Raymarine Axiom 7 with external GPS

[SorinCT]

Hello!
I am having some issues with GPS signal and am looking for potential solutions. I have a Raymarine Axiom 7 at the helm (has internal GPS) but the GPS signal is weak and drops frequently. Some of the reasons i identified so far are: flush mount panel contains aluminum and may block signal, shading from PV array (also aluminum + stainless) and poor antenna capabilities for Axiom 7 (as per other owners feedback and tests in the local marina).

Before attempting to modify unit's location and mounting plate, i am researching what can be done in terms of externa GPS antenna. My best guess is that the coax or NMEA signal needs to get injected into the SeatalkNG network, either by a gateway or something similar. Is there any DIY solution to use non-Raymarine parts for this?

Current price for compatibe RS-150 antenna is 300 $, 60$ for SeatalkNG T-connector and backbone cable, plus shipping. 400$ to address these kind of problems is a bit too much seeing as equipment is almost new.

Network currently also has Raymarine Ray50 with internal GPS antenna, mounted at the nav console which is suffering from same issue with mostly unreliable signal.

Has anybody tried any other GPS antenna or arrangement to improve GPS signal?

 

[KompetentKrew]

Do you have a SeatalkNG / NMEA2000 network already?

The data sentences carried over NMEA 2000 networks are mostly standardised (and SeaTalkNG is mostly NMEA 2000 with a funny connector), so any GPS which can output NMEA 2000 will do.

 

[SorinCT]

Yes i already have a network. I have also Ray50 VHF with internal GPS and AIS700 with external GPS antenna which does not forward the GPS data to the network (coax cable connected to AIS700).

 

[KompetentKrew]

If you connect a laptop to the AIS700 and use the ProAIS2 software then there's a checkbox allowing it to forward GPS data to the NMEA 2000 network.

Presumably the AIS already sends the AIS data over NMEA 2000 to the Axiom, so then it'll just be a case of it being recognised automatically OR you'll select a different data source for GPS in the Axiom's menus.

(I think the connector on the AIS700 is NMEA 2000, not SeatTalkNG, by the way. I wouldn't be surprised if it's the same on the Axiom.)

I'd see if that works to start with, then if you want you can add the Ray50 VHF to the network. See the NMEA 2000 essentials PDF and discussion of backbone and termination in this previous thread.

The coax is a red herring - the only thing that goes over that is radio transmissions. It's irrelevant to GPS.

 

[SorinCT]

VHF50 is already on the network, recognised as a source for GPS but signal si as or maybe weaker than Axiom.
I will try to tinker again with the ProAIS2 software to see what i can do.