OK a bit of detail for you,
I'll leave the detailed description of how it works for the web page, in very basic terms its a loop antenna and sense antenna in one.
It's using a purple hulahoop to hold a wire loop. At the top of the wire loop is a break bridged with a 110 ohm resistor (2 x 220 ohm resistors in parallel).
Due to the resistance it doesn't need thick copper to make the loop, I used 1mm wire.
The loop ends feed to the terminals on the Loop Antenna Amplifier +. From one of the terminals run a wire down to an earth or ground rod at the base of the mast.
Do not connect the earth or ground wire to the BNC socket as it will bypass the common mode choke and isolation transformer in the amplifier.