A novel 42-GHz-band low-noise downconverter for high-definition TV (HDTV) outside broadcast links has been developed. Commercially available HEMTs are used for a low-noise preamplifier, and the parasitic reactances of bonding wires were considered when designing the input and output matching circuits for the preamplifier. A gain of 10.2 dB and a noise figure of 3.6 dB were obtained with a two-stage HEMT amplifier. The local oscillator was a parallel-feedback HEMT oscillator that directly generated a 38-GHz-band signal and was stabilized by a spherical dielectric resonator. With an output power of more than 4 dBm, a frequency drift of 2 MHzp-p was obtained over an ambient temperature range of 0 to 40. From 41.5 to 42.0 GHz, the total noise figure of the downconverter was less than 5 dB.