new / looking for information (directions / literature)

hello. just a hobbyiest, but have a lot of black holes-of-information that i need to fill.

could someone please suggest some readings on the following topics? (preferrably online readings/literature...but will purchase some books if necessary).

-radar bands (why different freq/bands are used for different purposes); wave propigation, why x-band is so useful for fire control, etc

-submarine design (anything on submarines), especially with sonar (active and passive) design and 'how it all works'. anything regarding submarines

-anything else on submarines

more info requests to come, i'm sure. :)

thanks,
 
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