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T-Mobile 5G Internet Gateway G4AR & G4SE Antenna Guide


Looking to get the best possible data rates from your white T-Mobile Home Internet G4AR or G4SE Gateway?

This latest generation of T-Mobile gateways makes connecting external antennas a breeze. All you need is the right external MIMO antenna to connect to your gateway's four SMA ports.

In this guide, we'll:

  • Recommend the best external antennas to use.
  • Show where the SMA ports are located.
  • Explain how to aim the antennas for best results.

In this guide

Using MIMO Antennas with T-Mobile Home Internet is Now a Breeze

We're super excited that T-Mobile has listened to customer feedback and added external antenna ports to the new white G4AR and G4SE gateways.

Unlike previous generation devices like the black Sagemcom 5688W, Arcadyan KVD21, and grey Nokia 5G21, there is absolutely no disassembly required to connect MIMO antennas to these new devices.

And, in case there's any doubt: Yes! Our antennas are perfectly compatible with these new gateways from T-Mobile.

The Best External Antennas for the T-Mobile G4AR and G4SE

Using a MIMO antenna outside your building, pointed at the nearest tower, can help you get the fastest 4G and 5G data rates possible.

These new T-Mobile 5G Internet Gateways have four cellular SMA ports on the back that allow for a 4x4 MIMO antenna array to be connected to the device.

Which of the two different 4x4 MIMO External Antenna Kit options to use depends primarily on how much time you're willing to spend on aiming.

The easiest antenna choice for the T-Mobile 5G Internet Gateway is our QuadMini Antenna Kit. With up to 5.2 dBi of omnidirectional gain and multiple mounting options, it is designed to be extremely simple to install outdoors or indoors, at home or in an RV.

Easy install, no aiming

Upgrade your 5G in minutes with no aiming, and four easy mounting options.

However, if you're willing to spend a little bit of time aiming, our QuadPro Antenna Kit will generally get you the fastest data speeds, thanks to its 9.1 dBi of directional gain. This is particularly important if you're on the edge of coverage, or have very weak signal.

Best performance, requires aiming

Aim QuadPro at your nearest tower for blazing data, even at the edges of cellular coverage.

Why External Antennas Are Critical for Improving Data Rates

Most people think that external antennas primarily help you increase your data rates by increasing the signal strength. But that's not the case.

An increase in signal strength is often less important than other ways that external antennas help.

Here are the three main ways that external antennas help you increase your data rates:

1.They Improve Signal Quality

In 4G LTE and 5G networks, signal quality is measured as SINR (Signal to Interference plus Noise Ratio) or sometimes as RSRQ (Reference Signal Received Quality).

Improving signal quality has a huge impact on your data rates.

Higher data rates allow your hotspot to communicate using "higher order modulation schemes." That means they can use the same wireless spectrum to send more data per second.

However, there's one big caveat:

In order to improve your signal quality, you need to both aim and shield your outdoor antenna properly. We talk more about this in the next section.

2.They Allow You To Connect On More Bands

T-Mobile's utilizes a number of different frequency bands to deliver 5G service. Depending on your area, those bands will perform differently.

But in almost every case, T-Mobile's "n41" band, which operates in the 2500 MHz spectrum range, gets the very best download speeds. Many users are able to achieve upwards of 100 Mbps and even up to 1000 Mbps download speeds when connected to this band.

However, the n41 band is a higher frequency than other 5G bands like n5 and n71. As a result, it doesn't penetrate buildings well.

Using a MIMO antenna mounted outside your building allows your gateway to access more bands, including n41, to get the very fastest data rates possible.

3.MIMO Isolation

MIMO (Multiple Input Multiple Output) technology uses signals travelling along multiple paths simultaneously, increasing both bandwidth and reliability in wireless connections.

MIMO isolation is the antenna's ability to handle several data streams at once, cleanly and without interference, leading to quicker data speeds and steadier connections

Our external antennas are specifically designed for superior MIMO isolation, and dramatically outperform standard built-in antennas found in most home devices.

This means you'll see a more reliable connection with enhanced bandwidth, ensuring smoother streaming, gaming, and browsing with minimal interruptions.

Connecting MIMO Antennas to the T-Mobile 5G G4AR and G4SE Gateways

Before getting started, it's always a good idea to run a couple of speed tests indoors from a device connected to your T-Mobile 5G Internet Gateway's WiFi. The results will fluctuate a little, but this is the baseline you're trying to improve.

Once you've tested your baseline internet speeds, you're ready to install external antennas.

In the next section of this guide, we'll show you how to connect adapters for external antennas to your T-Mobile 5G Internet Gateway.

Step 1 - Identify The Ports

The T-Mobile 5G Internet Gateway has four cellular antenna ports that are labeled "Ant 1" through "Ant 4" and are grouped together on the back of the device. These are the ports your MIMO external antenna(s) will be connecting to.

Location of the SMA ports on the T-Mobile G4AR and G4SE Gateway

Location of the SMA external antenna ports on the T-Mobile G4AR and G4SE Gateway

Step 2- Connect Your Antenna

Step 2 Simply connect the external 4x4 MIMO antenna(s) to the SMA ports on the back of your T-Mobile 5G Internet Gateway.

