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.

 

[Irish Rover]

My relatively new to me boat has an Axiom 9 plus an Axiom 7 and for the last week or so it is very slow to acquire a GPS fix. As best I understand it, the 2 units are paired, and automatically decide which of internal GPS feed.to use. When it has failed to get a fix I've played around with the data source settings and switched between the 2 but it seems to have made no difference. I do eventually get a fix - longest wait approximately 30 minutes - and once it has a fix it doesn't seem to lose it again until powered down. From what I've been able to learn online this does seem to be an inherent issue with the Axioms. I'm planning to connect an external GPS antenna but it will have to wait until my son comes to visit in the autumn to figure out what bits and bobs we need.

 

[RAFFY]

I had the same issue for 2seasons. Eventually bit the bullet and purchased RS150 antenna and it has transformed the kit. Just a few seconds to get a fix and never drops out. Feel a bit misled by Raymarine as the in-built antenna is obviously not up to the task but thats life.

 

[geem]

My relatively new to me boat has an Axiom 9 plus an Axiom 7 and for the last week or so it is very slow to acquire a GPS fix. As best I understand it, the 2 units are paired, and automatically decide which of internal GPS feed.to use. When it has failed to get a fix I've played around with the data source settings and switched between the 2 but it seems to have made no difference. I do eventually get a fix - longest wait approximately 30 minutes - and once it has a fix it doesn't seem to lose it again until powered down. From what I've been able to learn online this does seem to be an inherent issue with the Axioms. I'm planning to connect an external GPS antenna but it will have to wait until my son comes to visit in the autumn to figure out what bits and bobs we need.

My Axiom 12 is mounted under the sprayhood and gets a GPS fix rapidly from its own inbuilt GPS. It has a good clear view of the sky. Could this be the issue?

 

[Greg2]

We have an Axiom 12 in our wheelhouse and I wondered whether an external GPS would be required but it has been absolutely fine with no issues getting a signal. We also have a smaller Axiom on the fly that is networked so perhaps they do use the best signal but the 12 still picks up a position okay when the fly isn’t switched on.

 

[Irish Rover]

Both of mine are on the flybridge and I do have a hardtop but I don't believe this is the issue. There are many reports on the Internet of problems with GPS on the A7 and A9 but I can't say I recall seeing reports of problems on the A12's.

 

[Grumpydev]

Maybe it is something specific to the smaller ones, I switched to using the internal one on our 12 a few months back and it seems fine, we do have an external on the radar arch but its an older one and suffers from the rollover date issue.