Gathering Components for adding GPS to Older VHF

[MalibuMike]

First off hello! I'm normally over in the Volvo Penta I/O forum. I have a 25 foot Parker pilot house and I'm trying to make sure all my safety equipment is in order since my kids will be on board.
First , I have very little understanding of electronics but can quickly understand concepts and clear instructions.
Here is what I have and what I'm trying to accomplish. I have a ICOM M502 VHF and it has a DSC button and the ability to have a GPS connected in the back. See image from manual. I also have a GPS on the roof of the pilot house and the cable comes down thru to a chart plotter.
I started by calling ICOM and they were awesome but the things they were telling me were a bit over my head. He said to get a red RCA connector and to solder some wires from the GPS unit and connect to the negative bus or something. I tried to follow but got lost and I dont even know what to order yet.
I did find this article with my exact radio and they do show parts but I dont know every where to buy the "interface box." Another pic attached from the linked article.
I'm wanting to know if the GPS cable I have can be "split" and connected to the back of the VHF. If not, can anyone direct me to a site where I can buy the components to make this work? The puck shown is easy but I don't know what these other two parts are or how to connect them all. I did find the12v-5v converter here.

 

[dingbat]

First off hello! I'm normally over in the Volvo Penta I/O forum. I have a 25 foot Parker pilot house and I'm trying to make sure all my safety equipment is in order since my kids will be on board.
First , I have very little understanding of electronics but can quickly understand concepts and clear instructions.
Here is what I have and what I'm trying to accomplish. I have a ICOM M502 VHF and it has a DSC button and the ability to have a GPS connected in the back. See image from manual. I also have a GPS on the roof of the pilot house and the cable comes down thru to a chart plotter.
I started by calling ICOM and they were awesome but the things they were telling me were a bit over my head. He said to get a red RCA connector and to solder some wires from the GPS unit and connect to the negative bus or something. I tried to follow but got lost and I dont even know what to order yet.
I did find this article with my exact radio and they do show parts but I dont know every where to buy the "interface box." Another pic attached from the linked article.
I'm wanting to know if the GPS cable I have can be "split" and connected to the back of the VHF. If not, can anyone direct me to a site where I can buy the components to make this work? The puck shown is easy but I don't know what these other two parts are or how to connect them all. I did find the12v-5v converter here.

What GPS do you have?

Scratching my head about the interface box. I see no reason for it. All your doing is adding a RCA connector to the TX and RX connections (bare wire) on the chart plotter.

The wire(s) from the gps antenna go directly to the plotter as well.

 

[Lou C]

I’ve done this twice with the same Garmin GPS and 2 different Standard Horizon VHFs (the original that I bought 15 years ago quit transmitting this summer so I replaced it with a similar unit). It can be confusing because the tx and rx wires may not be color coded in a standardized way. You might want to contact the manufacturer of the GPS unit and ask them. Once you know the colors of the Tx Rx and ground wires on each unit it’s easy. These wires are really small too small to crimp so use a terminal block to make your connections. First time I soldered them second time I used the terminal block much easier.
Also....always do a radio check to make sure your unit really transmits. I did this in the spring and didn’t get any answers. I then checked it with my portable VHF I keep as a back up and found that my original VHF was not transmitting! So had to get a new VHF.
They also sell VHFs with built in GPS, where you can transmit a distress call with your location although there are some advantages to having it linked to your GPS.

 

[dingbat]

These wires are really small too small to crimp so use a terminal block to make your connections. First time I soldered them second time I used the terminal block much easier.

UR IDC connectors are the way to go 19-26 awg.
Easy to use and provide a water proof connection

 

[Lou C]

UR IDC connectors are the way to go 19-26 awg.
Easy to use and provide a water proof connection

thanks nice tip, will keep that in mind for next time.

 

[MalibuMike]

Thank you. Those connectors look good. Looks like my unit is worth about $70 used on Ebay. $140 for a new unit with built in GPS at West Marine.
$30 bucks for GPS unit $12 bucks for 12v-5v and a few bucks for connectors. Maybe best just to get the new unit?

 

[dingbat]

Thank you. Those connectors look good. Looks like my unit is worth about $70 used on Ebay. $140 for a new unit with built in GPS at West Marine.
$30 bucks for GPS unit $12 bucks for 12v-5v and a few bucks for connectors. Maybe best just to get the new unit?

The VHF is a good unit. Have one on my boat as well.

Don’t understand the need for a 12 to 5v adapter. Position is coming in from the plotter via the RCA connection

 

[MalibuMike]

I found this today. My Furuno 1870 seems to have the ability to connect to a VHF but the ik-nmea2k2 cable they reference is almost $160!.

