  Note: This is a revised version of the paper that
_corrects_a_calculation_error in translating observed Jansky units to EIRP in
Watts. Mistakes are labeled below. Motivated by the hypothesis that Oumuamua
could conceivably be an interstellar probe, we used the Allen Telescope Array
to search for radio transmissions that would indicate a non-natural origin for
this object. Observations were made at radio frequencies between 1 and 10 GHz
using the Array's correlator receiver with a channel bandwidth of 100 kHz. In
frequency regions not corrupted by man-made interference, we find no signal
flux with frequency-dependent lower limits of 0.01 Jy at 1 GHz and 0.1 Jy at 7
GHz. For a putative isotropic object, these limits correspond to transmitter
powers of (was mistakenly 30 mW) 10 W and (was mistakenly 300 mW) 100 W,
respectively. In frequency ranges that are heavily utilized for satellite
communications, our sensitivity to weak signals is badly impinged, but we can
still place an upper limit of (was mistakenly 10 W) 3 kW for a transmitter on
the asteroid. For comparison and validation should a transmitter be discovered,
contemporaneous measurements were made on the solar system asteroids 2017 UZ
and 2017 WC with comparable sensitivities. Because they are closer to Earth, we
place upper limits on transmitter power to be 0.1 and 0.001 times the limits
for Oumuamua, respectively.
