I forgot that is amateur radio 33cm band. Certainly looks like a mess lol. I found something on 1288.5000mhz as well I just took a snap of it instead of recording it. 2nd image it is much stronger around 1314.5 mhz902-928 MHz is shared Amateur, ISM (Industrial, Scientific and Medical) and Radiolocation. It is also called the "junk band". The signal you are receiving could be a lot of things.
I tried to rule it out but it moves with the dial normally. If it wasn't there it would disappear as it gets closer to the center of the display.I don't have a SDR but I have read that they must be configured properly.
Have you ruled out the possibility that some of these signals don't actually exist?
What kind of antenna?
How far is the antenna from the computer and other electronic devices?
Google is useless if you don't know what you are looking for.I see this daily and I cannot figure out what to type into Google to try to find out what this wild mess is
I got the FCC Table. 1300-1350mhz it shows Aeronautical Aviation, Radio Location, and Radio Navigation- Satellite. I am convinced it is Aeronautical.It falls in the list as well on this site https://aviationglossary.com/aviation-frequency-bands-united-states/Google is useless if you don't know what you are looking for.
Check out some of the links on this page https://wiki.radioreference.com/index.php/Radio_Spectrum_Management_and_Allocations
That will get you to the FCC Online Table, US Spectrum Allocation chart, and other info about the types of users in different parts of the radio spectrum.