You need to know what you are looking for before you can know what type of meter you will use. The best meter
for the job will be sensitive to the type of radiation you wish to measure and give you the type of information which
is useful to you. Listed below are some questions which will help you refine your decision:
Do I want to measure magnetic fields? Electric fields? Radiofrequency fields?
What frequencies am I most interested in: DC? 60 Hz? ELF? VLF? Microwave?
How sensitive do I need my meter to be?
How accurate do I need it to be? (higher accuracy = higher price)
Do I prefer analog (best for surveys and readings "on the go") or digital (higher accuracy)?
Do I need three axis, or can I get by with single axis?
What special features do I want: audible signal? Multiple capability? Portability? Cost?