  The Five-hundred-meter Aperture Spherical radio Telescope (FAST) has been
running for several years. A new Ultra-Wide Bandwidth (UWB) receiver,
simultaneously covering 500-3300 MHz, has been mounted in the FAST feed cabin
and passed a series of observational tests. The whole UWB band is separated
into four independent bands. Each band has 1048576 channels in total, resulted
in a spectral resolution of 1 kHz. At 500-3300 MHz, the antenna gain is around
14.3-7.7 K/Jy, the aperture efficiency is around 0.56-0.30, the system
temperature is around 88-130 K, and the HPBW is around 7.6-1.6 arcmin. The
measured standard deviation of pointing accuracy is better than ~7.9 arcsec,
when zenith angle (ZA) is within 26.4deg. The sensitivity and stability of the
UWB receiver are confirmed to satisfy expectation by spectral observations,
e.g., HI and OH. The FAST UWB receiver already has a good performance for
taking sensitive observations in various scientific goals.
