The thing to note about the Ettis and Lime devices is that they're good for so much more other than just moving I/Q to your computer. They have powerful FPGAs that make it possible to do filtering and decoding and such in hardware.

If you're just looking to play around with radio, you don't need a device with these features -- not until you're much further along the learning curve. For any practical usage of these devices, it's assumed you have the wherewithal and radio background to build the pieces that it lacks; filtering, amplifiers, antennas and feedlines, and so on.

This is very much a professional device, and it's not meant to replace the common usage of $20 rtlsdr dongles within the hobbyist radio community.

Funny you say that - those are literally the two thing I've done with my SDR!

Tracking aircraft is pretty fascinating though, if you live near a reasonably busy airport (as I do). Decoding random remotes is also useful - I bought a couple of "Emergency Alarm Buttons", which are very simple battery-powered buttons. I can detect their press and my PC can then stop music, shut off lights, etc.

I've recently learned that the local displays on bus/tram-stops are updated via radio, so my next project is attempt to receive and decode this data. Getting real-time information about buses & trams arriving at the stops near my house. (I can already do this, and have a toy project with an ESP8266 device + LCD screen in my hallway, but that uses the Web-API. I like the idea of using radio-alone.)

Came here to ask this. I'm an extra-class ham but I've never done any SDR. Are these suitable for regular ham use for voice and digital modes? (assume you'd want a big amp)