I'll look around for examples of these that I want to ask about. Here are two for starters.
1) Yesterday I tuned from 30 to 85 MHz just to see what might pop up in that range, which I've never previously explored. This was with RSP2 attached to a discone antenna, with SDRUno. I basically just worked my way across this spectrum in intervals of about 1.5 MHz, which seemed to be the zoom limit of the frequency display.
While tuning, I noticed a quasi-signal that kept appearing in the center of the display (right above the two o's in the word "Zoom" on SDRUno's main window). I tried AM, FM, CW, USB/LSB, and couldn't make it out to be an actual signal. The fact that it appears dead in the center of every frequency segment I was tuning across was suspicious. It only seems to appear in certain frequency ranges -- I haven't seen it, for example, at HF or at higher VHF/UHF. Is this something going on inside the SDRplay? If so, is there an explanation for it? See screen print:
2) While tuning across HF with a longwire antenna, I've sometimes come across signals that appear to be real station that transmit "cascading" signals -- moving from high to low across a range of frequencies. Below is one that I found on 4.550 MHz. What are these?
(The cascading effect would be more obvious in a video clip -- are these ok to post?)
