I plan on moving my setup to a weatherproof box on the roof and my dilemma is powering it. I could keep the Pi in the attic and run coax to the antenna or put everything in a box near the antenna, the coax run would probably be 25 feet of lmr400 uf. Since the Pi is using WiFi I don’t need Ethernet so I was wondering how to go about using PoE just for power only. The other issue is the outlet is only a 2 prong outlet. So my question is what exactly would I need to power it with PoE in terms of hardware as far as injectors and splitters? I know the loss would be minimal with lmr 400 but loss is loss.
Why don’t you just use a normal power cable for power?
For a POE, You need one injector and one splitter, e.g
The link shows the injector, splitter, both compliant with the POE standard, and a cheaper set, which isn’t.
The cheapest solution is a set like this https://www.amazon.com/Cable-Matters-Passive-Injector-Ethernet/dp/B01J6JP8XE/ref=pd_sim_147_4?_encoding=UTF8&pd_rd_i=B01J6JP8XE&pd_rd_r=5RNBJHYE5RZTK6GBJG22&pd_rd_w=IVLFu&pd_rd_wg=brIng&psc=1&refRID=5RNBJHYE5RZTK6GBJG22.
Not according to any POE-standard, but it seems to work as well. Not sure what is the max length, though.
The run is about 25 feet. if they have a power cable that long it would be an easy solution. suppose I could run an extension cord maybe
On second thoughts, a power cable is, well, a power cable, so there are probably a lot of things one has to keep in mind using them permanently outdoors, like grounding or a GFCI device?
That might also be true with regards to POE. Maybe a run of lm400 isn’t such a bad idea after all.
PoE will do what you want. Use a Pi with ethernet, don’t use WiFi.
You can get a single PoE injector, but I bought a switch so I can run two IP phones and a couple of Video cameras. Think ahead if you ever plan on having cameras. PoE is probably cheaper than coax, and it’s 48 volts and not 120 or 220 volts.
Feeding 5V on long PoE cable may cause excessive voltage drop and low voltage at RPi.
For long PoE cables, a 48V DC supply at router/switch, and a down convertor to 5V at RPi works satisfactorily.
https://s20.postimg.org/vprfnmi0t/Po_E_48_V.png
Below is one such complete kit. This item is given as an example for guidance only. If you search Amazon and eBay, you will find many other makes and prices.
https://www.amazon.com/itm/dp/B004UBUB7C
The kit contains:
Power Adapter AC to 48V DC
Power Cord
PoE Injector 48V DC
Ethernet Cable
PoE Splitter with integral down convertor to 12/9/5 V DC (dc output voltage selectable by a switch)
I power an odroid xu4 and a radarcape in my attic via Poe with 150ft cat 5 cable.
Just ensure the 5V is rated for 2.5 amps. It should work up to 330ft.
I use a switch to power the radarcape and 2 RPI3s in the basement.
The Odroid requires 4 amps so needed a POE + injector and splitter.
They have been running well for a year.
Awesome thanks! Do you know if the power adapter is 2 prong? the run is only going to be 25 feet:-)
I have just now checked the specs of TP-Link kit I gave as an example.
Overview: tp-link.com/en/products/deta … l#overview
Specs: tp-link.com/en/products/deta … ifications
I found it does not specify output power (W) or current (A) of splitter. It only specifies DC output current of 48V adapter.
Power Supply Unit of PoE Injector:
Input: 100~240VAC
Output: 48V, 0.5A Switching PSU
Output Power For PoE Splitter:
12/9/5VDC
I’m no technical expert, but for ‘remote power supply’ a friend of mine uses these two plugs (available in Germany) and an adequate cable for several meters:
I don’t know if similar USB plugs are offered in USA/Canada and what’s the maximum useable lenght (cable).
It’s just a suggestion …
The user’s manual for this says
12V/1A
9V/1A
5V/2A
Manual is here
static.tp-link.com/resources/doc … _Guide.pdf
POE is great. If possble, go for real, AF-compliant POE. It will only apply power after being “asked” for it, and will protect non-POE devices, if you plug them in.
Some cheap non-standard POE stuff WILL fry your non-POE devices if you forget, and plug them in without the POE splitter.
/M
AF-compliant:
Injector TP-Link TL-PoE150S
amazon.com/gp/aw/d/B001PS9E5I
Splitter TP-Link TL-PoE10R
amazon.com/gp/aw/d/B003CFATQK
Injector User Guide / Specs:
static.tp-link.com/resources/doc … _Guide.pdf
Splitter User Guide / Specs:
static.tp-link.com/resources/doc … _Guide.pdf
These work well, I have used a Zyxel PoE switch and 2x TL-PoE10R to power an Rpi system AND a FR24 receiver using the same Eth cable for a year now without any problems.
Beware. The “PoE Kit TL-POE200” amazon.com/dp/B004UBUB7C/re … UTF8&psc=1
often advertized together with the PoE150 and PoE10R is a cheaper version and NOT AF-compliant. It still works well, but should never be mixed with other units, and there is no guarantee that it will not damage a non-PoE device if plugged in by mistake. Also, it can NOT accept inline power (data + power on the same wires), necessary if you want to run PoE on 2 pairs.
It’s easy to think that the “Kit” is just the 2 the units together, but it’s not the same products!
/M
I note that someone has mentioned that its 2A @ 5V out below.
Having said that, thats the one I use on my portable setup and it works like a dream. You just need a 2.5mm DC plug to miniUSB to power the Pi.
If using this…
try…
shove 12-18v up the wire, then put one of these at the Pi end
ebay.com/itm/Micro-USB-OUTPU … 2363207559
Out of curiosity, I tested one of these cheap passive poe cable kits with a Raspbery Pi 2 with different cable length.
The results are rather disappointing, if not surprisingly so.
A 1m cable works fine, and with a quality 10m cable, the leds of the pi won’t show even the slightest flicker.
With a 5m cable, the RPi on its own starts and would probably work fine, but with a FA Orange stick (or a cheap oem stick, for that matter) it does not boot, and when plugged in later, the Pi immediatley shuts down. I tested this with two different power supplies, a 5V 2A and a 5V 3A power supply.
I guess the solution, as stated above, is feeding at a higher voltage and convert it back, which is the same thing these other kits are doing.
POE feeds at 48V. You should be fine up to 300ft/100m with quality components.
My runs are 150 ft and one device requires 4-5Amps so I had to go with POE+.
My cable is overkill, cat5e STP. UTP cat5 should be fine. I did try cat 6 STP but it was too think for the hole in the side of my house, at the time (I have since enlarged it to 1"/25mm).
We all know that, that is why we recommend at least active POE at 24 or 48 V (with down-conversion to 5V), or preferably AF-compliant POE which is always 48V on the cable.
/M
You are right, still, some people apparently found it useful (see amazon reviews), that’s why I checked it out, that is part of the fun (until you fry someting 
) .