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A68 reported -.- for Speed - Printable Version

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A68 reported -.- for Speed - 100333624 - 05-24-16 06:28 PM

Hello I’m new to this forum and looking for some help/guidance with me Raymarine unit.

I purchased a Raymarine A68 unit with Navionics Gold package, really nice little unit it seems very loaded for what it is that’s for sure!

I’ve fooled around with it twice so far on the lake as I still need to get used to it. I couldn’t get the speed settings to show up as I am navigating in the chart mode, but I figured it out finally but it’s not showing any speed?? It just shows -.- KPH…

I read in the manual that I should use the “LOW” setting in the COG/SOG Filter and that’s what I selected. This is mentioned on page 106 of the manual located here: https://www.svb.de/media/501821/pdf/manual_en_2014-12-05.pdf

Furthermore on page 115 it mentions Selecting the Sonar Transducer and Speed Transducer? When I follow the steps for the Speed Transducer I don’t get a selection for speed, only Depth and Temperature if I recall correctly.

I thought it was all in the GPS since it mentions again on page 106 under COG/SOG Filter:

"The COG/SOG filter averages the velocity vectors to compensate for the oscillating motion of the vessel, giving a clearer indication of the vessel’s course and speed.

The filter does not affect the calculation of your receiver’s reported position. The velocity vectors calculated from the signal provide an instantaneous measure of speed and direction of the receiver. The COG and SOG can therefor seem erratic under certain conditions. For example, when a vessel is moving slowly through rough seas, the receiver moves from side to side as well as in the direction of travel.

Slow moving vessels, or vessels sailing in rough seas will benefit from a high setting, whereas a power boat that can quickly change speed and direction will benefit from a low setting."

Now my question is how is this unit supposed to read my speed? If it is as it says above then it must be through GPS therefore not needing a transducer? I was told the GPS is in the face of the unit itself (the screen) so I can’t see why it needs a separate transducer? If it is through a “speed transducer” then why don’t they come with it to begin with??? Even cheap fish finders have GPS speed or transom mounted paddles or tubes for reading speed, yes they aren’t as accurate as GPS but at least it’s something? Also if it is through a transducer, then my next question is how accurate is it?

Hopefully I’m just missing something simple.

Also if it helps, it does show my vessels position as it moves, it is very sensitive I can tell, but through 24km of boating it didn’t read speed at all, not even 0.1 just -.-KPH. So something tells me there is something missing here?

Anyway if anyone can help out it will be GREATLY appreciated! Thank you and sorry for venting in this long post!!


RE: A68 HELP! - Chuck - Raymarine - Moderator - 05-25-16 08:19 AM

Welcome to the Raymarine Forum Nick,

Please click here to view a FAQ addressing this subject. CHIRP (conical) / DownVision transducers used with the ax8 MFDs, eSx8 MFDs, and CP100 do not feature speed through water sensors. Correspondingly, there will be no option to select a transducer or speed transducer for CHIRP (conical) / DownVision fishfinder sonar. As CHIRP (conical) / DownVision Transducers do not feature speed through water sensors, the SOG rather than Speed data item should be displayed unless the system has been interfaced to another speed through water sensing product (ex. CP370 w/compatible depth/speed/temp fishfinder transducer, i50 Speed Instrument w/speed/temp transducer, etc.). Regarding the GPS COG/SOG filter, the overwhelming percentage of users simply leave this configuration item in the Medium settings producing very satisfactory results in a properly installed and properly functioning GPS sensing device.

RE: A68 reported -.- for Speed - 100333624 - 05-26-16 05:22 PM

Yes it works!! Its kind of all over the place but it works, maybe will be better in the water as I tried it in my garage so signal isn't the greatest but it definitely works. Thanks Chuck!!!!


RE: A68 reported -.- for Speed - Chuck - Raymarine - Moderator - 05-27-16 07:45 AM


Should you have reviewed the FAQ referenced within my initial response, should the MFD be installed in a location which does not afford it an unobstructed view of the skies overhead, then the GPS signal strength may be reduced, thereby resulting in a high HDOP which in turn will in turn be reflected error in position, COG, and SOG. Operating the equipment with the boat inside one's garage, boat house, etc. will have similar GPS performance degrading effects.