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Old 03-02-2015, 04:54 PM   #1
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RM SOG help

My SOG reading isn't stable at all. It varies from 6 kt. to 10 kt. at tenth of a kt. increments in a matter of seconds. The readings are being taken in calm conditions. The equipment is all Ray Marine; e7D and auto pilot head unit. Has anyone out there had this problem. The speed is being received from the internal GPS on the e7D. I compared it to a speed app on my phone; phone read a constant 7 kts. Any advice? And no, I'm not going to use my phone for speedometer. lol.
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Old 03-02-2015, 04:57 PM   #2
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Quote:
Originally Posted by dhiggins View Post
My SOG reading isn't stable at all. It varies from 6 kt. to 10 kt. at tenth of a kt. increments in a matter of seconds. The readings are being taken in calm conditions. The equipment is all Ray Marine; e7D and auto pilot head unit. Has anyone out there had this problem. The speed is being received from the internal GPS on the e7D. I compared it to a speed app on my phone; phone read a constant 7 kts. Any advice? And no, I'm not going to use my phone for speedometer. lol.

Is it in a covered location? You may need an external antenna.
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Old 03-02-2015, 05:11 PM   #3
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On most GPSs, you can adjust the time the GPS calculates the SOG and the POS. Go into your menu. Adjust the time (s) up and see what happens. You should get a more consistent SOG.
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Old 03-02-2015, 05:21 PM   #4
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I tried a few things in the menu with no luck..may have to dig deeper....but I suspect it might be location of the internal antenna.

OP, is it in cabin or flybridge? Mine is at lower helm.
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Old 03-02-2015, 05:30 PM   #5
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Maybe this is not your issue, but is it possible your settings have SOG coming from paddle wheel, not from GPS?
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Old 03-02-2015, 07:28 PM   #6
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I this a new problem? Has it been working OK previously?
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Old 03-02-2015, 07:31 PM   #7
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Reading is coming from e7D which is on the FB with a clear view of the sky. RM has three speed settings, I've tried all with no improvement. A external antenna may solve the problem. But, chart, heading, etc. works OK. So, I am thinking the GPS and location isn't the problem. But I may be wrong.
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Old 03-02-2015, 09:49 PM   #8
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Have you contacted Ray Marine?
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Old 03-02-2015, 09:53 PM   #9
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Old 03-03-2015, 04:23 AM   #10
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select proper source

The speed reading that you receive through your GPS is known as speed overground (SOG), make sure that you are displaying the proper data for the source of your speed information. In the databox you have this information you do not want to select "Speed" as the type of data. You want to select "SOG". "Speed" requires some form of speed transducer to collect the speed data. "Speed" is your true speed through the water and tends to differ from the SOG measured from GPS coordinates.

Keep in mind that the newest internal GPS receivers are updating at 100Hz and the numbers will change more quickly than before. You should also enable WAAS and verify low HDOP (good GPS signals from many satellites).

You should also make sure the software is the latest version. Good Luck.
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Old 03-09-2015, 11:11 AM   #11
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Great news; I installed a new external GPS antenna and the problem is solved. It also seemed to improve the performance of stuff like the chart, etc. Money well spent.
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