Achieving adequate coverage with high-gain antennas is crucial for fully utilizing the mmWave and sub-THz bands. This study reports indoor measurements at 140 GHz in Line-of-Sight (LOS) conditions within a corridor using a narrowband channel sounder. A 10° (24 dBi) receive horn antenna on a rotating platform and a 50° (10 dBi) transmit antenna were used. Path gain was modeled with a power-law, yielding an RMS error of 1.75 dB. Scattering degraded azimuth gain by up to 2.82 dB in the corridor with 90% probability.