RLC-410 POE - Audio Hum

Camera RLC-410 POE powered, experimental traffic surveillance. First audio hum problem solved. Camera tested fine. When fixed in position on a tree it emitted a loud audio hum. This was caused by an earth ground loop as the camera was screwed directly into the tree. I presume that internally the case is used as a common earth, thus it set up interference with the audio stream. Fixing a non-conductive board to fix the camera too solved the issue. Please look up earth loop on the internet to understand what this is.

However, I still get a hum at night when the infrared lamps illuminate, as this goes away immediately daylight comes up. Anyone have any ideas of a fix for this? or is it an internal camera issue. It is not a software related problem as it appears in our main monitoring system Blue Iris as well as other systems.

FongJeng Kum

Hi,

I used to have this issue, but after I place a ferrite to the ethernet cable on the PoE injector and I don't get that humming sound anymore.

You can give that a try.

audrdem

Hi FongJeng Kum,

Maybe you can explain in more detail how you do it. "place a ferrite to the ethernet cable on the PoE injector"???

FongJeng Kum

This is the ferrite attached to the ethernet cable.

IMG_20170725_190159.jpg

audrdem

Sorry FongJeng Kum,
But from attached picture, I can't understand what for ferrite do you use and how do you use it.
Can it buy on ebay, or do it yourself? Maybe you can explain like for dummy
Thanks in advance

Audrius

FongJeng Kum

Yes, you can buy that from Amazon website.
I got mine for free when I purchased some devices that come with it.

It's not an expensive unit.

Audrius
A ferrite ring or clip on cable choke filters out unwanted high frequency noise signals (band pass filter) which can distort audio and other signals. It is simple, cheap and effective.

FongJeng Kum

Hope it helps for your end too.

audrdem

Thanks both