[wkat4242]

> My findings were also that it's really super important to have them up high... at which point you need decent cable, termination and general radio knowledge otherwise you are exposing yourself to other issues.

Well, 1090 Mhz is a crap frequency to run through coax cable for long distances. The attenuation is pretty high at that frequency already. So I wouldn't just mount the antenna on the roof and then coax the RF down a few floors. You will reduce your range.

I would simply mount the SDR itself right up on top of the mast, along with a raspberry pi to decode everything. Then add a PoE HAT and all you need to bring down is Ethernet for which long distances are no issue. The PoE uses 48V so it also bypasses the problem of voltage drop on 5V with high current. Put it all in a waterproof box of course. Ideally metal for heat dissipation because waterproof means no airflow from outside to inside.

Make sure you use real copper Ethernet cable and not that CCA crap (copper clad aluminium) because that has much higher resistance and does have big problems with PoE. All the cheap cables are CCA these days so beware.