# No GPS signal is being received from iGrade.

<span dir="ltr" style="font-size: 14pt; font-family: Helvetica, sans-serif; font-weight: 400;">**Symptoms**:</span>

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">Tractor position icon not appearing on map-screens.</span></span>

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">‘GPS info’ button in the bottom right of map-screens is red.</span></span>

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">In the ‘Settings’ window there are no characters streaming into the ‘Serial port raw data’ window in the ‘GPS Port Settings’ tab.</span></span>

<span style="font-family: Helvetica,sans-serif;">  
</span>

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt;">**Symptoms of incorrect baud**:</span></span>

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">Incorrect baud rate settings are identifiable by viewing the incoming data in the window provided in the GPS setting tab.</span></span>

<span style="font-family: Helvetica,sans-serif;">  
</span>

<span style="font-family: Helvetica,sans-serif;"><span dir="ltr" style="font-size: 14pt; font-weight: 300;">Good data looks like normal text, as below.</span></span>

![](https://docs.t3rra.com/uploads/images/gallery/2025-03/scaled-1680-/8xdwbuh6urrssalzpnujuabzc95ikkmyqg-png.png)

<span style="font-family: Helvetica,sans-serif;">  
</span>

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">Incorrect baud looks like:</span></span>

![](https://docs.t3rra.com/uploads/images/gallery/2025-03/scaled-1680-/fchqe5goxjjwkllvwo7oaz730xkrelj6ow-png.png)

<span style="font-family: Helvetica,sans-serif;">  
</span>

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 400;">**Causes**:</span></span>

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">The port for the GPS to T3RRA software may be closed.</span></span>

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">Signal sharing is causing iGrade to lose Gps</span></span>

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">Drivers for tablets serial port or USB-to-serial port may not be up-to-date.</span></span>

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">Cables may not be seated correctly.</span></span>

<span style="font-family: Helvetica,sans-serif;">  
</span>

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 400;">**Solutions**:</span></span>

1. <span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">Ensure all Windows updates are performed.</span></span>
2. <span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">Open the GPS info screen by pressing on the GPS button in the bottom right of the Collect or Apply step. Confirm that you have an RTK GPS signal and that the Open Port button is grayed out.</span></span>
3. <span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">Ensure Signal Sharing is disabled in Autotrac settings</span></span>  
    <span style="font-family: Helvetica,sans-serif;"><span dir="ltr" style="font-size: 14pt; font-weight: 300;">![](https://docs.t3rra.com/uploads/images/gallery/2025-03/scaled-1680-/jdtiasznw7yxw1llflr6psy-htccdgichg-png.png)![](https://docs.t3rra.com/uploads/images/gallery/2025-03/scaled-1680-/axcoa5py0yixepvfx2ck2gwldcrnkq03pa-png.png)</span></span>![](https://docs.t3rra.com/uploads/images/gallery/2025-03/scaled-1680-/wnkquzhlphu9pjatsd02oz6vb1rp-qjuow-jpg.jpeg)
4. <span style="font-family: Helvetica,sans-serif;"><span dir="ltr" style="font-size: 14pt;">Confirm USB-to-serial cable’s driver is up-to-date if applicable (refer to 'Access to the port ‘COM X’ is denied’. for instructions on how to update driver)</span></span>
5. <span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt;">Confirm harnessing is correctly installed using AE3166 to connect T3RRA to iGrade app controller or AE3070 to T into receiver for surveying without iGrade.</span></span>
6. <span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt;">Perform a continuity check on the iGrade harness to make sure the pin configuration is correct and the cable is not damaged.</span></span>
7. <span style="font-family: Helvetica,sans-serif;"><span dir="ltr" style="font-size: 14pt; font-weight: 300;">Check settings in both iGrade and T3RRA (iGrade and T3C need identical Baud Rate):</span></span><table style="border: none; border-collapse: collapse; table-layout: fixed; width: 468pt;"><colgroup><col></col></colgroup><tbody><tr style="height: 0pt;"><td style="padding: 5pt; overflow: hidden; overflow-wrap: break-word; text-align: center; background-color: rgb(250, 197, 28); border: 1pt solid rgb(255, 255, 255);"><span style="font-family: Helvetica,sans-serif;"><span style="font-size: 13pt; font-weight: 400;">IMPORTANT: </span><span style="font-size: 13pt; font-weight: 300;">When using T3RRA Products with iGrade you must configure the serial settings in “</span><span style="font-size: 13pt; font-weight: 400;">iGrade Settings</span><span style="font-size: 13pt; font-weight: 300;">”. You only need to configure the serial port in “</span><span style="font-size: 13pt; font-weight: 400;">Receiver Settings</span><span dir="ltr" style="font-size: 13pt; font-weight: 300;">” if you are connecting directly to the StarFire (as you might do when you are surveying in a Gator for instance).</span></span>
    