 

[Lou C]

It sounds like that you'd need that converter if one component uses NMEA2000 and one uses NMEA183 which is the older system. What do the GPS and your radio use? The radio I bought this summer uses NMEA183 just like my GPS so it was an easy connection.
It appears that these can be connected just by using the RCA cable, is that not so?
I can't see why you'd need a NMEA2000 cable for this.

 

[dingbat]

Both are older, discontinued units. Neither unit is NMEA 2000 compliant.

No short cuts here. Need to use NMEA 0183 connections. Solder RCA connector to Tx and Rx (NMEA 0183) connections on plotter

Don’t remember if you need a male or female RCA but this is what you need

RCA Male Jack Audio/Video DIY Pigtail Cable Yellow/Black

Helpful any time you need to attach to an RCA female connector. Length: 12" (305mm) Warranty is valid for two weeks, starting upon date of receipt.

ameridroid.com

 

[MalibuMike]

Here is some more info if it helps at all to go a different route. I have the Furuno 1870 chart plotter. The device has an internal GPS. There is an option for an additional GPS to be plugged in.I think I can wrap my head around a puck gps unit going to the VHF. Just want to make sure there is not a more direct route out of the chart plotter or if I should just scrap the whole thing and get the $150 unit with built in GPS at WestMarine.

 

[dingbat]

Here is some more info if it helps at all to go a different route. I have the Furuno 1870 chart plotter. The device has an internal GPS. There is an option for an additional GPS to be plugged in.I think I can wrap my head around a puck gps unit going to the VHF. Just want to make sure there is not a more direct route out of the chart plotter or if I should just scrap the whole thing and get the $150 unit with built in GPS at WestMarine.

Can’t get anymore direct than using the existing NMEA connections.

If you can’t get your head around splicing the pigtail I posted above to the NMEA wires coming out of the back of the plotter, don't know what to tell you.

Your turning a mole hill into a mountain range....

 

[MalibuMike]

I'm getting some of this but forgive me because this is one area I really struggle to understand.
I was on the boat today and found a few things that might change the path I go. I did confirm that the chart plotter can work without a GPS. I also found that there is a GPS on the roof and the cable from it was going in to the chart plotter.
With this info, can I adapt the GPS cabe to the VHF? Pics attached. The patina'd shot #3 is from the GPS. Shot #4 is the only unused cable coming out of the back of the VF/

 

[Lou C]

I’d try contacting Furuno tech support and ask them how to do what you’re trying to do.

 

[dingbat]

I'm getting some of this but forgive me because this is one area I really struggle to understand.
I was on the boat today and found a few things that might change the path I go. I did confirm that the chart plotter can work without a GPS. I also found that there is a GPS on the roof and the cable from it was going in to the chart plotter.
With this info, can I adapt the GPS cabe to the VHF? Pics attached. The patina'd shot #3 is from the GPS. Shot #4 is the only unused cable coming out of the back of the VF/

Ok....here is the manual for plotter

https://www.furunousa.com/-/media/sites/furuno/document_library/documents/manuals/public_manuals/gp1670f_1870f_operators_manual_ver_f.pdf

Bottom line...the two units are not compatible from a communications standpoint.

The plotter doesn’t support NMEA 0183 and the VHF does not support CanBus communications. Time for new unit(s)

Going forward....Pretty much everything has gone plug and play using NMEA 2000 communications. The standardized communications protocol of NMEA 2000 allows you to mix and components and peripherals of different manufacturers.

The down side, you must purchase (~$80) and install additional network infrastructure (Back Bone) to support the networking of the components.

 

[MalibuMike]

Ok....here is the manual for plotter

https://www.furunousa.com/-/media/sites/furuno/document_library/documents/manuals/public_manuals/gp1670f_1870f_operators_manual_ver_f.pdf

Bottom line...the two units are not compatible from a communications standpoint.

The plotter doesn’t support NMEA 0183 and the VHF does not support CanBus communications. Time for new unit(s)

Going forward....Pretty much everything has gone plug and play using NMEA 2000 communications. The standardized communications protocol of NMEA 2000 allows you to mix and components and peripherals of different manufacturers.

The down side, you must purchase (~$80) and install additional network infrastructure (Back Bone) to support the networking of the components.

Thank you. You definitely went above and beyond and helping me understand this. Even though my equipment is old and outdated, I do not wanna spend the money right now for all new systems. It seems like the best solution right now is to just buy a VHF With the GPS already built-in.