For a forthcoming article, Owen Duffy asked me to make some measurements on my Alex Loop. 

For reference, here they are:

Date 12 September 2018.

Operating conditions: Suburban garden, locator IO83wg. Ground: wet grass. Height to bottom of loop conductor 1.2 metres.

Measuring instrument Youkits FG01 (SWR resolution 0.1,frequency resolution 1 kHz.

Fc = 7.014 MHz (1.1:1) Z = 51 Ohms (?)

Fl = 7.0085 MHz (2.0:1) interpolated

Fl = 7.0068 MHz (3.0:1) interpolated

Fu = 7.0195 MHz  (2.0:1) interpolated

Fu = 7.023 MHz (3.0:1)