Forget
Yes they were known as search meters and were in fact a signal strength meter and were normally operated by the FE.When plugged in to (I think) VHF#1, the gain was automatically increased.Strange setup because we monitored "guard " on VHF #3.
Personally I've used them about 5 times in anger and we found 3 downed aircraft, including 1 fatal in the Blue Mountains near Sydney.In most cases we were steered into the search site by ATC.
When Qantas was privatised the management decided to remove them.
Additionally to all the above mentioned lost aircraft, I seem to remember a ferry aircraft going down near Tahiti. The Qantas crew were talking to him all the way down and he was never heard of again. From memory the Captain of the Qantas aircraft was Ben S.
Wunwing