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A 4G router in my aircraft?

Updated: Jan 13

The weather finally improved, allowing us to continue the tests we mentioned back in December 2022.

FJFVB at EBBY parking

Objective of the test:

Install a 4G router with an external antenna to conduct internet reception tests during flight.

Read on to find out more, and rest assured, we'll keep it simple!

The idea

The idea behind this was simple. SafeSky's forum fosters exchanges, ideas, and trials among its members. One of our pilot-users proposed testing the installation of a 4G router with an antenna to verify mobile internet reception improvements during flight. We were encouraged by his positive feedback and decided to try it out ourselves and share our findings with the community.

Material and installation

We only needed two pieces of equipment: a 4G router with antenna output(s) and an antenna.

NetGear M2 Router

Personally, I had a NetGear Nighthawk M2 router, and Amazon took care of the selection of a compatible 4G antenna with an SMA connector. Admittedly, the price of the NetGear router is excessive considering its intended purpose, but if you already own one that you use on vacation, for example, don't hesitate to use it.

As for the antennas, I chose to test a simple, flat, and aerodynamic model (+/- €12) and another model with two connection cables (+/- €17). The antennas were affixed to a vinyl wrap adhesive to avoid attaching them directly to the aircraft's paint. The cables travel from the landing gear to the cabin, passing through the seats. It was easy and temporary, just what I needed.

Time to test it out on a flight from EBBY to LFAY!

The weather is good, so we should take advantage of it! We're taking two planes to run SafeSky under different configurations, including on a phone, a tablet, and of course, the famous router + antenna.

My fellow pilots Claude and Jean-Pierre are preparing their MCR01 while I install the last connections and settings onboard my VL3.

It's hard to stir the propeller in the morning!

My setup is straightforward. I regularly use my 11" iPad Pro on a dedicated mount on the right-hand side. Typically, it's equipped with a SIM card but today I transfer it to the router for testing purposes. SafeSky will be displayed on the iPad in Splitview 1/3 - 2/3 with my navigation software. I love this configuration because it leaves enough space for my navigation while offering an ideal area for SafeSky's radar. By sharing traffic with the navigation software, I can also visualise it perfectly in my environment thanks to the aeronautical maps. For me, it's the epitome of efficiency and, above all, safety.

iPad in SplitView set-up, alert received in full vertical Albert Bray (LFAQ)

Testing protocol

The distance between Baisy-Thy airport (EBBY) and Amiens airport (LFAY) is 96 NM, and the flight should take approximately 50 minutes. The areas we'll be passing through are known for signal losses due to the presence of white zones (areas without coverage), as well as roaming between Belgium and France when crossing the border.

Therefore, I decide to connect my tablet to my phone's wifi during the outbound flight, taking advantage of the shared connection since my SIM card is in the router. On the return flight, I will connect the tablet to the 4G router's wifi network, making use of the external antenna. I have also installed two cameras, which allows me to create a short video to illustrate the flight:

Everything is in place, runway 05 in use, wind from 070 at 15 knots, CAVOK. The sky is all ours.

FJVZJ is lining up on runway 05 for immediate takeoff and I will follow shortly with FJFVB.

The return flight

Let's talk about the flight. As a reminder, the outbound leg to Amiens will be conducted using only the phone, without any external antenna. For the return, we will take exactly the same route and altitude (2000' QNH) to see if there are any differences.

During the outbound flight, we experienced some internet connectivity issues in well-known zones near Charleroi and Mons. These are the so-called "white zones" that we have identified since the beginning of our testing with our application over two years ago. This makes it the perfect location to check for any potential differences.

The map below outlines the flight path and the internet connectivity evolution.

From EBBY to LFAY. Overall a good network coverage with a basic phone configuration.

Several elements to note and explain about this flight:

  • Zone A: Known dead spots between Mons and Charleroi. As expected, the phone loses its signal but quickly regains it.

  • Zone B: Near Valenciennes, the Belgium-France roaming takes place. The loss of signal is normal as it switches to the French network. Additionally, we had already noted dead spots near the Valenciennes aerodrome, so this situation is expected.

  • Zone C: A brief loss (37 seconds) occurred above the A2-A26 highway interchange.

Apart from the roaming issue (zone B), which is a technical reality between countries, we can consider this to be a very steady flight path. It's worth noting that during this flight, air traffic control reported another aircraft (between A and B). It was a helicopter flying 100 feet lower, and although it wasn't equipped with SafeSky, it did have an ADS-B out transponder, which I was therefore able to see on my SafeSky screen and then locate outside quickly. This highlights the importance of having a software that can represent the majority of location systems (ADS-B, Flarm, and many others). SafeSky is doing that, acting like a translator that enables everyone to see each other even if they don't speak the same language.

Let's now take a look at the return flight path with the tablet connected to the router's hotspot, equipped with the external antenna:

From LFAY to EBBY. A continuous network coverage line, thanks to the external antenna.

Visually, the difference is striking. The trace is continuous, a clear proof of near-perfect internet reception. But what happened near the EBBY airfield during our arrival? We think that the antenna worked so well that roaming did not occur shortly after crossing the border, but instead occurred near EBBY well inland. This is surprising but not illogical.

We could not resist digging deeper into the numbers, and here is what we found:

We considered only the data when the plane was AIRBORNE. We went from 83% internet connection with the phone to 88% with the router and antenna. This difference of 5% is not huge and does not seem to reflect the experience we had during the tests and the trace on the maps.

Therefore, we decided to conduct a new assessment without the impact of roaming and border crossing to be closer to reality. Here are the data from the same flight, but reduced between the border crossing to the west of Valenciennes and the Feluy refinery in Belgium. This area is interesting because it includes the aforementioned white zones.

These are more representative figures of our coverage perception during the flight. Please note that the difference in transmitted positions corresponds to the number of seconds without connection, as we transmit one position per second. With the router and antenna, we lost connection for 25 seconds of flight, which gives a coverage ratio of 97% at 2000', which is close to excellence. The phone in the cockpit lost its connection for 22% of the flight, but when passing through known white zones. Not so bad, you will admit.


As a reminder, our tests are intentionally simplified, and are far from being scientific. We wanted to have a first perception of the advantage brought by the placement of an external antenna. The result, even though it was expected, confirms all the good that can be thought of such an installation.

To our knowledge, it is not currently possible to connect an external antenna directly to a phone or tablet. The option of a router with the possibility of connecting an antenna is the only viable solution. Can a router without an antenna improve reception? I don't think so, but it can make your connectivity on board easier.

Soon, we plan to conduct additional tests following the protocol outlined below:

  1. We will use a phone with SafeSky and a connected tablet on a router, both on the same plane, in order to compare identical data under perfectly similar flight conditions.

  2. We will fly on a predetermined route at different altitudes (1500', 2500', 3500', 5000') to evaluate the signal's reliability at various heights.

The NetGear M2 router used for this test is quite expensive (approximately €420), but it offers the advantage of two connections for an external antenna. If you already use this router for your family's camper van for instance, then the investment is worthwhile; otherwise, the cost may be unreasonable. However, there are other products available (such as Huawei) at lower costs that will work just as well, provided that you ensure the possibility of connecting an external antenna. For tech-savvy and computer enthusiasts, there are many other solutions available, but they require knowledge of electronics, telecommunications, and computing. Please do not hesitate to share your ideas with us at

We need your help!

Do you want to help us evaluate similar solutions? Maybe you have already conducted yourself such tests or are inspired to do so after reading this article? Please get in touch with us at .

Safe flights.

Christophe ERKENS

Co-Founder SafeSky


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