You'll connect port 1 and port 4 as normal but we recommend criss-crossing ports 2 and 3 by connecting port 2 to "ANT 3" and port 3 to "ANT 2".

This may seem odd, but criss-crossing these connections seems to provide a boost in performance.

You can also try the standard 1-2-3-4 arrangement as well to see which works best in your location.

device ports
antenna ports

If you're using one of our 4x4 MIMO Antenna Kits, the cables are labeled 1 through 4 on each end to make it easier to match up connectors from your antenna to the gateway.

Tip: We have optional 90 Degree (Right Angle) SMA-Male to SMA-Female Adapters available if you'd like to make connecting/disconnecting antennas easier.

Step 3 - Change the Antenna Mode

Finally, on the built-in display of the gateway, change the antenna settings from "INTERNAL" to "EXTERNAL" to activate the external antenna ports.

Antenna settings on the TMO-G4AR

Antenna settings on the TMO-G4AR

Your Gateway will take a few moments to switch antennas. If you receive an error message at this point, read the section near the bottom of this article describing how to fix the issue.

Important Tip: Before you run a new speed test, we recommend power-cycling the gateway, or removing and then re-inserting the SIM card.

Taking this step forces the gateway to search and connect to the best bands available, and we've found it can make a big difference in performance.

Congrats! Your T-Mobile 5G Internet Gateway is now connected to your more powerful MIMO External Antennas.

Positioning and Aiming MIMO Antennas

Correctly positioning and aiming MIMO antennas is crucial to getting the best performance to your T-Mobile 5G Internet Gateway, or indeed any other router.

We've actually compiled a detailed QuadPro and QuadMini instruction manual to accompany our own MIMO Antenna Kits, where we go into depth on the best ways to aim the antennas.

The goal is to find the best location and direction for the antenna(s) to maximize data rates to the hotspot. It can take a little patience, but can have a huge impact – it’s worth a bit of extra effort!

Once you've got your external MIMO antennas connected, you're ready to go outside with your "test-rig".

With each location and direction you try, run a couple speed tests, and make a note of the results. Here are all the locations and directions where we recommend testing your MIMO antenna:

Where to test your signal

Where to test your signal

Pro Tip 1: Don’t just go to the highest point of the roof! While signal is generally stronger the higher you go, there’s also often more interference. We’ve found it’s often better to mount the antenna(s) on the side of the building where the structure can shield the antennas from interference.

Pro Tip 2: When you make bigger changes, try either power cycling or removing and re-inserting the SIM card. This forces the gateway to search for the best signal anew and can help improve data rates.

Once you've found the position which gets you the highest data rates to your T-Mobile Gateway, that's where you'll want to install the MIMO antenna. Go ahead and mount the antenna, run cables inside, connect everything up, and enjoy superior data rates!

How to Fix the "Network connectivity could not be established ... check that a supported external antenna is connected" Error Message

In testing our antennas with the G4AR and G4SE gateways, we noticed that an error like this occasionally pops up:

G4AR and G4SE external antenna error message says "Network connectivity could not be established with external antenna. Please check that a supported external antenna is connected correctly to the gateway. The internal antenna will remain active"

"Network connectivity could not be established with external antenna. Please check that a supported external antenna is connected correctly to the gateway. The internal antenna will remain active."

Note the 4G status icon in the top left of the LCD screen.

Photo credit: Brady Hourtienne

After much testing, we found the source of the issue:

This error is triggered if you have no signal or only 4G sign using the internal antennas (i.e. before you try to switch to external antennas).

Frustratingly, the G4AR and G4SE gateways will show this error message even if you have excellent 5G signal coming from your external antenna.

You can see the 4G icon in the top left of the screenshot above.

The solution is simple:

Solution: Take the gateway to somewhere where it can connect to 5G with its internal antennas (even if that means taking it outdoors or driving it to a coffee shop and plugging in there). Once you're in range of 5G, you'll be able to switch successfully.

The change to external antennas will remain in place even if you unplug the gateway from power.

T-Mobile 5G Internet Gateway Technical Specifications

Supported T-Mobile bands in the US

  • 5G: n25, n41, n48, n66, n71, n77 (DoD and C-Band)
  • 4G LTE: B2, B4, B5, B12, B25, B48, B66, B71

Cellular Modem

  • MIMO Support: 4x4 with external antennas
  • LTE-A Carrier Aggregation: Yes (2x 5G 40 MHz bands, 5x LTE 20 MHz bands)
  • LTE Performance Category: Cat 20
  • Max Theoretical Speeds: 2.5 Gbps Download, 316 Mbps Upload


  • Wi-fi Version: Wifi 6
  • Wifi Standards: 802.11ax
  • Bands: Simultaneous Dual-Band (2.4GHz / 5GHz)


  • Cellular Antenna Ports: 4x SMA-Female
  • Ethernet (RJ-45) Ports: 2x GbE RJ-45 LAN ports
  • SIM Ports: 1x 2FF SIM slot
  • Other: 1x USB-C (Power), 1x USB-C (LAN/Data)

Other Helpful Resources

Thank you NaterTater and Brady Hourtienne for helping us improve this guide!