Phil G4UDU this morning posted a link to a tremendously useful Web resource called sigidwiki.com.
Translated back into English from Nerdish, this is a radio signal identification Wiki, something I'm sure all of us would potentially be interested in. We know that a Wiki is an online information resource built and maintained by its own user base, and so it's usually up to date and accurate because the curators are often passionate if not fanatical about managing certain information for the wider community.
This particular site is clearly dedicated to identifying radio signals of all types, and the Wiki is well organised by both frequency range and usage type.
I'll let you go and have a play with it, but it really doesn't take very long to (for example) identify the horrible Russian Over The Horizon radar signals currently splattering roughshod over not just our amateur bands, but all HF frequency ranges, without regard for any other spectrum users.
Usefully, you get to see a sample of what the signals look like on your spectrum waterfall, and also hear an audio sample. The audio is surprisingly helpful in differentiating similar-looking signals, often highlighting differences that are not immediately visually discernible.
Here you can see the entry for the 29B6 Russian 'Kontayner' radar:
which looks quite similar to the UK's very own PLUTO II OTH radar (based in Cyprus):
but you can clearly hear the difference. For political balance, it has to be said that it doesn't take much to find an awful lot of PLUTO II activity up and down the bands at the moment either, for obvious reasons I guess.
Military radar aside, there is an amazing collection of signal data in this database, so next time you see something unusual on the bands, why not screen grab it and go and look it up. It's particularly good at resolving digital signal types.