DSC radio operators course) and pressing this button will send a digital distress call to the coastguard and any other ships within range - this signal will include your position which it gets from the GPS - this is the case for every correctly fitted radio - in fact some radios actually come up with an alarm if no position data is received.

NOT a waste of time!

[willk]

Originally Posted by Cookee

Gary, Please be assured that I do know what I am talking about - if you have a look at your DSC radio you will see that there is a flap under which is a distress button (this is all covered in the DSC radio operators course) and pressing this button will send a digital distress call to the coastguard and any other ships within range - this signal will include your position which it gets from the GPS - this is the case for every correctly fitted radio - in fact some radios actually come up with an alarm if no position data is received.

NOT a waste of time!

DSC 101, but not what the dude was talking about

[Cookee]

Originally Posted by willk

DSC 101, but not what the dude was talking about

Well I'll disagree with you as well! My point is that the benefit of DSC is that all suitably equipped vessels receive a DSC distress call and can either look up the position on their GPS or just look at the screen to see if they are near enough to help - Or am I missing the point and talking a load of rubbish?

If I'm sinking or on fire or similar I would hope there may be a friendly soul who would lend a hand like we did on Sunday afternoon?

[willk]

Originally Posted by Cookee

Or am I missing the point

It looks that way to me

Maybe quit swinging at me and read the guy's post again...

[Poly]

Originally Posted by Cookee

Or am I missing the point and talking a load of rubbish?

Originally Posted by GaryC

My understanding is that on a standard DSC call the lat/Long is not supplied so would really make this a waste of time (NMEA radio output to GPS)

John, I think what Gary is saying is he doesn't see any point in connecting NMEA out from the radio in to the plotter, because a normal DSC message does not contain and position information.

Gary has presumably never received a distress message and had to try and plot the position manually in a choppy sea to see if it was close enough to offer help - otherwise he would see the value in having it immediately appear on the plotter screen (either that or he is some sort of "Rainman" who mentally plots lat/long).

Whilst the value in responding to another's distress is good at the time, it is for most people likely to be a rarely used feature. However there is a potentially useful feature of DSC radios which is rarely used and I suspect GaryC is missing, called DSC Polling. This allows you to request from a friend their current position, which is returned digitally. With the correct plotter connected this will show up on the screen so you can "go to" them. If you regularly sail in company or meet up with friends this can be a useful feature.
Indeed you can use this with a group MMSI - so if ribnetters programmed the ribnet group mmsi into their radios it would be possible for someone with the right plotter to immediately see where all ribnetters in their radio range were (assuming they say "yes" to the polling request).

[Cookee]

Originally Posted by Polwart

John, I think what Gary is saying is he doesn't see any point in connecting NMEA out from the radio in to the plotter, because a normal DSC message does not contain and position information.

Gary has presumably never received a distress message and had to try and plot the position manually in a choppy sea to see if it was close enough to offer help - otherwise he would see the value in having it immediately appear on the plotter screen (either that or he is some sort of "Rainman" who mentally plots lat/long).

Whilst the value in responding to another's distress is good at the time, it is for most people likely to be a rarely used feature. However there is a potentially useful feature of DSC radios which is rarely used and I suspect GaryC is missing, called DSC Polling. This allows you to request from a friend their current position, which is returned digitally. With the correct plotter connected this will show up on the screen so you can "go to" them. If you regularly sail in company or meet up with friends this can be a useful feature.
Indeed you can use this with a group MMSI - so if ribnetters programmed the ribnet group mmsi into their radios it would be possible for someone with the right plotter to immediately see where all ribnetters in their radio range were (assuming they say "yes" to the polling request).