  New multi-frequency radio observations of a large sample of radio-selected
BAL quasars, along with a very well matched sample of normal quasars, are
presented. The observations were made one immediately after the other at 4.9
and 8.4 GHz with the goal of measuring the radio spectral index of each source.
We have identified, for the first time, a significant difference in the
spectral index distributions of BAL versus non-BAL quasars, with BAL sources
showing an overabundance of steep-spectrum sources. This is the first direct
observation suggesting that BAL quasars are more likely to be seen farther from
the radio jet axis, although a range of orientations is needed to explain the
width of the distribution. Utilizing a few different relationships between
spectral index and viewing angle, we have also performed Monte-Carlo
simulations to quantify the viewing angle to these sources. We find that the
difference in the distributions of spectral index can be explained by allowing
the BAL sources to have viewing angles extending about 10 degrees farther from
the jet axis than non-BAL quasars.
