Well, Simon, i'd just say hunt n seek and go wild, that's a lot a band span to cover, which i say with absolute certainty you'll find plenty of everything and stuff you'd never want to admit to knowing about let alone admit to listening to.
As for the receiver, if you respect the inherent limits of the receiver re potential overload of the front end when it comes to some very strong sigs combined with the dreaded RX pre-amp i believe the ML30 has built in (i'm assuming it's not a 'proper' comms grade receiver), it's possibly a good candidate to pair with a switchable set of RX convertor modules, so you could easily touch into VLF and above 50 Mhz cheaply.
I have a generic brand ML equiv to the ML30, of which i removed the pre-amp since my HF receiver was plenty sensitive enough and i hate preamps, and i've tested it as a passive with lots of sizes of loops, from huge to tiny, from hair thick to really heavy duty wires and just about as many tube sizes i could get hold of, and with due credit - it's a bargain for what you get at stock.
I mostly use mine to listen to VLF stuff, mostly telegraphy.
Today at 9:49 pm by 
Subject: Cheap receiver with ML30 