Basics(Edit)

Signal Tracer and Injector

RF Probe

Marker Tone Generator

Wikipedia: Audio Quality Measurement

Antennas(Edit)

Smart Dummy Load

Cheap Antenna Tuner with SWR Meter

W8WWV - Analyzing Three Antenna Analyzers

Component Test(Edit)

LC Meter (PIC-based)

Very simple field strength meter

-or-

MkI

Robustness test; see application: