Not at all. At home I have a cheapo Adafruit RTL-SDR ($22 at Microcenter https://www.microcenter.com/product/463176/adafruit-industri...) running on an unused Gigabyte Brix. At my parents' I have a similar SDR on a Raspberry Pi. They're both indoors on the highest floor.

I have a LimeSDR as well that I screw around with sometimes, but really any basic receiver will get the job done.

I'm planning on checking out adsbexchange and FlightAware based on the comments.

The setup on the Brix: https://photos.app.goo.gl/dJmvM3R9u3eGpggP8

Project Loon balloons on Flightradar24: https://photos.app.goo.gl/b8wDkTn6XaRmUWGw6