Radio spectrum of B1834+620. Red dots represent the measurements of the flux densities for the four components at 144 MHz (LOFAR, this paper), and 612, 845, 1400, and 8460 MHz (WSRT and VLA Schoenmakers et al. 2000a; Brocksopp et al. 2011). The blue line indicates the fit with a Continuous Injection model (CI).