---
updatedAt: 2025-11-12T23:36:15.000Z
agentTools:
  projectIndex: https://docs.sixfab.com/llms.txt
---

# Technical Details

This section introduces the concepts and terms that are crucial for the understanding, implementation and use of Sixfab 5G Modem Kit

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# 5G Modem Carrier HAT

The detailed specifications of the Raspberry Pi 5G HAT are provided below.

## Pinout

![Pinout image alt][pinout]

## Pin Descriptions

<Table align={["center","center","center",null]}>
  <thead>
    <tr>
      <th>
        Pin Number
      </th>

      <th>
        BCM Pin
      </th>

      <th>
        Pin Name
      </th>

      <th>
        Description
      </th>
    </tr>
  </thead>

  <tbody>
    <tr>
      <td>
        33
      </td>

      <td>
        GPIO13
      </td>

      <td>
        SIM Select
      </td>

      <td>
        It is used to toggle between the nano SIM card and the embedded SIM.\
        Default state is LOW selecting nano SIM. Set to HIGH for embedded SIM. It requires module reboot using FCP pin.
      </td>
    </tr>

    <tr>
      <td>
        13
      </td>

      <td>
        GPIO27
      </td>

      <td>
        Fan On/Off - PWM Control
      </td>

      <td>
        The pin turns on the FAN when set to HIGH. Default is LOW. PWM can control fan speed. In the included Raspberry Pi OS, fan is set to full speed at 60°C. At 50°C, fan turns off.
      </td>
    </tr>

    <tr>
      <td>
        37
      </td>

      <td>
        GPIO26
      </td>

      <td>
        5G Module FCP
      </td>

      <td>
        This pin controls power on/off of the module. Setting it to HIGH powers off the module after 10 seconds. Setting it to LOW initiates power-on sequence of the module and is fully functional after 50 seconds. Default state of the pin is LOW.
      </td>
    </tr>

    <tr>
      <td>
        40
      </td>

      <td>
        GPIO21
      </td>

      <td>
        User LED
      </td>

      <td>
        When the pin is pulled HIGH, the LED lights up.
      </td>
    </tr>

    <tr>
      <td>
        38
      </td>

      <td>
        GPIO20
      </td>

      <td>
        User Button
      </td>

      <td>
        This pin is pulled to the default HIGH state. When the button is pressed, the pin is pulled to the LOW.
      </td>
    </tr>

    <tr>
      <td>
        35
      </td>

      <td>
        GPIO19
      </td>

      <td>
        Power LED Off
      </td>

      <td>
        If you want to turn off the Power LED, you can set this pin to HIGH. By default, the Power LED will always be on.
      </td>
    </tr>

    <tr>
      <td>
        15
      </td>

      <td>
        GPIO22
      </td>

      <td>
        Power Disable
      </td>

      <td>
        Set the pin to HIGH to completely cut off power from the HAT, disabling power consumption. In case of module unresponsiveness, use this method to power cycle the HAT. Setting the pin to LOW supplies power to the HAT. Default state of the pin is LOW.
      </td>
    </tr>
  </tbody>
</Table>

## Layout

![Layout image alt][layout]

## LEDs

* **POWER LED:** The LED indicates power status of the HAT and can also be controlled via GPIO19. Refer to the pin descriptions table for instructions.
* **STATUS LED:** The LED indicates the RF function of the module. Turns on when RF Function is on.  Turned off when the SIM is not powered or RF function is disabled.
* **USER LED:** It is a programmable user-LED that can be controlled from the GPIO21 of Raspberry Pi for debugging or just fun.

## Buttons

* **User Button:** It is a programmable user button that is connected to GPIO20. It reads HIGH by default.

## 5G Module

The module used in 5G Modem Kit is the Quectel M.2 5G Sub-6 RM502Q-AE module.

