Here's another one for our techies

[caguy]

I am trying to connect my Uniden VHS to my Garmin 398. I have the in wires connected to the out wires of each unit and vice versa. I even connected the ground wire which I understand is not necessary. They don't seem to see each other. Do you have to run some sort of setup or configuration before they recognize each other?
Any help again is appreciated.

 

[RAD]

Frank
There should be an input positive and negative,output positive and negative on each unit which sounds like you hooked up but remember the output from the radio goes to the input of the GPS and the Output of the GPS goes to the input from the radio also did you go to the set up in the garmin and see if you have to click on something....I think you do and that would be under communications tab in the menu

 

[caguy]

Thanks RAD,
I have the wires correct. I even tried a second set of input/output from the VHS. I'll look through the manual tonight for a switch. I scrolled through the menus on the Garmin and Radio but did not find any switches. I hope setting up the autopilot is easier.

 

[caguy]

Thank you Rad again,
I found in the manual the sub tabs for selecting the NMEA sentences. I will try to find these on the GPS in the morning as it is 12:08 am and freezing outside.
The only thing I am not clear on is do I set the GPS up as a host or a slave?
If that is the only setting for all NMEA devices I assume it will be as a host.
I will also be using with the autopilot.
The radio has a MMSI number that pops up on the screen when the radio is first turned on. If my memory serve me right I believe it can only be changed once (at least that is the way I remember it on my old radio). If that number has been assigned by someone else can I use it and change the data associated with it?

 

[rpwillia]

Couple of things

1. Make sure you have a ground tied in at both ends. When setting mine up (I have a Garmin and a Humminbird) neither worked until I put a redundant ground in at the radio. These signals you are passing are very low voltage and any float can make them undetectable.
2. Definitely need to have the Garmin as host and outputting NMEA instead of the proprietary signal.
3. For the MMSI, this is usually a factory reset - check your manual. It may be simpler to just have the number re-assigned to you. Check with BoatUS.

Here is my wiring diagram. Note that I have the Garmin and the Humminbird pre-wired, but only use one at a time (actually since I got the Humminbird I have not used the Garmin).

 

[Bill Roosa]

GPS host or slave

There is a setup menu to tell each unit what protocol and speed it should use. (I think there are two ports on garmins (one plug for two ports what a dumb idea))

NMEA is a "single talker, multiple listener" network. So which ever unit (autopilot, GPS....) is "doing the talking" needs to be the host. All others need to be slaves. This brings up the issue of who is in charge the autopilot or the GPS???

Now if you had two compleatly seperate NMEA data busses.......... A word to the wise is sufficient.

It is not as easy as it looks, no doubt about it. SeaTalk removes ALL the problems BTW which is probably why it is so popular.

 

[Barnacle Bill]

I bet you have a VHF Marine Radio and not a VHS player. The latter is not NMEA compliant. ;-)

 

[caguy]

Bill, it has all of the connections and the literature says that it is GPS compatible. Whether it is working or not is another question. I have written to the vendor and asked for an exchange.

 

[RAD]

Interesting that when I first hooked my Standard Horizon to a Garmin 182 all worked well then a few years later I hooked up a RayMarine wheel pilot and then learned that it shared the same NMEA wire as the vhf...all is working but like Bill said "This brings up the issue of who is in charge the autopilot or the GPS???
my gps does have 2 comm ports but the other is taken up by the sonar

 

[BLIGHT]

The connection should be the GPS NEMA output should be connected to the VHF NEMA input this same GPS output can be also connected to an autopilot NEMA input since you should have enough signal strength to drive both devices. The VHF NEMA output should be connected to the GPS NEMA input. That connection and color coding is shown on page 92 of your manual. On page 69 last paragraph and pg 70 they explain about setting up the GPS to send NEMA data and also mention the Comm Tab, see page 68, is where you should be able to enable the GPS to send and receive data to and from the VHF and autopilot. I would expect that if all are talking nicely you should expect to see your lats and lons on the VHF. I also believe that the host and slave is only important when two GPS's are connected together.

 

[caguy]

I think all has been set up correctly. I'll post pictures tonight.
Frank