ZoneMinder Forums

old, slow, and ignorant but i got there
i replaced a composite analog camera with a ahd camera
the new camera had a lot of horizontal lines
over the next few days i changed the camera, cable ends, and power
no matter what combination it was always the same
then i tried another camera and had a great picture
so i mounted that camera and the picture was trash
then after a couple of days i realized the difference
when i had a good picture the camera was not mounted
just hanging from the cable
so i remounted the original camera with a block of wood and a plastic clamp
and a great picture
i made a permanent mount out of plastic to insulate the camera body from the structure
and a great picture
you probably guessed i was mounting to a metal building

4bf9gSBj wrote: ↑Wed Aug 21, 2024 3:55 pm you probably guessed i was mounting to a metal building

Sounds like you set up a ground-loop, where instead of one nicely designed analogue output at 50 or 75 ohms impedance driving a matched cable, terminated in a 50/75 ohm input, you injected a whole lot of noise down the shield of the cable in connecting two different bits of building together with your video link. The noise then gets coupled into the signal.

Your solution certainly works, but beware there could end up a potential difference between the ground of the camera (provided over a long cable from the DVR/PC end) and the grounding of the building. So, could get an interesting effect for anyone e.g. up a ladder leaning on the metal building and handling the camera. Tingles? Zaps? Thrown from ladder? Depending on the magnitude of any electrical leakage ...

This is often a problem e.g. for aerial fitters on roofs. House number 1 has their TV and earthing system. House number 2 next door has *their* system. And, sometimes they are not QUITE as earthed as they could be. Touching both antennas/masts at once, while on a roof, can be unpleasant when a fault current finds its way to true-earth via you!

the metal building is about 100 feet from the house
underground coax and romex from the previous millennia and previous owner
what do you suggest

Is earth/safety ground bonded to the outbuilding? IOW, is the romex properly terminated in a distribution panel?

dougmccrary wrote: ↑Wed Aug 21, 2024 8:06 pm Is earth/safety ground bonded to the outbuilding?

yes

dougmccrary wrote: ↑Wed Aug 21, 2024 8:06 pm IOW, is the romex properly terminated in a distribution panel?

yes

Is the ground at the same potential as neutral at the shed and the house?

You can use moca coaxial to ethernet adapters: https://www.howtogeek.com/834950/you-ca ... t-network/

I kind of hate these, as they can be expensive, and you can short them if you don't wire them properly, but I have one or two that is up and running.

There were some cheap ones on ebay a year or two ago, though I don't see them now.

The decent ones are altronix: https://www.altronix.com/products/eBridge1CRT https://www.altronix.com/library/pdf/da ... ge1CRT.pdf and expensive. There's a couple different types, There are multiple outputs. Do some research. Ideally you won't need 12V at the camera end. I think these only make sense if you are doing a few cameras, or have a lot of money. Running dedicated ethernet is always best if that's at all an option.

dougmccrary wrote: ↑Thu Aug 22, 2024 1:01 am Is the ground at the same potential as neutral at the shed and the house?

according to my old multimeter, yes

according to my old multimeter, yes

Weird. You checked volts and ohms?

BTW, I've had OK luck with Actiontec MoCA adapters.