So ive been using a cheap RTL-SDR dongle for about a year now, mostly just listening to NOAA weather and poking around the local repeaters, and im starting to hit the limits of it. The noise floor is pretty bad above like 500MHz and i cant transmit obviously which sometimes i wish i could for testing purposes.

Been looking at either grabbing a HackRF One or stepping up to an SDRplay RSP1B or maybe the RSPdx. The price gap is real though. HackRF is around 300-350 for a legit one and the RSPdx is similar but the SDRplay stuff seems way more focused on receive quality from what ive read. The HackRF does TX which is appealing but the ADC resolution is only 8 bit which apparently matters a lot for weak signal work.

Mostly want to use it with SDR++ or maybe HDSDR, pick up some utility stuff, maybe decode some satelite signals, and eventually do some passive radar experiments ive seen people do. Anyone gone through this decision and have thoughts? Did the SDRplay actually make a noticeable difference in what you could hear vs a decent RTL-SDR with a good LNA in front of it?

honestly the SDRplay is night and day compared to an RTL dongle, even with an LNA. the 12 bit ADC on the RSP stuff just handles crowded band conditions so much better, like if you live near an FM broadcast transmitter you'll know what i mean, the RTL just gets completely blasted and even with a good bandstop filter it's a pain. the RSPdx specifically has some nice HF coverage improvements too if you care about anything below 30MHz.

that said if you actually want to transmit for testing the HackRF is your only real option in that price range, the TX power is garbage but it works for loopback stuff and close-range experiments. i have both at this point which probably says something about how this hobby goes. started with a v3 RTL dongle, then got a HackRF, then got the RSP1A and honestly the RSP1A just sits on the desk doing ADS-B and ACARS all day and barely gets touched for anything else because it's just solid. SDR++ works great with all of them btw, way better than SDRsharp these days in my opinion.

Passive radar with a single HackRF is gonna be tricky, you usually want two coherent receivers for that. There's some work been done with the KerberosSDR for that kind of thing, might be worth looking into before you commit to the HackRF path if that's a main goal.