Raymarine question

[diver22]

I have a raymarine C70 plotter connected to the gps aerial and radio via seatalk. I have tried connecting my ST30 depth/speed display to the C70 which after talking to raymarine said would give this information on the C70. When connecting the ST30 to the C70 though the GPS fix is lost. Does anyone have any ideas as to what it could be. All items have a seperate power supply. Many thanks

 

[hightech]

Is the GPS definitely connected via seatalk, as it can also be connected via NMEA. Check the LED flash rate on the GPS. Should be a flash every four seconds for Seatalk.

 

[alan]

I am assuming thay are all connected via Sealtalk??

 

[diver22]

Definitely seatalk, my furuno radar and navtex are connected via nmea

 

[alan]

Are you seure that it is only the GPS data that you are losing?
I would try disconnecting the seatalk from the ST30 and see if the GPS returns.
Then having established 100% that it is the ST30 that is causing the problem, I would think along two lines:
(1.) is the ST30 pulling the bus volts down for some reason, and the NMEA receiver in the C70 is sensitive to this.
(2.) is the ST30 outputting constant data and "hogging" the bus (in which case I would expect you to lose more than just the GPS data)

In addition you could try hooking up the seatalk bus in a different order and see if this helps (it shouldnt make any differene but ...................)

Alan.

 

[diver22]

I have tried the following sequences all with the same outcome-
VHF disconnected from seatalk, ST30 connected - no gps signal
VHF and ST30 connected - no gps signal
One thing i have noticed though is that when i turn on the C70 if my FM radio is playing the volume reduces by over half, could this indicate that the voltage is struggling? I know that the ST30 and C70 come off the same 12v circuit as well as the radar but they all perform correctly until i seatalk the ST30 to the C70 (nmea data not affected)

 

[alan]

I think maybe that you have given (yourself) the pointer. There is no way that the C70 should affect the FM radio except via the power lines.
When you say in your original post "all items have a separate power supply" did you mean the VHF, the C70 and the instrument(s) have separate supplies?? Are you sure they are not supplied via the sealtalk bus?

One trick with seatalk is to treat the bus like a "mains ring" and feed power at both ends ........... i.e. connect the instruments together (radio, C70, ST30) using the seatalk cable and feed the first and the last in the chain with 12v, this sometimes gets over bad power connections.

Alan.

 

[diver22]

Thanks Alan
with your comments i think i may now have hit the nail on the head. The previous owner wired in the ST30, chartplotter and radar all on the same dashboard switch so i think a case of too many amps already being pulled through the wiring. I will rewire for seperate supplies and also boost the seatalk supply at both ends.
Many thanks

 

[alan]

I hope that rewiring solves your problem!!

 

[Jonny_H]

When we fitted Lifetags Raymarine told us that we needed to power our Seatalk bus seperately from the C70. Normally the C70 powers the seatalk - however if you put too much through the seatalk it pulls the voltage too low - therefore you disconnect the red wire from the c70 seatalk and put it to a 12v supply - this will give the seatalk its own power supply and may rectify your issue.

Good luck

Jonny