VHF/GPS Wiring?

Little Hawk

Little Hawk

Active Member
Howdy,

Finally bought and installed a new VHF on the boat (my first).

Question: I'm wrestling with whether or not I've wired the GPS into the radio (for distress signal connection) correctly.

I have a Lowrance LMS-350A and the best I can tell from the Lowrance/manual is that the Green & White wires on the power cord are for the NMEA interface. The White wire sends position date etc. I've taped both the Grn & Wht wires together from the Lowrance and connected them to both the Yellow & Green on the ICOM GPS Receiver lead. I did this because the instructions were a bit ambiguous to me and I tried to cover all the bases. Not sure how to test it or determine if it's hooked up right.

Anyone had experience with this stuff?
 
maybe contact coast guard, they might let you test the distress signal if they know its coming?

Definitely something you want to sort out BEFORE you need it.
 
I just did mine.

What model ICOM is it?

If your GPS position is showing on the VHF, you did the output on the GPS to the input on the radio correctly. If you do a position request and the other boat's position shows up on your GPS (assuming it is a talker and a listener-I just checked your manual and yours is), then all your wiring is done correctly.

I doubt the Coast Guard is going to approve of a test distress call since the signal not only goes to them, it goes to all boats within range with a DSC radio.

I assume you also have your Restricted Operator's Certificate (M) with DSC endorsement which is now also required.
 
quote:Originally posted by Little Hawk

Howdy,

Finally bought and installed a new VHF on the boat (my first).

Question: I'm wrestling with whether or not I've wired the GPS into the radio (for distress signal connection) correctly.

I have a Lowrance LMS-350A and the best I can tell from the Lowrance/manual is that the Green & White wires on the power cord are for the NMEA interface. The White wire sends position date etc. I've taped both the Grn & Wht wires together from the Lowrance and connected them to both the Yellow & Green on the ICOM GPS Receiver lead. I did this because the instructions were a bit ambiguous to me and I tried to cover all the bases. Not sure how to test it or determine if it's hooked up right.

Anyone had experience with this stuff?
Click to expand...

First of all, What model Icom VHF do you have?

I have an Icom 422, going by that and the manual for the LMS 350, here is what I get:

Icom 422 +++++++++ LMS 350a
Red - In +++++++++ White - Out
White - Out +++++++++ Green - In

Check your own wire color codes for your VHF

quote:The white wire is for a NMEA interface. The LMS-350A sends data to another electronic navigation devices through the white wire. It receives data from a differential (DGPS) beacon receiver through the green wire. If the white and green wires are not used, tape their ends so that they cannot short.

To connect a device to the LMS-350's NMEA output (white wire), attach
a shielded, twisted pair cable from the device's NMEA intput to the
white wire on the LMS-350's power cable. Solder the ground conductor
of the twisted pair and the shield to the black wire on the power cable.

Do not connect the shield to the other device. Use the green and black wires in the same manner to attach a DGPS recevier's output to the LMS-350's input (green wire). See the other instrument's manual and the NMEA section in this manual for more information.
Click to expand...

I take this to mean that you tie the shield to the shield of the Black Neg. Ground wire on the GPS.

The diagram in the manual does not show wire colors for the GPS/VHF connections - pretty poor really. :(

One thing I remember from doing mine, is that the wires are very small and the jackets will melt very easily while soldering. Be carefull!

You should be able to get a GPS position on your radio display when hooked up correctly.


Good luck!


Jim's Fishing Charters
www.JimsFishing.com
http://ca.youtube.com/user/Sushihunter250
 
You also have to make sure that the data rates that the Lowrance sends match what the ICOM wants to hear. Read the ICOM manual, it should tell you if it expects a 2400 baud or 9600 baud signal. On the Lowrance, there will be a NMEA output menu to change the signal to that data rate.

TenMile
<'((((><
 
It's usually 4800 baud, but the Lowrance manual does not make mention of this so that should be the default.

Page 80 of your Lowrance manual shows you how to setup NMEA 0183 for the GPS.

Taping the wire connectors is okay to make sure everything works, but you should be doing more to make the connections more permanent.

Some people use a Euro style terminal strip, and some twist the wires together, then use small butt connectors and then heat shrink the insulation. If you are comfortable soldering 28AWG wires, then good on ya.
 
Thanks a lot dudes!

Sorry I took a bit to respond. I do most all my internet/computer **** early in the A.M.

My new radio is an Icom IC-M304 and I have poured through the manual both for it and the Lowrance. Both manuals leave plenty to interpretation. I didn't solder the connections; just twisted them together then sealed with that black Bic-lighter heat-shrink crap.

When I get time, I'll hook up and turn on the Lowrance and do the input programing to get it in line with the radio. I just noticed in the Icom manual that the 'GPS' tag on the display will flash if the GPS data is invalid. Even a carpenter should be able to figure this one out...
 
On page 31 of your Icom radio explains the connections.

Unfortunately your radio is only a listener, not a talker so it won't be able to transmit data to your GPS when a distress signal is received or during a position request. If it were me, I would get a different radio just based on that.

Otherwise though, the white wire (Out) on the Lowrance gets connected to the yellow (In) wire on the ICom. The green wire on the Icom gets connected to ground. In your case, the green wire on the Lowrance would not be connected to anything (just snip and tape it).

After you configure NMEA 0183 on page 80 of your GPS manual, you then should see the position on your radio.

Good Luck.

P.S. This video will show you the benefits of having a radio that can also transmit information to the GPS. In other words, the radio needs a NMEA+ Out wire.

http://albums.phanfare.com/4892322/2160277_2325617#imageID=31027543
 
Howdy,

Cool video. That said, I don't really need the DSC position request feature because my (older) Lowrance doesn't have mapping.
All I care about is being able to hassle Wolf to find out where the fish are and have my position instantly relayed in a distress situation; this radio will do that just fine.
 
hope this helps:
DSC_0022.jpg


the wire coming from left is the NMEA from my MFD. the two connects on the right are the VHF and the fuel mgt gauge. i would strongly suggest you invest in a VHF which now has DSC capabilities. that is the functionality that is current. pressing a single distress button sends a signal on 71, which is now monitored internationally, and provides your GPS location along with vessel description.

you will know if your connects are correct when and if your VHF, assuming it has the correct capabilities, displays your current GPS location.
 
whoops, thanks tiki. i should have also mentioned that you have to get your MMSI # before all the boat description info is available. since the FCC didn't want to get along with the canadian counterpart, it might be best to check with your electronics dealer about how you go about getting your number above the 49th.
 
It's very easy to get your MMSI number in Canada. Industry Canada (Spectrum Management) is the government body responsible for this.

You just fill out Annex A here:

http://www.ic.gc.ca/eic/site/sd-sd.nsf/eng/00009.html

I converted to Word format and then emailed it to victoria.district@ic.gc.ca (or you own local office) and 2 hours later, I had my MMSI.

One other thing that is different between here and the U.S. is that we are legally required to have a Restricted Operator's Certificate (M) with DSC endorsement in order to transmit on a DSC radio.
 
Thanks again guys!

Got me my MMSI number (and a cold beer) and I'm headin' out to the boat to see what damage I can drum up. Hell, it's only 12-volts... how bad can it get?
 
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