This antenna type has the only advantage at being much smaller than ¼ wavelength monopole. Monopole at 160m would require 40m high antenna! Main disadvantage is its low efficiency; the larger the wavelength the higher are the losses. At 160m the losses are very high, but this is the only way to get antenna that can be mobile for that band.
The mast must be an insulator.
Height of the complete antenna is only 2190mm, for all the frequencies. Coil length is 2116mm, and there is the part of the mast at the bottom where wire from the coil goes straight down to the end of the mast (vertical green wire at the image below).