  We present the results of radio observations of the black hole binaries GRO
J1655-40 and XTE J1550-564 in quiescence, with the upgraded Australia Telescope
Compact Array. Neither system was detected. Radio flux density upper limits (3
sigma) of 26 micro Jy (at 5.5 GHz), 47 micro Jy (at 9 GHz) for GRO J1655-40,
and 1.4 mJy (at 1.75 GHz), 27 micro Jy (at 5.5 GHz), 47 micro Jy (at 9 GHz) for
XTE J1550-564 were measured. In conjunction with quasi-simultaneous Chandra
X-ray observations (in the case of GRO J1655-40) and Faulkes Telescope optical
observations (XTE J1550-564) we find that these systems provide the first
evidence of relatively `radio quiet' black hole binaries at low luminosities;
indicating that the scatter observed in the hard state X-ray:radio correlation
at higher luminosities may also extend towards quiescent levels.
