  When dealing with Fourier expansions using the third Jackson (also known as
Hahn-Exton) $q$-Bessel function, the corresponding positive zeros $j_{k\nu}$
and the "shifted" zeros, $qj_{k\nu}$, among others, play an essential role.
Mixing classical analysis with $q$-analysis we were able to prove asymptotic
relations between those zeros and the "shifted" ones, as well as the asymptotic
behavior of the third Jackson $q$-Bessel function when computed on the
"shifted" zeros. A version of a $q$-analogue of the Riemann-Lebesgue theorem
within the scope of basic Fourier-Bessel expansions is also exhibited.
