Is that from Iriave? I have a TR-1A (IiRC) from 5-6 years ago. Do you have any documentation for your module?
EDIT: http://www.iriave.it/Datasheet/TR-2ArevB.pdf
It looks very similar to the TR-1A that I have (somewhere). They use a reed relay to disconnect the TX circuit when idle to avoid loading the network and attenuating other transmitters. Anand's advice re 50Hz is likely spot on.
Bookmarks