In this video, John Fallows, VE6EY, author of the popular  “Making it up” blog, shows HF diversity tuning in action with excellent results.  He compares the performance of the low cost SDRplay RSPduo  dual-tuner SDR receiver very favourably with the highly acclaimed Apache Labs Anan 7000 DLE MkII SDR.

In this demonstration he uses two active loop antennas separated by approximated 100 feet (30 metres) as he receives a weak 25m band broadcast signal over a 13,000 km path.

Update later on October 23rd: Just after I posted this, John published his blog describing all this in detail: https://play.fallows.ca/wp/radio/software-defined-radio/anan-versus-rspduo-on-hf-surprising-results/

There’s also a great audio interview with John being interviewed on Hamradio Workbench Podcast.  John describes Diversity reception and how he sets up his antennas.  He covers the difference between array gain, diversity gain and phase diversity.   Start listening one hour and thirteen minutes into the podcast here: https://www.hamradioworkbench.com/podcast/hrwb-140-diversity-reception

(Starting at one hour 41 minutes and 45 seconds in to the podcast, John talks about how well the RSPduo and SDRuno do diversity 😉 )

Another great video posted in November:  Take a look at this excellent RSPduo demo over on the Italian SDRplay Facebook group – it shows how you can select between 2 HF stations transmitting on exactly the same frequency by adjusting the phase setting: https://www.facebook.com/100001379902566/videos/1209143166582349/