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T-Mobile 5G Internet Gateway (Arcadyan TMO-G4AR) External Antenna Guide


Looking to get the best possible data rates from your T-Mobile 5G Internet Gateway?

T-Mobile has finally added official support for external antennas! So you’ll want to purchase and connect external MIMO antennas to the device’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

Note: The Arcadyan TMO-G4AR T-Mobile Home Internet Gateway is expected to launch officially in mid of September, per a reliable source.

Rejoice! T-Mobile Has Made Installing External Antennas Easy!

Great news! T-Mobile has listened and made adding external antennas a breeze on their new 5G Gateway. No more disassembly struggles like before.

Our community's determination showed T-Mobile how much we crave faster speeds. They heard us loud and clear, bringing us the antenna support we wanted for the T-Mobile 5G Home Internet Gateways, with four SMA-Female Ports.

We're working through some testing, and we will update this guide with more detailed port recommendations when we have them.

And, in case you're wondering, yes! Our antennas are perfectly compatible with this new gateway by T-Mobile, if you're looking for the highest gain and fastest speeds.

The Best External Antennas for the T-Mobile 5G Internet Gateway

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

This T-Mobile 5G Internet Gateway has four cellular SMA ports on the back. These allow for a 4x4 MIMO antenna array to be connected to the device.

Which of the two different MIMO External Antenna kit options to use depends on whether or not you have line-of-sight to the tower.

For most users the best external antenna choice for the T-Mobile 5G Internet Gateway is our 4x4 MIMO Panel Antenna kit. This antenna doesn’t require line-of-sight to the tower.

Best For Most Users

This MIMO panel antenna kit will provide meaningful signal improvement, even if you're surrounded by trees, hills, or tall buildings.

However, if you have line of sight to the nearest tower, we recommend using a 4x4 MIMO Log Periodic Antenna kit instead. The higher gain on these antennas can get you better performance, but only when you have a straight shot to the tower.

Best With Line Of Sight

These cross polarized log periodic antennas are have higher gain and are more directional, but work best if you have direct line-of-sight to the tower.

Why External Antennas Are Critical for Improving Data Rates

There's one big misconception about external antennas.

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 actually probably the third most important way 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

Routers like the T-Mobile 5G Internet Gateway support an LTE feature called "carrier aggregation."

Carrier aggregation allows the T-Mobile Gateway to connect on multiple cellular bands simultaneously.

The more bands you're connected to, the greater the bandwidth, and the higher your data rates.

However, many of the higher frequency bands aren't able to penetrate into buildings. Using external antennas allows you to access higher frequency bands, which are often less congested and offer higher speeds than lower frequency bands.

3.They Increase Your Signal Strength

As you might expect, using outdoor directional antennas can help increase the signal strength.

This helps increase data rates, but only up to a point.

If your signal strength (called "RSRP" in LTE networks) is stronger than about -100 dBm, stronger signal won't speed up your connection any further.

Installing External Antennas to the T-Mobile 5G Internet Gateway

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: 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 5G Internet Gateway

Location of the SMA ports on the T-Mobile 5G Internet Gateway

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 you'll criss-cross ports 2 and 3 by connecting port 2 to "ANT 3" and port 3 to "ANT 2". We know that this sounds odd, but criss-crossing these connections seems to provide a boost in performance!

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: To make connecting your cables easier, we recommend obtaining four 90 Degree (Right Angle) SMA-Male to SMA-Female Adapters. While we don't currently offer such an adapter through our store, there are many options online.

STEP 3: 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 might restart, but it will now be using the external antennas to pull in the best signal.

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 4x4 MIMO instruction manual to accompany our own 4x4 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: 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.

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!

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 helping us improve this guide!