  We report measurements of microwave spectra of two-dimensional electron
systems hosted in dilute Al alloy, Al$_x$Ga$_{1-x}$As, for a range of Landau
level fillings, $\nu$, around 1. For $\nu>0.8$ or $\nu<1.2$, the samples
exhibit a microwave resonance whose frequency decreases as $\nu$ moves away
from 1. A resonance with this behavior is the signature of solids of
quasiparticles or -holes in the partially occupied Landau level, which was
previously seen in ultralow disorder samples. For $\nu<0.8$ down to as low as
$\nu=0.54$, a resonance in the spectra is still present in the Al
alloy-disordered samples, though it is partially or completely suppressed at
$\nu=3/5$ and $1/2$, and is strongly damped over much of this $\nu$ range. The
resonance also shows a striking enhancement in peak frequency for $\nu$ just
below 3/4. We discuss possible explanations of the resonance behavior for
$\nu<0.8$ in terms of the composite fermion picture.
