You might also want to try this. The extender uses either 910MHz or 933MHz and can be prone to interference. If you have a shoe box, line it with foil and put the extender in there leaving the top off and the box facing the Pronto. If reception gets better, then you likely have interference from surrounding equipment.
You can also download the manual from here.
[Link: files.remotecentral.com]Pages 9-11 discuss positioning.
Lyndel