I setup my RTL-SDR-v3 for HF on #Linux using #SDR ++. Used a 40m EFHW badly strung 5ft off the ground around the garden in #NVIS configuration. I was able to pick up CW from CA, NV, AZ and CA<->TX SSB. Also FT8 and JS8. Problem: on the #CW end of the band, I’m picking up an AM station which I assume is coming in via IF. Do I need real ground? or better common mode choke? Please advise. Having sold my bulky G90, I will use SDR, learn CW and get QCX once I can “hear” :)

followup:

@stefanfendt Thanks for notes! Got it. This SDR working in Q-sampling mode (despite sdr++ UI showing disabled - it auto-enables it for HF), but as you noted I’ll still need bandpass filter. Will check out how much one for 40m costs, or if another SDR model can be had for less and has front-end filters built in. …SDRplay does!

followup:

@stefanfendt which one would you buy? - broadcast interference filter: https://www.k9dp.com/shop/qrp-bci-filter/ k9dp.com/shop/qrp-bci-filter/ OR - 40m band pass filter: https://www.k9dp.com/shop/qrp-bandpass-filter/ (I’m only interested in 40m so ~flexibility is not a factor)