Plain-language answer: A full-wave loop is a closed conductor with total electrical length near one wavelength at its design frequency.
Why it matters in the antenna
Shape, height, feedpoint, polarization, ground, and matching determine impedance and pattern; square, delta, and irregular loops differ.
What to verify
Reproduce the documented perimeter and geometry, keep supports from distorting it, and measure at the chosen feedpoint.
The common mistake
Calling any closed wire a full-wave loop on every band.
Operating boundary
Use the exact documented component, geometry, frequency, power, duty cycle, clearances, and feed/return system. Begin tests at low power and stop for heating, arcing, damaged insulation, or unstable supports.
