MrMark:
The receiver pictured in the original post is a regenerative receiver. Superheterodyne receivers perform considerably better and are drop in replacements.
jremington:
To maximize range with those cheap modules, dipole antennas work great. I get over 300 m line of site range with the setup below.Tip to tip length is 33 cm. Connect one end to "ANT" and the other to "GND".
Are you saying that attaching an aerial to the Gnd pin helps reception. Can you tell me how long the aerial would have to be if it has to be coiled.