Sometimes I just move the cursor to some transmissions which I could not hear (listening somewhere else) but I could see them, tune there and just wait that somebody will repeat the CQ.
My idea is to have possibility - to go back in time - for some transmissions that happened some time ago and the are visible only on the screen - have possibility to ..listen to them. Then I would immediately know if is it worth to call/wait for them to make CQ again or .. I have them already.
Theoretically SDR receivers have such possibility - not directly but they can save some part of the bandwidth in the IQ file and this file can be played later. You can scroll thru this file and listen to it like normal radio - tuning, filter applying, change mode etc.
This is not exactly what I need - I would like to go back immediately and hear transmission that happened a few seconds ago. So far I didn't find such software that has such possibility. I started even considerations to write my own but first research showed that used algorithms for signal processing (FFT) are not really friendly to use :))
I consider to get some SDR receivers for testing.....