# ComNav T300 / K8

The ComNav (SinoGNSS) T300 and K8 are GNSS receivers by ComNav Technology. The T300 is a widely used professional survey receiver with a built-in 4G modem, UHF radio option, and multi-constellation tracking. The K8 is a compact, cost-effective receiver sharing the same NTRIP workflow. Both receivers are configured through **ComNav Survey Master** field software running on an Android controller.

## Requirements

* **ComNav T300 or K8** powered on with clear sky visibility
* **Survey Master** field software on an Android controller or tablet
* **Internet connection** via the receiver's internal 4G modem (SIM card), phone hotspot, or controller mobile data
* **RTKdata.com account** with active RTK credentials (username starting with `rtk` and password from your RTK dashboard)
* **Survey pole** with ComNav adapter

{% hint style="info" %}
Don't have an RTKdata.com account yet? [Start 30-day Free Trial](https://rtkdata.com/try-rtk-corrections-free-for-30-days/) or [View Pricing](https://rtkdata.com/pricing/)
{% endhint %}

## Step-by-step setup via Survey Master

{% stepper %}
{% step %}

#### Connect to the receiver

1. Power on your T300 or K8 receiver and wait for satellite tracking to begin.
2. Open **Survey Master** on your Android controller.
3. Turn on Bluetooth on the controller.
4. Go to **Device** > **Connect** and tap **Find Device**.
5. Select the serial number of your ComNav receiver from the Bluetooth device list.
6. Allow pairing. Survey Master will display the receiver information once connected.
   {% endstep %}

{% step %}

#### Set the work mode to NTRIP Rover

1. In Survey Master, go to **Device** > **Work Config** (or **Work Mode**).
2. Set **Work Mode** to **Rover**.
3. Set **Data Link** to one of the following:
   * **Rover NTRIP** (or **Internal NTRIP Client**) — uses the receiver's built-in 4G modem with a SIM card inserted.
   * **PDA CORS** — uses the Android controller's internet connection (phone hotspot or mobile data). This is useful if the receiver does not have a SIM card.

{% hint style="info" %}
If using **Internal NTRIP Client** (receiver modem), you will need to configure the **APN** for your mobile carrier. Common APNs are pre-stored; select yours or enter it manually.
{% endhint %}
{% endstep %}

{% step %}

#### Enter RTKdata.com NTRIP settings

Fill in the NTRIP connection fields. Select the tab for your region:

{% tabs %}
{% tab title="North America" %}

* **IP / DNS Address:** `rtk.rtkdata.com`
* **IP fallback:** `13.56.117.10`
* **Port:** `2101`
* **Username / Password:** From *RTK Credentials* in the internal dashboard (not website login)
* **Mountpoint / Source:** `AUTO`
  {% endtab %}

{% tab title="Europe" %}

* **IP / DNS Address:** `eu.rtkdata.com`
* **IP fallback:** `3.73.41.96`
* **Port:** `2101`
* **Username / Password:** From *RTK Credentials* in the internal dashboard (not website login)
* **Mountpoint / Source:** `AUTO`
  {% endtab %}

{% tab title="Australia" %}

* **IP / DNS Address:** `aus.rtkdata.com`
* **IP fallback:** `54.206.56.130`
* **Port:** `2101`
* **Username / Password:** From *RTK Credentials* in the internal dashboard (not website login)
* **Mountpoint / Source:** `AUTO`
  {% endtab %}
  {% endtabs %}

{% hint style="warning" %}
Type `AUTO` manually in all capital letters. You can also tap **Source List** to browse available mountpoints, but typing `AUTO` directly is faster and avoids source table timeouts.
{% endhint %}
{% endstep %}

{% step %}

#### Verify GGA position sending

Survey Master automatically sends GGA position data to the NTRIP caster as part of the standard NTRIP handshake. Verify that:

1. GGA sending is not explicitly disabled in the NTRIP settings.
2. The receiver has at least a standalone satellite fix before the NTRIP connection starts.

