so ive been running an RTL-SDR v3 for about a year now mostly doing aircraft and some NOAA weather sat stuff and i keep going back and forth on whether to step up to something better for HF. the RTL-SDR does okay with the direct sampling mod but honestly its kind of a mess below 30 MHz, lots of birdies and the dynamic range just isnt there when there's a strong broadcast station nearby wiping out everything around it.

been looking at the HackRF One and the SDRplay RSPdx. the HackRF is half duplex which i understand but for just receiving thats fine. the RSPdx though has better specs on paper, 14-bit ADC vs the HackRF's 8-bit, and the noise figure is apparently way better in the HF range. but the HackRF covers way more bandwidth at once and its open hardware which appeals to me. price difference isnt huge maybe $50-80 depending where you get them.

main use would be HF, probably shortwave broadcast listening, some 40m and 80m ham band monitoring, and id like to try decoding some WSPR spots. not transmitting obviously. anyone gone through this comparison or have both? does the SDRplay actually make a noticeable difference on a real antenna or is it one of those things that only matters in lab conditions

Had both at the same time for a few months and yeah the RSPdx wins pretty handily on HF, its not even close to be honest. The 8-bit ADC on the hackrf sounds fine in theory until you have a 50kw broadcast station two MHz away and suddenly your whole band is unusable. The RSPdx handles that a lot better, not perfectly but way better. The HDR mode below 2 MHz is actually useful too if you ever want to do NDB hunting or mediumwave DX.

That said the HackRF is more fun to tinker with and if you want to do any transmit experiments later or play with stuff like portapack firmware it has a whole ecosystem. For pure receive on HF though the SDRplay is the better tool. SDRuno is a bit clunky but SDRplay also works fine with SDR# and HDSDR. If you're doing WSPR you'll probably end up in WSJT-X piping audio from whatever receiver software anyway so the frontend matters more than the software honestly.

the rtl-sdr v3 direct sampling always felt kinda half baked to me too, i used it for maybe two months before giving up on HF with it. went straight to an SDRplay RSP1A not the RSPdx and even that was a big jump. for wspr it works great, i just run it into SDR# with the audio piped to WSJT-X and it decodes fine on 40m. probably getting spots from 3000+ miles on a random wire in the attic so antenna matters more than people think with this stuff