> For the complete documentation index, see [llms.txt](https://docs.premium-positioning.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.premium-positioning.com/guides/hemisphere-phantom-40.md).

# Hemisphere Phantom 40

These steps connect a Hemisphere Phantom 40 / P-series OEM to the Premium Positioning correction network over NTRIP, using Host NTRIP client / receiver commands. They assume you already have your NTRIP credentials.

### Before you start

* Your NTRIP username and password, from your Premium Positioning welcome email or your account on the customer portal.
* Host NTRIP client / receiver commands.
* A working internet connection on the controller or phone.
* A clear view of the sky at the point you are measuring.

### Network settings

These are the same for every Premium Positioning customer. Only your username and password are unique to you.

* Server or host: rtkpremium.xyz
* Port: 2101
* Mountpoint: COMMON
* Protocol: NTRIP

### Steps

1. Understand the architecture: Hemisphere Phantom 40 and Eclipse P-series (P326/P327) OEM boards run the Athena RTK engine and accept RTCM3 corrections on a serial port; they do not include a built-in NTRIP TCP/IP client. So your integration host connects to our NTRIP caster, pulls the RTCM3 stream, and injects those bytes into the board's correction serial port. (If your product wraps the board with a module that adds a network NTRIP client, enter the caster details directly there - the caster values are identical either way.)
2. Get your NTRIP login ready: Use the NTRIP username and password from your welcome email - unique to your account; never share or reuse someone else's. If you can't find them, contact support before continuing.
3. Point your NTRIP client at our caster: In your host NTRIP client (or the network module's NTRIP settings), enter EXACTLY: Host/Server rtkpremium.xyz, Port 2101, Mountpoint COMMON, Protocol NTRIP. Then enter YOUR OWN username and password. These four caster values are the same for every customer; only the credentials differ.
4. Connect to the board with a terminal: Connect a terminal/console to one of the board's main serial ports (A, B or C) using PocketMax, SLXMon, or any serial terminal. Note the default baud - on P-series commonly 115200 on the main ports; confirm against your data sheet. Hemisphere proprietary commands begin with '$J' and end with .
5. Confirm the board is tracking satellites: Turn on a position message to watch status: send $JASC,GPGGA,1 to output GGA at 1 Hz on the current port. With the antenna outdoors and clear sky, you should see a valid position (GGA quality 1 = autonomous) within \~a minute before applying corrections.
6. Pick and configure the correction input port: Decide which port receives the RTCM3 stream. Match its baud to your host with $JBAUD - e.g. $JBAUD,115200 (current port), or $JBAUD,115200,OTHER (opposite main port); add ,SAVE to persist. Note: on P326/P327, Port D is a dedicated correction-input port fixed at 9600 8-N-1; for a general NTRIP/RTCM3 feed, prefer a main port (A/B/C) so you control the baud.
7. Tell the receiver to use external corrections from that port: Use $JDIFF to select the external-correction source: $JDIFF,THIS (the port you're typing into), $JDIFF,OTHER, or $JDIFF,PORTA/PORTB/PORTC. Example: corrections into Port B → $JDIFF,PORTB. Add ,SAVE to persist, e.g. $JDIFF,PORTB,SAVE.
8. Start the RTCM3 stream from your host: Have your host NTRIP client connect to rtkpremium.xyz:2101, mountpoint COMMON, authenticate, and write the received RTCM3 bytes straight to the chosen serial port - raw pass-through, no reformatting. Match the host's serial settings (baud, 8-N-1) to the board.
9. Send your approximate position to the caster (if required): NTRIP casters typically expect a periodic NMEA GGA from the rover. Most host clients read GGA back from the receiver automatically. If your client needs a GGA feed, route the board's GGA output (from $JASC,GPGGA,1) to it; or use the client's manual/fixed-position option.
10. Verify corrections are arriving: Your NTRIP client should show a steady inbound data rate from the COMMON mountpoint, and the board's differential status should show corrections in use. Query the source with $JDIFF, and enable the RTK status message with $JASC,PSAT,RTKSTAT,1 to see correction age and engine state. Age should stay low (a few seconds).
11. Watch the GGA quality climb to RTK: In the GGA stream the quality indicator progresses: 1 = autonomous, 2 = differential, 5 = RTK Float, 4 = RTK Fixed (standard NMEA fix-quality codes). Convergence to Fixed typically takes seconds to a couple of minutes depending on baseline and sky view.
12. Confirm RTK Fixed: You have a working setup when the GGA quality reads 4 (RTK Fixed / RTK integer fixed) with low correction age and a stable cm-level position. Persist your configuration with $JSAVE and wait for SAVE COMPLETE before power-cycling, so the receiver reboots already configured.

### If the fix will not hold

Command names ($JDIFF, $JBAUD, $JASC,GPGGA, $JASC,PSAT,RTKSTAT, $JSAVE) are from the Hemisphere GNSS Technical Reference and the Eclipse P326/P327 Integrator's Guide and apply across Eclipse/Athena-based boards, but exact ports, default baud rates and available correction sources vary by board model/firmware - verify against your unit's data sheet. These OEM boards take RTCM3 on a serial port and do not include a built-in network NTRIP client, so a host application (or an integrating network module) performs the NTRIP connection and pipes RTCM3 to the receiver.

For more, see RTK corrections troubleshooting and Fix inconsistent RTK accuracy on site.

### Need help

Support is available 24/7. Include your receiver model, the mountpoint, the solution status, and the correction age when you get in touch.