Thank you Carl, I’ll give that a try and report back!
I was trying to use this exact same setup for a Meshtastic gateway and I was also experiencing the same behaviour on a PoE switch–buzzing, pulsing LED, etc. I thought the RAK PoE hat was defective. I managed to get it working by using a cheap “dumb PoE injector” from aliexpress. I also tested a Ubiquiti PoE injector and that worked just as well. The smart PoE switches do not work on this RAK device!
I also have a bunch of the feather wing PoE ethernet boards, and those work great on a smart PoE switch, running a very low current MCU (particle xenon nrf52), so I know it’s possible to create a PoE hat that works as it should; and it’s up to RAK to make this product work properly (maybe hire Patrick, link below, to advise them on their circuit)
Confirmed! 25ohm resister did the trick. I didn’t test the 100ohm resister, since this is a PoE build, I’m not too worried about being perfectly efficient on the power draw, so the 25 ohm is fine for me.
I soldered the 25 ohm resister to the connector pigtail I found:
I connected the pigtail with 25 ohm resister to the 5v output of the RAK 19018 and this is the Final build with resistor leads taped up and tucked away:
She powers up and runs perfectly now on my Ubiquiti PoE switch
Thanks for helping me solve this Carl!!
Awesome news @rkneeshaw !
Btw, I am not sure what is the power rating of your resistor but it will dissipate 1W continuously. Maybe at least 2W or even a bit bigger might better for long term outdoor deployment. Anyways, we can see its performance once out there 
Great idea, I did use a 1w resister (not on purpose) and it gets a bit warm. I’m going to switch to a 2w or even a 5w is the same price, will give a little more headroom.
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