Im using a Uctronics Gigabit poe splitter of amazon 
I have found you need to connect all to the pi first  then connect the cat 5 cable. then after a few seconds it powers up. if you do it the other way no  does not seem to work as well. i thing the switch need to sense the current draw.
As for antennas   Im using a mobile dualband vhf,uhf antenna for 433 and an 8di 868  grey pole antenna. both mounted atop of my radio mast on a cross beam.
I did try to use a cisco  power inserter. but that did not work  so i got a cheap poe  switch of amazon 
the other boards. one is planned for a remote location and the other to be fitted with a uhf beam  attached to my el/az  rotator. The plan if works. If a balloon is using horus on 433 and lora on 433, then horus gui  can control  a rotator just like satellite tracking