Hands down the PlutoSDR (a.k.a ADALM-PLUTO) has the best price/performance & support I've seen (and I've owned a BladeRF, LimeSDR and various RTL dongles as well).

The core radio chip itself (the AD9363) appears to be identical and/or a binned version of the AD9364 chip used in things like USRP Radios (i.e. the high-end standard bearer brand for SDR) and can be configurated to behave like it [1]. The unit price for the AD9364 chip (in low volumes) is around $200. The ENTIRE PlutoSDR is $150 and that includes a Zynq-7010 FPGA (which itself is not cheap)!

Because it's built by Analog Devices, it's generally well supported. It's designed as an educational tool so there are a lot of tutorials for beginners like PySDR. I really like the interfacing libraries (pyadi) that allow me to easily configure the SDR from a python notebook and pull an RX buffer into numpy and process away.

[1] https://wiki.analog.com/university/tools/pluto/users/customi... [2] https://pysdr.org/index.html

I've only used the RTL-SDR ones, so I can't offer any first-hand comparison. But for receive-only operations, the RTL-SDR dongles are cheap, readily available, compatible with many or most SDR related software packages, and basically "just work". YMMV, but one of those is probably where I'd suggest starting.

I've heard good things about the HackRF devices as well. The nice thing about those is that they're programmable transmitters as well, not just receivers. But they're a bit pricier as well, which is the downside. If I buy another SDR anytime soon, that will probably be the direction I go.

If you just want to _look_ at signals, a RTL-SDR kit with a basic dipole antenna (rabbit ears) and the USB dongle is like $35USD and readily available.

I would 100% recommend starting there. If you actually find yourself using it and/or enjoying it, then look at spending some more money.

If you do enjoy playing with SDR stuff, could also recommend getting an amateur radio license. Basic license is ridiculously easy to get and gives you access to legally transmit on a whole bunch of different frequency ranges and put you in contact with some other RF geeks.

I'm a big fan of my LimeSDR Minis: https://www.crowdsupply.com/lime-micro/limesdr-mini/

The SDR comparison table on that page above is useful too.

You can sometimes find a good deal on a HackRF as well. It has a freq range of 1mhz to 6ghz (rx/tx). The popular RTL-SDR only has 0.5mhz to 1.7ghz freq range (rx), but costs only about 1/4.

The SDR you actually own is the best one - the cheap Chinese ones are rubbish, don't get me wrong, but you can still do a hell of a lot with a little RTL-SDR

Analog Devices have some good offerings well up the price scale but I forgot if they start at DC

Depends on what you wanna do with it, but a Red Pitaya is pretty good. Wish I had that instead of the hackRF