It's 1/2 wave antennas for each band and are tuned to 125MHz, 160Mhz and the tube in the middle 370MHz. The elements that points upwards are then a 1/4 wavelenght.
The speed of radiowaves are more or less 300 million meters per second. Millions are Mega, so divide 300 by the frequency in Mega Hz to get one full wavelenght in metric meters. Several elements in parallell will add capacitance and lower the resonance frequency and RF signals have up to a 5% delay when they travel over metal so all elements probably needs to be shorten 5-10%.
You can calculate the lenghts to match the frequencies you would like to optimize.