Bosch CCTV distance dilemna

I have a local client that has a campus with 8 buildings. Buildings

1 through 7 have all their CCTV piped over to building 1 via twisted pair, and the Bosch Bi-Phase over 18ga shielded twisted pair. All is good with 6 of the buildings. (building 8 has a completely different CCTV system)

Building 7 however has a single 25 pair Cat3 cable running 4 twisted pairs for cameras, TR560 and TT560 used for video, and a couple of pairs for Bosch Bi-Phase control. Video is weak and crappy, and control is non-existant. I measure about 400mv AC at the headend for control, like 4mv while joystick is moving at the building 7. Obviously this is not the right cable. It was installed maybe 3-5 years ago, no one at the site has seen it work, so we don't know if it ever did. Cable run is approx 1500 feet.

I have several options, I think, and wanted to see if anyone has any others.

Try to triple, quad, or more up the 24 gauge wires on the control, since we have so many spares. Hadn't tried that yet, but video sucks anyways.

Go with a fiber link between the buildings. The LTC 4628 and 4629 are quite pricy however.

Go with some sort of Ethernet converter for this 1 building. Keep in mind 4 cameras, 2 are PTZ Autodomes.

Add a small Bosch DVR at building 7, and monitor it at building 1

I had thought of running the video and control over to building 8, but it has AD cameras and a March DVR, and I don't think the DVR over in 8 can handle the AD and Bosch Autodomes using 2 different protocols for control.

Reply to
Silicon Sam
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. I looked at DVR-8K 8 channel DVR at building 7, since that DVR does support Bi-Phase. Then run a PC with viewing software over at building 1. Is this the best solution ya think?

Reply to
Silicon Sam

Very good point! Over long distances, you get "voltage drop". And the smaller the wire, the more the voltage drop! So the idea with longer distances is to use a larger gauge wire. Search the internet for the words...

voltage drop calculator

...and you can plug in a few numbers. See the results with different wire sizes and distances.

Then shielding will make for a more clear signal. A long wire acts as an antenna picking up all sorts of electrical "noise". Ground the shield at one end only to prevent "ground loops". More on these here...

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Reply to
Bill

Does a Faraday cage require grounding at one end? Of course, grounding at both ends can cause ground loops, but is external noise suppressed if niether end is grounded?

Best, Christopher

Reply to
Christopher Glaeser

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