{% hint style="danger" %}
RTKdata requires GGA position data to select the nearest base station. Without GGA, the connection will succeed but no corrections will be delivered.
{% endhint %}
{% endstep %}

{% step %}

#### Apply and start the survey

1. Tap **Enter** or **Apply** to save the work mode configuration.
2. Survey Master will connect to the NTRIP caster and begin receiving corrections.
3. You can verify the connection status under **Device Info** > **Status**.
4. Watch the solution status: **Single** > **Float** > **Fixed**.
5. Once Fixed, you are ready to collect points, stake out, or run your survey workflow.
   {% endstep %}
   {% endstepper %}

## Alternative: Setup via ComNav Web UI

ComNav T300 receivers with built-in Wi-Fi also expose a web-based configuration interface:

1. Connect your phone or laptop to the receiver's Wi-Fi hotspot.
2. Open a browser and navigate to the receiver's IP address (check the receiver manual for the default address).
3. Navigate to the RTK work mode settings and enter the NTRIP parameters as listed above.
4. Apply the configuration.

## Known quirk: RTK quality setting

{% hint style="warning" %}
ComNav receivers have an **RTK Quality** parameter that defaults to **Quick** on some firmware versions. This mode can produce false Fix solutions under marginal conditions. If you notice unreliable Fix positions, change the RTK Quality setting from **Quick** to **Normal** in the receiver's advanced settings. This forces stricter ambiguity resolution and more reliable solutions.
{% endhint %}

## Compatible field software

In addition to Survey Master, ComNav receivers are compatible with:

* **CGSurvey** — ComNav's alternative field software (PDA CORS mode available)
* **Carlson SurvPC / SurvCE** — configure NTRIP under Equip > GPS Rover > Internet settings
* **MicroSurvey FieldGenius** — configure NTRIP under Instrument > GNSS Rover Setup
* **SW Maps** — free Android GIS/survey app with built-in NTRIP client

## Vertical reference (heights)

{% hint style="info" %}
Heights from RTKdata.com are **ellipsoidal**, not orthometric (mean sea level). Configure a geoid model in Survey Master under your project coordinate system settings if your project requires orthometric heights.
{% endhint %}

## Troubleshooting

| Problem                                 | Cause                                          | Fix                                                                                                      |
| --------------------------------------- | ---------------------------------------------- | -------------------------------------------------------------------------------------------------------- |
| No internet connection (Internal NTRIP) | SIM card or APN issue                          | Verify the SIM card has data. Configure the correct APN for your carrier.                                |
| No internet connection (PDA CORS)       | Controller has no data                         | Verify your Android device has mobile data or Wi-Fi.                                                     |
| Mountpoint not found                    | Typo or wrong case                             | Type `AUTO` in ALL CAPS. Do not include spaces.                                                          |
| No corrections received                 | GGA not being sent                             | Ensure the receiver has at least a standalone fix. Restart the rover connection.                         |
| False Fix / unreliable positions        | RTK Quality set to Quick                       | Change RTK Quality from **Quick** to **Normal** in advanced receiver settings.                           |
| Stuck on Float                          | Poor sky conditions or far from base           | Move to open sky. Check RTKdata base coverage at [rtkdata.com](https://rtkdata.com).                     |
| Credentials rejected                    | Using website login instead of RTK credentials | Use the username (starting with `rtk`) and password from your RTK dashboard, not your website account.   |
| Bluetooth pairing fails                 | Device not discoverable                        | Restart the receiver. Ensure Bluetooth is enabled on both devices. Use **Find Device** in Survey Master. |

## Tips and tricks

* **The T300's built-in 4G modem** provides reliable internet without needing a phone hotspot — insert a SIM card and select Internal NTRIP Client mode.
* **PDA CORS mode** is the quickest way to get started if you do not have a SIM card for the receiver — it routes internet through the controller.
* **Save the work configuration** so your crew can reuse it across projects without reconfiguring.
* **Check correction age** in the Survey Master status display. Values above 5 seconds indicate an unstable internet link.
* **ComNav receivers support RTCM 3.2** including MSM5 messages — this is the format RTKdata delivers.
* **Keep firmware updated** via the ComNav firmware update utility to benefit from the latest RTK engine improvements.
* **For the K8**, pair with a rugged Android phone running Survey Master for a lightweight, cost-effective RTK solution.