Chart plotter

Big dave · Posted: Mon Sep 04, 2023 5:24 pm Post subject: Chart plotter

Does anyone know if an external antenna is required on the new chart plotter’s/fish finders ? It seems none of the new plotters come with an external antenna. Do the new ones just receive signals through the roof of a C-Dory ?
Thanks
Dave
Raven Dancer

srbaum · Posted: Mon Sep 04, 2023 5:52 pm Post subject:

Dave,
New chartplottters have built in GPS antennas, so the newer technology has precluded the need. My older Raymarine has a cabin top GPS antenna, where as my last several Garmin's have not had one nor needed one.
I have chart plotters on my other boats as well and none of them have external antenna.

itiming · Posted: Mon Sep 04, 2023 7:44 pm Post subject:

If you have radar, a heading sensor improves the radar overlay screen's use. Installation is usually done via a NEMA 2000 network between the MFD and the heading sensor. The boat's orientation then shows correctly and the radar overlays accurately over the chart.

ssobol · Posted: Mon Sep 04, 2023 9:02 pm Post subject:

The last two chartplotters I had incorporated internal GPS. They could also use NMEA GPS from the appropriate sensor. The internal GPS seemed to work fine with the chartplotter mounted on the CD22 helm. Since I already had a NMEA GPS receiver (roof mounted) on the network I used that.

Flashyfish · Posted: Tue Sep 05, 2023 10:37 am Post subject:

I have two of the Simrad Go9 chartplotters with internal GPS antennas. They function perfectly and have had zero problems with losing satellite contact.
Proven very reliable when navigating during fog or darkness in combination with radar.
I might upgrade at some point and add the electronic compass sensor.

thataway · Posted: Tue Sep 05, 2023 3:12 pm Post subject:

Many of the earlier GPS had external antennas. Newer technology, both on the transmitting end (satellites) and the MFD with more sensitive receivers, along with the "Selective Availability" turned off, makes the GPS more accurate. Many now can use the "Galileo" "The EU system; "Glonass" the Russian System; and "BeiDou" Chinese system. Also the refresh rate has come down to 10 hz. Also there is the Real Time Kinematics, such as Point one, which gives accuracy in the cm range.

All of these will work in vehicles and thru normal house roofs etc, let alone the fiberglass layer of a C Dory.