Did you read how i put a Mikrotik Sextant in a pot or how i use Mobile PoE via USB for upto 5V devices like Ubiquiti? If not, here i'll describe how to power a Mikrotik RouterBoard via PoE and USB. I came up with this idea after the success with using a Bullet on the go, so i was curious if that would be possible with a RouterBoard SXT 5HPnd too. Initially i just tried the same cable i used for Ubiquiti but it seemed the SXT doesn't get enough volts because it reboots a few seconds after powering on. Using two USB-Ports wouldnt help as this just doubles the mA, not the voltage. Simple like it is for Ubiquiti, its not that simple for Mikrotik, but with a small addition to the cable it works also to power the SXT.
While understanding how Ubiquiti works with DC-DC step-down converters for PoE and googling for similar products i noticed there are also different DC-DC step-up converter available. Sure while raising volts, it would "lose" milliamps but as i wasn't sure whether it would be enough current, i thought its not expensive anyways and worth a try to power the SXT.
First cut an USB cable with fitting plug and remove all wires except red and black. Dismantle both, attach the red one where it writes "IN+" and the black one where it writes "IN-".
Because the DC-DC converter has adjustable voltage, you have to measure how much output voltage is set and change it according your needs.
Turn it carefully clockwise to decrease output voltage or counter-clockwise to increase it.
With the volmeter measure on pin 1 and 4 to get the output voltage.
From the RouterBoard website the SXT powers with 9-30V, while the manual says 8-30V. When i set 8 volts output, the SXT boots, initializes network and reboots after the link is established.
Increasing to 9 volts helped to get it stable powered on.
Remember the cable from Mobile PoE via USB for upto 5V devices like Ubiquiti? Connect it to the USB port of the DC-DC converter and give it a try! Seems to work, still i need to test outdoors to see how wifi works with this solution.