David Kaye
2014-09-28 19:14:19 UTC
If there were a ba.electronics I wouldn't feel so guilty about posting here,
but this topic is Bay Area and Internet-related.
Anyhow, I've replaced a video DVR unit and some cameras, and left others
intact. The previous DVR showed rolling hum bars on a couple screens and
occasional tearing on another. I mistakenly figured it was hum induced into
the co-ax from refrigerator motors and the like, but after turning off
various equipment throughout the restaurant I didn't get rid of the hum.
So, it's gotta be a ground loop issue. Most off-the-shelf CCTV systems I've
seen bring the camera power back to the DVR unit and supply from there, but
for some reason, the installer who put in the system years ago put up
individual 12v transformers at each camera. I'm not sure why, but that's
how things stand.
Now I need a bunch of ground loop isolation transformers to put at the DVR
end. Doesn't anybody keep these in stock in the Bay Area? I've looked them
up every which way and phoned everyone from Radio Shack to Fry's and Samy's,
and most folks either don't know what I'm talking about or they tell me I
have to mail order.
WAAAAAA!!! I miss Zack's! I want to be able to walk into a store and buy
some video isolation transformers (BNC to BNC) to get rid of my hum bars.
Is that too much to ask?
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but this topic is Bay Area and Internet-related.
Anyhow, I've replaced a video DVR unit and some cameras, and left others
intact. The previous DVR showed rolling hum bars on a couple screens and
occasional tearing on another. I mistakenly figured it was hum induced into
the co-ax from refrigerator motors and the like, but after turning off
various equipment throughout the restaurant I didn't get rid of the hum.
So, it's gotta be a ground loop issue. Most off-the-shelf CCTV systems I've
seen bring the camera power back to the DVR unit and supply from there, but
for some reason, the installer who put in the system years ago put up
individual 12v transformers at each camera. I'm not sure why, but that's
how things stand.
Now I need a bunch of ground loop isolation transformers to put at the DVR
end. Doesn't anybody keep these in stock in the Bay Area? I've looked them
up every which way and phoned everyone from Radio Shack to Fry's and Samy's,
and most folks either don't know what I'm talking about or they tell me I
have to mail order.
WAAAAAA!!! I miss Zack's! I want to be able to walk into a store and buy
some video isolation transformers (BNC to BNC) to get rid of my hum bars.
Is that too much to ask?
---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com