Reddit reviews Radar Handbook, Third Edition

Generally the options for hobby projects are limited in part because of

• The cost of equipment required to "do RF correctly and without insane frustration"
  
• there are significant legal limits on what you can broadcast and what power level (generally you are limited to 1W maximum and on some frequencies, it's less than that)
  
  The radar equation makes both of these especially problematic.
  
  In particularly the 1/r^(4) path power loss which means to get 1 µW received you need a factor of r^4 emitted which can easily become KW-->MW emitted.
  
  I learned radar by:
  
  

1. Being a SW/Ham radio person
   
2. Working for DOD on a test range using and repairing radar systems
   
3. Working at HP T&M (now Keysight) supporting SAs, VNAs, etc. and thus getting a ton of hands-on training
   
   A lot good general information is available at: Radar Basics
   
   The "bible" IMO is still Skolnik's Radar Handbook (table of contents - pdf)
   
   A lot of good info on test equipment and measurement techniques are available through Keysight Application Notes