# Frequency Bands

**5G NR SA Bands:** n41 (2469-2690MHz), n77 (3300-3800 MHz), n78 (3300-4200 MHz),n71(617-698 MHz)\
**5G NR NSA Bands:** n41

# Data Speed

**5G SA Sub-6:** Downlink 4.2 Gbps; Uplink 450 Mbps\
**5G NSA Sub-6:** Downlink 5.0 Gbps; Uplink 600/650 Mbps

# Region

Global

# Network Protocols

TCP/UDP/FTP/HTTP/HTTPS/PING/SMS

# Dimensions

88.1 x 57.7 x 21.7 mm

# Weight

The total weight of the HAT is 68.37 grams.

# Power

Sixfab recommends to use of official power adapters for the product. Use the power adapter included in the kit with the HAT. The detailed power analysis of the product will be updated here soon.

# USB Bridge

The USB Bridge serves the purpose of connecting the 5G module with the USB 3.0 port of the Raspberry Pi. This design choice was made in favor of using a USB cable, as it provides a robust, aesthetic, and space-saving solution. Rather than a standard straight cable connection, the USB Bridge has been specifically designed with filtering components to ensure faster and more efficient data transmission.

# Antenna

This antenna has been specifically designed and produced by Sixfab engineers, focusing on 5G bands and frequencies, exclusively for the 5G modem kit.

The connections between the antenna and the 5G module are established using MHF4 connectors and custom-made MHF4 cables.

For in-depth technical specifications regarding the antenna, please consult the details provided below.

The designed 5G terminal antenna is 4X MIMO Micro-strip antenna, which operates over:

**5G NR SA Bands:** n41 (2469-2690MHz), n77 (3300-3800 MHz), n78 (3300-4200 MHz),n71(617-698 MHz)\
**5G NR NSA Bands:** n41

## Return Loss

![](https://files.readme.io/8b6bbe6-image.png)

|                     |       |       |        |     |
| :------------------ | :---- | :---- | :----- | :-- |
| **Frequency (MHz)** | 2579  | 3550  | 3750   | 600 |
| **Value (dB)**      | -14.1 | -14.3 | -14.62 | -3  |

## VSWR

![](https://files.readme.io/d2070e1-image.png)

|                     |        |        |        |        |
| :------------------ | :----- | :----- | :----- | :----- |
| **Frequency (MHz)** | 2579   | 3550   | 3750   | 600    |
| **Value (dB)**      | 1.07:1 | 1.29:1 | 1.32:1 | 8.21:1 |

## Ports Isolations

![](https://files.readme.io/9a7b4be-image.png)

|                           |      |      |      |      |
| :------------------------ | :--- | :--- | :--- | :--- |
| **Frequency (MHz)**       | 2579 | 3550 | 3750 | 600  |
| **Avg. Ports Isolations** | <-20 | <-25 | <-29 | <-40 |

## Gains/Efficiencies/Polarizations

| Bands | Gains (dBi) | Efficiencies | Polarizations |
| :---- | :---------- | :----------- | :------------ |
| N41   | 3.2         | 65%          | Linear        |
| N77   | 1.99        | 77%          | Linear        |
| N78   | 2.75        | 82%          | Linear        |
| N71   | 3.03        | 78%          | Linear        |

## Propagation Patterns

<Image align="center" src="https://files.readme.io/22b1712c217a9cfa968227f832e789621b028bbf5d62c5730c74d9d440c50e9e-f6b0f17-1157364-Sixfab_Modem_Kit_5G_Antenna_Propagation_Patterns.webp" />

<Image align="center" src="https://files.readme.io/4a7506c93406835fcb4aa228d07b6af59e6b70639d22594b743c8c1108abc3e7-Sixfab_Jumpstart_5G_Propagation_Patterns.webp" />

[pinout]: https://sixfab.com/wp-content/uploads/2023/05/Sixfab-Jumpstart-5G-HAT-Pinout.jpg "Raspberry Pi M.2 HAT Pinout"

[layout]: https://sixfab.com/wp-content/uploads/2023/06/Sixfab-Jumpstart-5G-HAT-Layout.jpg "Raspberry Pi M.2 HAT Layout"

[dimension]: https://sixfab.com/wp-content/uploads/2023/05/Sixfab-5G-HAT-Dimension.jpg "Raspberry Pi M.2 HAT HAT Dimensions"