The brightness temperatures of the main Galactic radio-loops at 22 MHz
  The average brightness temperatures and surface brightnesses at 22 MHz are derived for the four main Galactic radio-continuum loops (Loops I, II, III and IV, hereafter radio-loops). Also the radio-continuum spectra for the radio-loops are presented. Adding the average brightness temperatures at 22 MHz derived here with the average brightness temperatures derived from spectra published previously at 408, 820 and 1420 MHz we obtained clearly non-thermal spectral indices for all radio-loops. Our derived spectral indices are slightly shallower than those measured by previous works. 
D. Uro\v{s}evi\'c, V. Borka Jovanovi\'c
astro-ph.GA