Recently installed a door intercom, now I have a distinct hum on AM radio that sounds like a motor boat. Power comes from an Altronix 12v DC power supply. Possible the power supply cable or door to intercom wiring is acting as an antenna and broadcasting hum from power supply?
Thanks
Yes, it's possible. Try a 12V battery to power the intercom to see if you've still got hum. Got a portable AM radio? Should be able to zero on the source pretty easily if you're not absolutely sure it's the intercom.
Probably the easiest way to start looking for a fix is to use ferrite split beads. Get 1/2" hole split beads and put one or more over the bundle of cables coming out of the intercom wiring.
You can also try filtering the power supply with something like this:
-- Bobby G.
Have something to add? Share your thoughts — no account required.
Ask the community — no account required