I have been using PiAware with a Pro Stick Plus and this antenna https://www.amazon.com/Bingfu-100MHz-1800MHz-Magnetic-Compatible-Software/dp/B07HQJKMBD for a few years. The antenna and the Raspberry PI have been in my attic and I have gotten reasonable coverage out to about 50-60 nm. Recently I built a simple dipole antenna which I installed in the attic and moved the RPi down to the house, connecting them with RG6 coax and an amplifier. Now I can see aircraft out to 100 nm, but anything within about 5 nm is invisible. Because I live in a suburban area between two busy airports being able to see nearby traffic is very important to me, but I would also like to increase my coverage.
I tried connecting both antennas through a combiner, but it doesn’t work very well and upon thinking about it, there’s no way that it should. After doing a fair amount of research on this forum and other places to find an antenna that might work for me, it seems like there’s an inherent tradeoff between having an antenna that can see distant aircraft and one that can see ones right on top of you. You can’t have both. Designs like a dipole or collinear seem to have a lot of range and the monopole is great for seeing aircraft overhead especially if it doesn’t have a ground plane.
As an alternative I am thinking of getting a second ProStick Plus so that I can connect an antenna to each one and then merge the outputs of two instances of dump1090 running on the RPi. This would seem to be relatively straightforward and appeals to me more than spending time building DIY antennas since I have a lot more experience with software than RF. I would be interested to hear anybody’s thoughts or suggestions.