  New VLA detections of the variable radio continuum source VLA
J181335.1$-$174957, associated with the energetic X-ray pulsar PSR~J1813$-$1749
and the TeV source HESS J1813-178, are presented. The radio source has a right
circular polarization of $\sim50\%$, and a negative spectral index of
$-1.3\pm0.1$, which show that it is non-thermal. The radio pulses of the pulsar
are not detected from additional Effelsberg observations at 1.4~GHz made within
one week of a VLA detection. This result would appear to support the idea that
the continuum radio emission detected with the VLA does not trace the
time-averaged emission pulses, as had previously been suggested. We discuss
other possible origins for the radio source, such as a pulsar wind,
magnetospheric emission, and a low-mass star companion. However, observations
made at higher frequencies by Camilo et al. (in preparation) show that the VLA
source is in fact the time-averaged pulsed emission and that the detection of
the pulses had not been achieved because this is the most scattered pulsar
known.

High Energy Astrophysical Phenomena