I mentioned a year or more ago that I was enthusiastic about ‘propagation-triggered’ recording and Jukka, OH2BUA has really been very active in this area – take  a look over on  the SDRplay forum at his latest post – http://www.sdrplay.com/community/viewtopic.php?f=9&t=1839 where he gives his Fall 2017 update:

He writes about the “OH2BUA SWL Kit”  describing how it  “monitors ham radio digital (FT8 mode) traffic on 1.8MHz (160 meters) band. If it happens to hear nice DXs, it kicks a wideband MW-recording running in purpose to capture DX broadcasts. When the FT8 DX signals disappear, it stops the recording. For me, it works overnight, every night. I’ll do the harvesting next evening – IF something is recorded. In my case, it’s waiting for North American ham traffic, and aims to catch NA MW-broadcasts.” 

If you have any cool ways for post processing signals captured with the large bandwidth of an SDR receiver, then our forum is  a great way to publicise it, or to gather inputs from other potential contributors.