Originally Posted by strider3700
Ran into an interesting problem while getting temperature sensors to the two kids bedrooms...
If it's not something obvious like an open connection, you might be picking up noise from the AC wiring in your house.
Long low-voltage audio runs have to contend with this all the time. Microphones that have long lines use a "balanced" cable that has twin conductors inside a ground shield. Regular balanced microphone cable can get pretty expensive, but I have seen a version of it that is about 1/8" in diameter.
Might help you out.