    </td></tr></tbody></table>

<div align="left" dir="ltr" id="bkmrk--6" style="margin-left: 0pt; font-family: Helvetica, sans-serif;"></div><span style="font-family: Helvetica,sans-serif;">  
</span>

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300; text-decoration-skip-ink: none;"><u>In iGrade UCC1:</u></span></span>

- <span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">Select Main Menu</span></span>
- <span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">Select Control Selection</span></span>
- <span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">Select Serial Port Setup</span></span>
- <span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">Baud Rate – 38400</span></span>
- <span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">NMEA – GGA, GSA</span></span>
- <span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">NMEA Rate – 5 Hz</span></span>
- <span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">Set Last Altitude - Off</span></span>

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">Power cycle the UCC1 controller (note that the controller may have been connected to constant power, and so a key off/on may not be sufficient to power cycle the controller).</span></span>

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;"> </span></span>

<span style="font-family: Helvetica,sans-serif;"><span dir="ltr" style="font-size: 14pt; font-weight: 300; text-decoration-skip-ink: none;"><u>In T3RRA (using iGrade UCC1):</u></span></span>

- <span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">Open T3RRA program and go to Settings &gt; GPS Port Settings</span></span>
- <span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">Set 'COM Port' to the correct port</span></span>
- <span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">Set Baud rate to 38400</span></span>
- <span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">Select Ok button</span></span>

<span style="font-family: Helvetica,sans-serif;">  
</span>

<span style="font-family: Helvetica,sans-serif;">  
</span>

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 18pt; font-weight: 400;">**Testing Serial harnessing.**</span></span>

<span style="font-family: Helvetica,sans-serif;">  
</span>

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">The most reliable way to confirm correct serial port harnesses operation when using T3RRA Products is to utilise the Port data window and use a testing method called Serial Loopback.</span></span>

<span style="font-family: Helvetica,sans-serif;">  
</span>

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">A loopback test can verify the operation of serial communication by sending and receiving data from the same serial port. It can show problems in the serial port, the cable, or the software generating the messages without having to connect to third party hardware.</span></span>

<span style="font-family: Helvetica,sans-serif;">  
</span>

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt;">**VERY CAREFULLY!**</span><span style="font-size: 14pt; font-weight: 300;"> connect the transmit (TXD) signal to the receive (RXD) signal pins 2&amp;3 on the serial port connector. Or pins 10&amp;3 on the JD SF Receiver connector. Or Pins 5&amp;6 on the iGrade connector.</span></span>

![](https://docs.t3rra.com/uploads/images/gallery/2025-03/scaled-1680-/cx7ks7qdquswu4490c-zsyvz-jeeniqp5a-png.png)

![](https://docs.t3rra.com/uploads/images/gallery/2025-03/scaled-1680-/snq4ppdidkrwzqiqcnmdigazllcdnb0hcw-png.png)![](https://docs.t3rra.com/uploads/images/gallery/2025-03/scaled-1680-/ddlldzhvavkt5hycwux-nsgsvjs08lygbg-png.png)

<span style="font-family: Helvetica,sans-serif;">  
</span>

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">While these pins are connected, press the </span><span style="font-size: 14pt;">**Open Port**</span><span style="font-size: 14pt; font-weight: 300;"> button.</span></span>

<span style="font-family: Helvetica,sans-serif;">  
</span>

<span style="font-family: Helvetica,sans-serif;"><span style="font-size: 14pt; font-weight: 300;">The serial port raw data should populate the messages as indicated below, this would indicate both the send and receive pins are working correctly and the harnessing is connected correctly.</span></span>

![](https://docs.t3rra.com/uploads/images/gallery/2025-03/scaled-1680-/jgie5btsuy15gkrr5wiivkhowzzgnzjuuq-png.png)