Topic: gps antenna not outputting NMEA 0183

[schwa]

All,

Great board! I just installed my 798c SI.

I have not been able to get any signal off the 'pigtail' from the gps antenna. I am trying to connect it to my radio for DSC functionality. I have the menu setting in the unit to output gps, but does that even affect the pigtail?

Anyway, if anyone has any idea why the antenna would not be outputting the NMEA 0183 data, let me know. Is it possible that that part of the antenna can be bad while the antenna still provides good gps data to the 798 unit?

thanks

[RGecy]

schwa,

Welcome to the forum.  Which wires in the pigtail are you using?  You should be using the White (+) NMEA Data Out and the Black (-) Ground. 

Robert

Details NMEA Pigtail Wiring Diagram

NMEA Pigtail Wiring Diagram

[Jolly Roger]

Hello Schwa and welcome to the forum!

I'm not sure what NMEA sentence you need to get the desired information, but Robert wrote something about the outputted NMEA sentences here:

http://forums.sideimagingsoft.com/index.php?topic=10.msg13#msg13

I wrote something about the wiring here:

http://forums.sideimagingsoft.com/index.php?topic=711.0

I hope this will provide you with the needed information.

Good luck and best wishes from Germany

Harry

[Trytoofish]

Do you have nmea turned on in  the menu?

[RGecy]

It may also be that the radio will only recognise the $GP NMEA data.  Humminbird outputs $IN string.  I believe you can get the $GP string direct from the GPS puck by using the black and the green wire.  However, I think this is only on newer GPS pucks.

I know Greg had posted on this somewhere on the forum.

Robert

[Humminbird_Greg]

Depending on which version GPS Receiver he has; the Green wire may be available in the NMEA pigtail.

[schwa]

Yep, I had it connected to the white and black from the 'pigtail' and have NMEA output turned on. The radio worked when hooked to my older lowrance gps, but nothing from the humminbird. I also tried connecting the NMEA output from the humminbird to the NMEA input on my lowrance and was not getting any data.

Question is, can the gps puck be sending good signal to the humminbird unit and not be sending it over the NMEA pigtail? It seems it is, and I really don't want to uninstall the gps puck to send it in, that would be a real pain.

[RGecy]

schwa,

Do you have a green wire in the pigtail?  If so did you try it with that hooked up?

Like I said, the HB NMEA output is not your standard $GP prefix and uses the Integrated Navigational Device prefix of $IN.  So instead of $GPGGA a sstring will say $INGGA.  Your unit may not recognise this format. 

Here are the NMEA output sentences HB generates, grouped by type:

GLL - Geographic Position - Lat/Lon
GGA - GPS Fix Data
RMC - Recommended Minimum Specific GNSS Data
VTG - Course Over Ground and Ground Speed
ZDA - Time and Date

APB - Autopilot Sentence B
BWR - Bearing & Distance to Waypoint - Rhumb Line
RMB - Recommended Minimum Navigation Information

DPT - Depth

MTW - Water Temperature

The sentences go out in the following order:

Second 1: DPT, APB, BWR, GLL, VTG, MTW
Second 2: DPT, RMB, RMC
Second 3: DPT, APB, BWR, GGA, ZDA, MTW
Second 4: DPT, RMB, RMC

Have you tried to hook the pigtail up to a computer and capture the NMEA output?  Its fairly easy to do and you can log it on the computer with Hyper Terminal.

Good Luck,

Robert

[Humminbird_Greg]

schwa,
The NMEA Output signal actually goes through the unit itself (that is why the NMEA Output menu has to be set to “On”).  It is possible that the GPS Receiver could be outputting the NMEA data to the unit but the unit not pass it along.  The only way to know for sure would be to test another unit on your set up and have it work or not.  Try those things that Robert suggested and get back to us.