If the POE-HAT has a polyfuse? That's an assumption
it probably does though.
, so what is your suggestion, just look at it and not bother ?
Write the idea off.
The question was can it provide the current (the PoE HAT) for the LNA.
The answer was maybe, if the HAT is specified like the PSU's.
I have no idea if the power into the Ethernet cable will be able to deliver enough to the HAT though.
I've never killed an SD card, with under Voltage/current, it gives you a warning or doesn't work and I drop both deliberately on a CC/CV 100w DC PSU.
It's a few quid though.
The voltage alterificators can have all their gubbins to protect the 5V gpio line from the LNA which it the thing needing 8 to 12V (and the LNB from that ?)
The RTL-SDR is sat on the USB, like any TV dongle does, it uses 5V from there, nowhere else.
I've not had one damage my Pi's or PCs.
Sometimes you just have to give it a go, see if it'll work or spend hours trying to find some special and then seeing if it works
He sounds like he understands what may/may not work.
Unless I have the setup wrong in my head of course
I guess it could/should be tested from a Pi 2.5A PSU via USB and then see the HAT spec when it in the shops as they cost more than the PSU.