We present the results of a mini-survey for associated H i 21-cm absorption at z \leq 0.42 with the Giant Metrewave Radio Telescope .
Our targets are radio galaxies , selected on the basis that the \lambda \approx 1216 Å luminosities are below L _ { UV } \sim 10 ^ { 23 } W Hz ^ { -1 } , above which there has never been a detection of 21-cm absorption .
Of the three sources for which we obtained good data , two are unclassified active galactic nuclei ( AGN ) and one is type-2 .
Being a non-detection , the type-2 object is consistent with our previous result that 21-cm absorption in radio sources is not dictated by unified schemes of AGN .
In the case of the detection , the absorption only occurs towards one of the two resolved radio lobes in PKS 1649–062 .
If the absorption is due to another intervening galaxy , or cool H i gas in the intergalactic medium , covering only the south-west lobe , then , being at the same redshift , this is likely to be gravitationally bound to the optical object identified as PKS 1649–062 .
If the absorption is due to an inclined disk centred between the lobes , intervening the SW lobe while being located behind the NE lobe , by assuming that it covers the emission peak at \approx 150 kpc from the nucleus , we estimate a dynamical mass of \approx 3 \times 10 ^ { 12 } M _ { \odot } for the disk .