External GPS Aerial

[Boat Boy]

Hello All, Need some thoughts from the electronic minded people.
I had a navman chartplotter in my boat but had to upgrade it to a raymarine A65 plotter and backbone system when the autopilot was upgraded.
The navman plotter had an external aerial to get the GPS signal. The A65 raymarine has an internal aerial but loses the satellite signal occasionally as it is mounted inside the yacht. So loss of signal means loss of autopilot etc. What I want to know is if all external aerials have the same operating mechanism and are they nmea 0186 or 2000 sensitive. I believe the raymarine aerial just plugs into one of the backbone connectors to get the signal to the GPS, the navman aerial has what looks to be a 2 wire plug.
So the big question can I use the navman aerial and save the $500 on an overpriced raymarine unit? Any thoughts much appreciated.
cheers Ian

[Hydra]

There are 2 kinds of external GPS antennas: "passive" and "active" ones. The passive antennas connect to a coaxial socket on a GPS receiver. The active antennas include a receiver and produce frames which they send to other units, for example over NMEA-0183 or NMEA-2000 links.

The handbook for the A65 plotter (http://www.raymarine.com/WorkArea/Do...t.aspx?id=4792) says (page 19) that the RS 12 contains a GPS receiver. On page 16, it shows the socket for the GPS, with 6 connectors.

So, if your Navman aerial cable termination is different from the raymarine socket, you will have to buy the RS 12 active antenna.

I hope this helps.

Alain

[rwidman]

Unlike VHF antennas, GPS antennas are not interchangeable. Buy and install the one that's designed to work with your system.