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Amplifier for NMEA out connection

Old 11-11-2002, 11:08 AM
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Default Amplifier for NMEA out connection

I recall seeing someone mention they ended up having to install some type of amplifier (made by Raytheon) to get their GPS to properly output NMEA data to other devices. I performed a search but couldn't come up with anything.

I'm attempting to interface a Furuno LS6000, a Garmin GPS48 and a Standard Horizon Intrepid LE. I have all connections in place and am 100% confident they are correct (verified by speaking with Garmin tech support). The NMEA out of the GPS, and the NMEA in of the sounder and VHF are all connected to a mini-bus bar. When I test the connection from the GPS with a voltmeter while connected to the bus bar, I get no reading. When I remove the connection and test the ring terminal on the end of the wire, I get fluctuating voltage to around 1.6V. When I hold the NMEA out from the GPS together with the NMEA in of the sounder, data is correctly transferred and position, bearing, heading, waypoint, etc. shows up on the Furuno screen. When I do the same with the NMEA out from the GPS and the NMEA in of the VHF together, I get nothing. My guess is that the NMEA out signal from the GPS is simply not strong enough to provide the VHF with what it needs, nor to provide both devices through the bus bar for that matter. The extra load, drowns out the signal and hence no voltage present when all are connected to the bus bar.

Am I on the right track?

Thanks.

Brian
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Old 11-11-2002, 12:37 PM
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Default Amplifier for NMEA out connection

That Garmin will easily feed a sounder and a radio. Check the setup on the radio to make sure it is able to accept the data. The Garmin should be able to provide data to at least 3 devices and usually 4 without any problem at all.

Thom

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Old 11-11-2002, 01:12 PM
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Default Amplifier for NMEA out connection

Thanks Thom. I've also sent an email to Standard tech support. I will double check continuity of cable to the radio as I did have to lengthen it a bit. As usual, the manual didn't give any information other than the wiring scheme.

Brian
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Old 11-11-2002, 06:35 PM
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Default Amplifier for NMEA out connection

Through no fault of my own. [img]/infopop/emoticons/icon_smile.gif[/img]

The cable provided by S-H is a dual function that incorporates brining in NMEA data as well as the necessary connections for an external speaker.

Continuity test revealed no circuit between NMEA in + pin in the connector to what should be the corresponding ring terminal on the opposite end. But continuity between external speaker + and - pins with what should be the corresponding ring terminal for NMEA in +.

Continuity also test revealed no circuit between NMEA in - pin in the connector to what should be the corresponding ring terminal on the opposite end, but continuity between external speaker + and - pins with what should be the corresponding ring terminal for NMEA in -.

So, all this tells me something is FUBAR in the connector.

I know my wire extensions aren't the problem. All are clean, soldered joints, sealed w/ liquid electrical tape and adhesive heat shrink, and I color matched the wire used for the extensions to the wires coming out of the adapter cable.

Time for S-H to send me a new adapter. Will be calling them tomorrow. The radio is still under warranty so there had better not be any disputes.

Brian
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Old 11-12-2002, 06:20 AM
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Default Amplifier for NMEA out connection

I have a Lowrance Global Map 1600 interaced with a Furuno 600L, Icom M502 VHF, JRC 1500 Radar, Simrad AP 12 Autopilot and a Lowrance DGPS antenna. All receive NEMA output from the GPS. I've noticed lately that I lose DGPS when all are turned on but if I turn off the Furuno 600L, the DGPS signal immediately comes back on.

Do I need a NMEA amplifier? I never noticed it doing this before, it has worked fine for about a year. I was thinking that maybe it's corrosion on the wiring but everything is installed in NavPods except the VHF. Any ideas?

Regards
Randy
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Old 11-12-2002, 07:06 AM
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Default Amplifier for NMEA out connection

Randy,

I'd just bet that your assessement that the problem is being caused by corrosion is absolutly correct. A Navpod may slow down the process by protecting the wireing but it won't stop it. You know the routine, solder, sealer, shrinkfit.

By the way, I'm really a bit suprised that you don't loose everything and then regain everything when one, any one, of the devices is turned off.

Thom

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Old 11-12-2002, 12:48 PM
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Default Amplifier for NMEA out connection

Just got off the phone with the tech. rep. at Standard-Horizon and a new accessory cable is on the way. He sounded amazed that I already had everything wired perfectly and all GPS output settings were correct. The guy was pleasant to deal with and gave me his direct line to follow up once I receive the cable.

Thumbs up for Standard-Horizon tech support!!!
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