PoE stands for Power Over Ethernet – a method for transmitting data AND power over a single Ethernet cable.
WARNING: Before we go ANY further, If you do things wrong with PoE you can potentially damage your devices, or worse. Any of these solutions could do damage. Do your own research.
What is PoE?
Like I said – PoE is a method for delivering power to a device over an Ethernet data cable to also power that remote device.
It turns out that in a standard Ethernet cable (Cat5e, Cat6, Cat6a. Cat7 and Cat8 and above) consisting of four pairs of twisted copper wire, there are two pairs used for data and two are free and are safe to carry power.
PoE is used frequently when you need to power low power/voltage devices (usually up to 48V) over standard Ethernet cable. In offices, you’ll see it commonly used for powering IP telephone handsets, wifi access points and IP security cameras. Increasingly, it’s been used at home for the latter examples, too.
Typically, PoE is delivered by a router or switch which natively supports PoE. You can plug a supported device into one of the PoE enabled Ethernet ports on the PoE switch and provide your device with both power and data. Other methods involve injecting power using injectors or splitters. We’ll cover these, too.
Do you need it? Hmm. You might. But you may not, too. It’s worth knowing about though – especially while you are planning – in case it helps with some of the logistics.
Why might Helium miners want to consider this?
PoE could prove super useful for when you want to place your Helium hotspot as close as possible to an externally mounted antenna.
This might be desirable when you want to reduce the coaxial cable length to the absolute minimum to reduce signal loss between the antenna and the hotspot. Rather than mounting the antenna on the roof and locating the hotspot indoors, instead you might install the hotspot in a weatherproof container on the same pole as the antenna and have a very short run of coax to the antenna.
To do this though, you’ll need to somehow get power from inside your home, and up the pole to the hotspot. We’ll use an Ethernet cable for that.
Does my Helium hotspot support PoE?
Fortunately, some Helium hotspots natively support PoE – this means that the hotspot itself has circuitry that will accept an Ethernet cable delivering both power and data, and can use that power source to power itself.
Note: You cannot tell whether it supports PoE simply by looking the Ethernet jack! PoE is an important selling feature for these devices, and so check the technical specs for the router and see if PoE is mentioned.
Do your own research (I won’t be held responsible for you blowing up your precious hotspot!) but it appears that some hotspots from support PoE – some like the Heltec Indoor Miner do not.
What if my router or switch doesn’t support PoE?
Do not fear. There are other methods for injecting power into an Ethernet cable. Standalone injectors can be had, which takes a plain old data-only cable from a switch as an input and outputs the same data cable, but now with the power added in. From here you can plug in your PoE supported device and provide it with the power it needs.
These PoE injectors tend to run $20-50 but YOU MUST CHECK the output voltages they deliver – some deliver far too much 48v for a hotspot (most hotspots seem to 5v or 12v) and you will undoubtedly blow it up!
Yeah, but what if my Helium hotspot doesn’t support PoE?
There’s an option for that too, and this is actually probably the cheapest alternative and possibly the most flexible option, too.
It takes the non-PoE devices you have and injects power into the ethernet cable between them, then at the other end, splits out the data and power again so you can use them with your non-PoE device. Sounds like magic, doesn’t it?
There are these special Passive PoE splitter/injector cables/adaptors you can purchase which take a data-only cable as an input ALONG with the power output from a standard power brick (like the one that comes with the hotspot).
These TWO INPUTS combine into a jack that another ethernet cable plugs into. This cable can be quite long, and now carries the power AND data, and you run this cable to where your hotspot is located*.
* Make sure you use Ethernet cable that is rated suitable for running outdoors and being exposed to the weather!
Before it reaches the hotspot though, you plug it into another splitter. This time it takes the one input (running the combined power and data) and separates it into a data only Ethernet cable which you plug into your hotspot, AND a power jack supplying the power to your hotspot. Plug this one into the power input on the hotspot, et voila – you have powered your device over a long ethernet cable AND neither your Helium hotspot nor your switch/router need to support it!
These splitters come in pairs and have the appropriate male/female ends to complete this approach. By now you may be confused.
Here’s a simple and very crude diagram:
I literally drew this in MS PowerPoint.
These passive splitter/injector devices are VERY cheap – usually less than 15 bucks a pair on eBay or Aliexpress, but be careful for quality and read the reviews to see whether they are going to be good enough for your application.
Be careful too, that these passive splitter solutions provide no regulation of the input voltage. If you have the wrong thing plugged in at one end, you could toast your device at the other.
There you go – a bit of a PoE 101, and how the various options work. I hope this helps with understanding and that this info helps with your Helium Hotspot planning and deployment!
As usual, leave a comment below if you have something to add to the conversation. Cheers!
