This is a nice database on line:
to have updated HF informations

Even if you don't have a receiver:
you can listen anyway
SWL Projects and Documents
Antenna Active 8 Way Splitter HF RX
Home Made HF Receiver Matrix
Expert Splitter with Noise Killer
Basic Project for a Noise Cancelling
RX Balun Calculator HF Comparison
Loop Antenna from 50 to 90 cm
Half Wave Antenna from 10 to 15 Mhz
Stereo AM sample Audio and SDR Images
IF 9 Mhz Single Conversion HF Receiver
Diplexer for RX IF at 9 Mhz Home Made
Military Voltmeter Receiver
Matrix HF-144 Receiver 2020
Without listening,
there can not be dialogue !