GPS external vs internal

[Magic]

Presently I have several devices with an internal GPS receiver which I’m using for navigation.

Q1: Should I get an external GPS antenna (tx/rx)? And what are the pros/cons?
Q2: Can I get any GPS antenna or do I need to get one that is compatible with my MFC? Many of the main brands e.g. Raymarine seem to be paired with their MFC.
Q3: I have an NMEA 0183 and NMEA 2000 network. I think the 0183 is just carrying the internal GPS data from memory. Should I just get one that has NMEA 2000? I have a bridge between 0183 & 2000.

Thanks

 

[Skybolt]

External Antenna's are far more accurate and update faster. They also keep a signal much better.

You can use any GPS antenna with any MFD as long as it is either 0183 or N2K. Preferably N2K. Take a look at the Garmin GPS 24xd, it also has a heading sensor in it.

 

[dtfeld]

If you have Raymarine, you can use the RS-150 GPS ($250) or the AR-200 Augmented Reality sensor ($450). Both are a high end NEMA 2000/SeaTalkNG external GPS with access to all the major satellite constellations. The AR-200 adds a heading sensor and if paired with a camera, Augmented Reality capabilities.

Depending on your Raymarine installation (particularly Axioms), it might be a necessity.

 

[Stee6043]

I've got Garmin 742's and the internal antennas seem to be very, very accurate. If I need better than 12" of location precision while boating, I've got bigger problems

 

[dtfeld]

Unfortunately, Raymarine Axioms and Axiom+ have known issues with the internal GPS accuracy based on the placement of the antenna inside the units and where the units are mounted. Some people have issues, others not so much. adding a RS-150 solved the issues and made a major improvement to the system as a whole.

Here was my discussion of the issue on the now defunct Raymarine Forum --> https://forum.raymarine.com/showthread.php?tid=10253

 

[hughespat57]

Let’s break down what we are talking about.
As mentioned the internal antennas will vary in performance and accuracy depending on where the device is mounted.
Most MFC/MFD have NEMA 0182 and 2000 outputs for other devices.
Such as Autopilot or VHF DSC radios. Some VHF DSC radios have built in GPS some don’t. Same issue with placement.

There are two types of “external” antennas. One is just an antenna that feeds the device with a better signal. The MFD will usually have a BNC connector for that. Radios a BNC or an SMA.
These are simple and inexpensive.

Others type is full independent GPS with NMEA outputs.

So options

 

[dtfeld]

Let’s break down what we are talking about.
As mentioned the internal antennas will vary in performance and accuracy depending on where the device is mounted.
Most MFC/MFD have NEMA 0182 and 2000 outputs for other devices.
Such as Autopilot or VHF DSC radios. Some VHF DSC radios have built in GPS some don’t. Same issue with placement.

There are two types of “external” antennas. One is just an antenna that feeds the device with a better signal. The MFD will usually have a BNC connector for that. Radios a BNC or an SMA.
These are simple and inexpensive.

View attachment 160452


View attachment 160451
Others type is full independent GPS with NMEA outputs.



View attachment 160453

So options

Raymarine protecting their bottom line! Installed cost for an axiom/Axiom+ with the RS-150 is about a boat buck cheaper than the higher end models.

Depending in the model, Axiom/Axiom+ requires an active GPS due to no onboard passive connection. You have to get into the Pro and higher versions to be able to utilize a passive antenna (GA-200). Depending in your Sea Ray, the higher end models might not fit (no room at the helm).

 

[Magic]

Thanks for all the feedback.

Ooo…one thing leads to another! I can see a new GPS antenna, a new MFC, which means a new radar…$$$$$.

Boat show is on this weekend too…I’m screwed!!