Coaxifi Wi-Fi over coax review

Coaxifi turns your home cable wiring into a Wi-Fi antenna, but it's not simple

Coaxifi boosts performance, but not as much as promised, and its installation is seriously tough.
Coaxifi boosts performance, but not as much as promised, and its installation is seriously tough.
Coaxifi boosts performance, but not as much as promised, and its installation is seriously tough.

Highs

  • Improves Wi-Fi coverage
  • Compatible with internet-over-cable

Lows

  • Requires external antenna-equipped router
  • Potentially complex install
  • Only modest performance increases

DT Editors' Rating

As we populate our homes with more and more wireless devices, the quest for better Wi-Fi coverage has become something of an obsession, leading to a slew of new Wi-Fi products. Some of these use mesh technology, placing several Wi-Fi nodes around your home, while others take a brute-force approach, placing up to eight antennas on a single, powerful router. Still others make use of portions of the Wi-Fi spectrum typically reserved for military and commercial radar known as DFS. To take advantage of these new products — which do indeed improve WI-Fi for most people — you’ll have to ditch your existing router and invest a minimum of $260 – possibly, much more. That’s why we were curious to try out a new Kickstarter-funded solution from a company called EthernetCSP in our Coaxifi review.

Coaxifi is an antenna extender and splitter which lets you connect your home’s existing coaxial cable to one of your router’s antenna ports, significantly improving Wi-Fi coverage by placing additional antennas in up to four locations around your house. Better still, pricing starts at $90 for Kickstarter backers ($130 at retail) – a lot less than a mesh router system. Does it work? 

What is it, exactly?

The Coaxifi kit is a custom built four-way splitter — which is the heart of the system — four multi-band antennas, and six SMA-to-Type-F adapters, which let you connect everything to the router. The company also throws in a cable tester. This is all you need to turn your unused coax cabling into a network extender for a router.

However, if you still use your coax cable for TV and for internet access, things get a lot more complicated. That’s because you’re essentially using cable for three different signals (TV, internet, and Wi-Fi), and there’s a great deal of combining and separating of these signals that needs to be done in order for it all to work. It’s still possible, but neither we nor EthernetCSP recommend it.

Tricky installation

Coaxifi is, on the surface, simple to install alongside a Wi-Fi router with at least one external antenna, but it’s nowhere as easy as plugging in a new router. Depending on your home and comfort with messing around with cabling, it could take as little as 30 minutes, to over an hour.

Our test house was wired recently, so cable quality was not a factor, but not everyone will be so lucky.

Installation involves removing one of your router’s antennas and connecting the closest available coax cable to that port using an included SMA-to-Type-F adapter (coaxial cable and router antennas both use screw-on connections, but they’re different sizes). You then need to find the point in your home where this cable is joined to the other cables by a splitter. That could be in the basement, in a closet, or even outside the home; for us, it was on an outside wall. The Coaxifi splitter itself is very small, and weather-proof, but it does not come with the rubber seals needed to protect the five adapters from the elements.

In our case, we had to open up a junction box owned by the cable company to gain access to the end of our chosen cable. That’s a legal grey area, because some cable companies are defensive about tampering with such equipment, even if it’s on your property.

Then, there’s the question of cable type. Coaxifi is designed to work with RG6 coaxial — a thick, well-shielded type of coax used in most homes built in the last 30 years. But older homes often have older cables, and these cables may not be able to reliably pass Wi-Fi frequencies. Our test house was wired recently, so cable quality was not a factor, but not everyone will be so lucky.

Lastly, the kit’s antennas must be attached to cable outlets around your house, which are now connected to the Coaxifi splitter. This is the easiest step by far.

Why would you want Coaxifi?

You may be wondering why you need Coaxifi’s splitter at all. If you’ve already got a splitter on your cables, why not just re-wire the inputs and outputs to connect it up the right way for the antennas?

The answer has to do with frequency. Traditional cable splitters are designed to split TV signals – which typically operate at anywhere from 0 – 1,000 MHz. Coaxifi is a four-way splitter specifically designed to split the Wi-Fi signals picked up by your router’s antennas, which are a much higher frequency — anywhere from 2.4 to 5.8 GHz — a traditional splitter wouldn’t be able to pass them correctly.

As strange as it sounds, modern coaxial cable is an excellent conduit for Wi-Fi. Wi-Fi, much like any other type of radio wave, starts off life as an electrical signal before it gets transmitted through the air via the antenna. In fact, inside your router, a much shorter cable is already doing exactly that. Using your home’s coaxial cable to extend the distance of a Wi-Fi router’s antenna is no different than using an electrical extension cord to move an appliance like a TV further away from a wall plug.

The challenge with extending Wi-Fi in this way is attenuation. Attenuation is the drop in power, or signal strength, that naturally happens any time you pass a current through a medium, whether that medium is air — which is what happens to Wi-Fi signals when they leave your router’s antennas — or copper wire inside a coaxial cable. There’s far less attenuation when you go through a cable than when you go through the air, but there’s still some that happens. In order for Coaxifi to live up to its promise, there must be less overall attenuation of Wi-Fi signal between the router and your wireless gadgets than if you had never hooked it up in the first place.

Does it work?

Yes and no. When connected to the Coaxifi system, our test router delivered a 20 percent average improvement in throughput when using the 5GHz band, throughout the whole house. However, the router performed 30 percent better on average when using the 2.4GHz band using just its own antennas. Also, using Coaxifi had a negative impact on speeds at close ranges to the router.

Average numbers only tell some of the story, however. In the two locations where Wi-Fi typically struggles the most in our test house (Locations D and F) the test router performed noticeably better when connected to Coaxifi, on both bands, and in the basement (Location F), it delivered an astonishing 400 percent improvement when using the 2.4GHz band.

