I have received a lot of questions recently concerning the new Point 1 antenna. The main difference between these and a LGC 4000 is their built in 10 Hz heading sensor which provides chart stabilization and radar overlay, plus accurate course over ground indication even at low speeds. Lowrance did not invent the heading sensor with this device, but they are offering an economical alternative. The Point 1 mounts directionally to keep track of the bow orientation.
What will be different on the water? With a LGC4000 or the HDS internal antenna and a "Heading Up" chart selection, when you begin reversing the chart will spin. As you back up with a Point 1 antenna the chart orientation will not change because the bow of your boat is still pointing in the original direction. Locating waypoints is easier, but I would still throw a buoy.
Point 1's work with the same units as LGC 4000's. The HDS Gen2's and Touch units operating with the new Version 2.0 software have the ability to initiate a calibration sequence from the Device List-Details. On Gen 1's or older 520's, etc., calibrate the antenna by unplugging it from the NMEA backbone then plug it back in. Immediately following this begin turning you boat in a slow circle (2-3 minute). The completion of one circle initiates the calibration process, and a second should complete it.
HDS Gen2 and Touch units running Version 2.0 software also have GPS damping and filtering features that will not be present in HDS Gen1 or older units, but the antennas will work fine.
You cannot run two Point 1 antennas on a single NMEA network because they do not contain a hard-coded identifier for the heading sensor, like the more advanced electronic compasses do. If another heading sensor appears on the NMEA backbone they disable themselves to avoid conflicting data. I recently installed 2 on one boat, but it required a separate NMEA backbone to a dedicated charting unit on the console. The forward mounted Point 1 was included in the main NMEA backbone with 4 other locators. The customer absolutely wanted 2 of them.
Point 1 antennas contain a very sensitive electronic compass in the housing. Therefore it is very important to mount the antenna away from anything that emits a magnetic field like trolling motors, VHF antennas, radars, even outboard wire looms. Lowrance recommends 20" of separation but my experience indicates that may not be enough. I debugged a pro tournament boat 2 weeks ago where the chart page looked like Martians had taken over...everything was spinning randomly. The antenna was mounted right on the nose of the boat and the magnetic force of the trolling motor hijacked the gyro. It took 3' of separation to obtain proper operation. Nothing like an extra 3/4" hole in the boat from the original mounting location.
The internal HDS GPS antennas are fine for positional accuracy and can be selected over the GPS portion of the Point 1 antenna in Data Sources. The heading sensor in the Point 1 provides chart stability. It selects individually under Vessels, so you can run any antenna in the boat on the NMEA network, even a LGC 4000 on the bow, in combination with the Point 1 heading sensor. If you want advanced directional stability like auto pilots often require, look into a Maretron SSC200.
The SSC200 is a 3-axis magnetometer, a 2-axis accelerometer and a rate gyro. The outputs of all these sensors combine in a software algorithm running on an internal microcontroller to give high precision and extremely stable heading information. Without a Maretron display, the calibration is a bit cumbersome, but it can be controlled from a PC using a terminal emulator. Many of the barge company work boats on the Mississippi contain these devices in combination with their radar.