Spectra of TMC-1 and L483 showing the emission lines assigned to the J = 5−4 and J = 10−9 rotational transitions of NCCNH⁺, lying at 44.4 GHz and 88.8 GHz, respectively. The rms of the spectra at 44.4 GHz is 0.0045 K per 12 kHz channel for both sources, while at 88.8 GHz the rms is 0.0029 K and 0.0088 K per 50 kHz channel, for TMC-1 and L483, respectively. The antenna temperature scale can be converted to main beam brightness temperature by dividing by (B_eff/F_eff), which takes a value of 0.36/0.90 for the Yebes 40 m telescope at 44.4 GHz and of 0.82/0.90 for the IRAM 30 m telescope at 88.8 GHz.