We could have stopped there and declared the Coaxifi a bona fide success — after all, 400 percent is impressive — but the Coaxifi Kickstarter page makes some pretty bold claims.

“It goes through walls, sheet metal, and all the other obstructions in your home that ordinarily deflect Wi-Fi signals.”

“With 2-4 layers of aluminum shielding on each cable to block interference, and a signaling speed of 650 feet per millisecond, coaxial cable is the perfect medium for Wi-Fi. Whereas signal loss can make regular Wi-Fi unsuitable for real-time applications at just 25 feet from the router, Wi-Fi over Coax gives you coverage at any distance from the router even in a 5,000 square-foot house. And unlike Wi-Fi-over-Wi-Fi meshes, Wi-Fi over Coax does not increase your ping time or cut your bandwidth with a mess of unnecessary access points. The best part? It goes through walls, sheet metal, and all the other obstructions in your home that ordinarily deflect Wi-Fi signals.”

With language like that, our expectation was that we’d enjoy Wi-Fi that was as fast in each location that had a coax-extended antenna as it was in the location with the router itself, or at least a significant fraction thereof. In that regard, Coaxifi left us underwhelmed. We still experienced the same relative drops in both signal strength and throughput as we moved further away from the router, with or without Coaxifi. It simply preserved more performance. It was definitely not like using a device “where the signal strength is strongest.”

How did we test?

We used the most comprehensive test available to us to verify it, because the bigger the claim, the more thorough the test should be. Our test router was a Linksys WRT1900 ACS, with four external antennas. For each test, we ran the router with all four factory antennas attached, and in optimal orientation for our test house. Then we ran them again with the left-side antenna removed, and in its place, we attached our coax cable, using the Coaxifi splitter, with Coaxifi’s four antennas installed throughout the house.

coaxifi house diagram

We ran an iPerf3 server on a late-2012 iMac, wired into one of the router’s gigabit Ethernet ports, and used a Google Pixel XL as the iPerf3 client. For each tested location, we sent 1MB of data a total of 10 times, and averaged the throughput. We also took measurements of signal strength for each band.

The Details

2.4GHz Throughput Test in Mbit/s | Source: iPerf3 (iMac Server, Pixel XL Client)

Location 4 Coaxifi Antennas connected to Linksys WRT1900ACS (Location C) Linksys WRT1900ACS
(Location C)
A 8.308 14.063
B 22.09 25.649
C 30.071 43.47
D 17.723 11.93
E 17.041 29.21
F 10.49 2.121

5GHz Throughput Test in Mbit/s | Source: iPerf3 (iMac Server, Pixel XL Client)

Location 4 Coaxifi Antennas connected to Linksys WRT1900ACS (Location C) Linksys WRT1900ACS
(Location C)
2x Portal Router, Mesh Configuration at Locations C & D
A 51.44 31.856 81.24
B 69.13 53.213 86.06
C 103.61 99.85 105.48
D 37.42 37.15 63.09
E 85.29 71.59 93.66
F 15.03 12.509 52.69

Better than mesh?

Another of Coaxifi’s claims is that it’s better to have multiple antennas throughout a house, connected via coax cable to a single router, than it is to use mesh networking, which according to the campaign page “ping-pongs” the signals between multiple access points. To test this claim, we re-ran our throughput test using two Portal routers configured as mesh access points. As you can see in Table 2, it was no contest. The meshed Portals provided consistently faster speeds over the 5GHz channel. We did not test this over the 2.4GHz, because we believe that’d defeat the point of a dual-router mesh arrangement. 5GHz is faster, but suffers shorter range.

Warranty information

Coaxifi comes with a 30-day money-back guarantee and a one-year manufacturer’s warranty.

Our Take

It’s easy to admire the sheer cleverness of a system that extends Wi-Fi coverage using little more than a house’s own coaxial cabling. Yet despite its low cost, Coaxifi doesn’t give a big enough boost in performance to justify its tricky installation. Its dependency on a router that has external antenna ports, and the additional complexity of trying to work with internet-over-cable or TV-over-cable, further reduces the number of people who will find it an attractive option.

That said, if you’re a die-hard DIY tinkerer who can’t stand the idea of throwing money at a problem, Coaxifi offers an alternative to buying a new router.  

Is there a better alternative?

While Coaxifi’s approach is unique, there’s no shortage of competitors that use different tricks. The industry’s current favorite approach, mesh networking, works very well, but can get expensive quickly when you start adding nodes. Google Wifi is a good place to start. We also like the Securfi Almond 3, which is more expensive, but has a touchscreen for changing settings and supports some home automation features.

It’s also worth exploring powerline networking products which use your home’s electrical system as an extension of your router’s Ethernet ports, letting you stick a secondary Wi-Fi access point almost anywhere in your house, for less than the price of second router. If you have an older router still kicking around, you may be able to wire it to your main router via Ethernet too, giving you a cheap and easy network extension. Finally, there are wireless range extenders, which we generally don’t recommend as they tend to cut bandwidth in half.

How long will it last?

Thanks to its simplicity, and lack of any powered electronics, the Coaxifi should last years, possibly even decades. As long as your router possesses at least one SMA external antenna port, Coaxifi should continue to work.

Should you buy it?

For the average consumer who simply wants better Wi-Fi coverage, with the least amount of hassle, Coaxifi is not a good option. We like that once installed it’s virtually maintenance-free for the life of your home, however, the installation itself isn’t as painless as the campaign page suggests, and the increase in performance isn’t as dramatic as promised.

For about $270 (about $180 more than a Coaxifi), you can buy a pair of meshed Portal routers, or a three-pack of Google Wifi routers, both of which will give you much better speed and coverage, not to mention the latest Wi-Fi technologies, standards, and security, over an older router.