Network Video Technologies
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FAQs

Wire and Wiring
   
 
What kind of wire do I need to use with NVT devices?
Use Unshielded Twisted Pair, Category 2 or better, 16-24AWG, stranded or solid. Using a multi-pair wire (six pairs or more) with an overall shield is OK.

Can shielded twisted pair be used?
Some customers have successfully used shielded wire up to a few hundred feet. However NVT does not recommend it. Its high-frequency roll-off will severely degrade the distance performance. Use of an amplified receiver can compensate for some signal loss. Multi-pair wire (six pairs or more) can have an overall shield without degradation.

Can the wire path have splices?
Yes. NVT recommends designing CCTV systems in much the same way as phone/data systems are designed. You can splice the wire or use 66-blocks or 110-blocks to make connections. Video can be sent through a dozen of these connections without significant degradation.

Can I transmit more than one video signal in a multi-pair wire bundle?
Yes. One of the benefits of using NVT transceivers is interference rejection. NVT video signals can reside in the same wire bundle as multiple video signals, ringing telephones, Ethernet, 24VAC, RS-422, RS-485, etc.

Can Category 6 wire be used?
Yes. Unshielded Twisted Pair wire, Category 2 or better, can be used with NVT.

Can un-twisted wire be used?
Some customers have successfully used un-twisted wire at short distances. NVT does not recommend it due to its interference susceptibility.

Can I use spare pairs in an existing telephone system to transmit video using NVT devices?
Yes. One of the advantages of UTP CCTV is that the wiring for video can reside along with telephone system wiring. However, be sure to use “dry copper” pairs. There should be no dial-tone, 48 volts, loading coils, bridge-taps or switching on the chosen pairs.

Can I install my UTP bundle near RF antennas, flourescent lights, motors, generators, or high voltage?
Yes. The NVT signal is highly immune to interference, allowing it to be installed near these noise-generating sources. For life-safety and electrical code reasons, never install NVT in the same conduit as high-voltage wiring.

Supported Signals


Do NVT transceivers support “up the coax” pan/tilt/zoom controls?
Yes. When using passive transceivers to transmit and receive, "up the coax" control signals can be sent with the video up to 750'.

Can NVT devices transmit VGA?
Yes. The NTSC output of a VGA or SVGA scan converter can be transmitted using NVT.

How can I send video from one camera to more than one monitor using NVT?
There are a couple ways to accomplish this. One is to connect your video source to a distribution amplifier. This provides multiple video outputs for each input. Connect a transmitter and receiver to each wire run leading back to each monitor.

The alternate method is to send the video signal to the first monitor using a pair of transceivers. Then loop out of that monitor and use another pair of transceivers to continue on to the next monitor.
 
What is the supported bandwidth?
DC to 5 megahertz, clear channel

Do NVT transceivers support broadband RF/VHF/UHF?
No. Use demodulators and modulators to convert to baseband composite video.

Can I transmit satellite or cable TV using NVT transceivers?
No. NVT transceivers do not support the wide bandwidth cable TV signal. However, a single channel can be sent if a demodulator and modulator are used.

Can I transmit a multiplexed signal on unshielded twisted pair?
Yes. That baseband composite video signal is supported.

Can NVT transmit RS-422 or RS-485 signals?
RS-422 or RS-485 signals are hard-wired between the P/T/Z equipment and are not transmitted or received by NVT transceivers. The data signal may be sent on a wire pair within the same bundle as the video signal.

General


Are NVT transceivers rack mountable?
Yes. The NV-RM8/10 rack panel will hold up to ten of the 600 series transceivers or up to two 4-channel transceivers. NVT multi-channel hubs are also rack-mountable and include the necessary hardware.

Troubleshooting


When using the NV-652R, the green “signal present” light is lit, but the blue “power” light goes out and there is no video. What does this mean?
The NV-652R requires a floating power supply. Neither conductor of the power supply output should be grounded. Multiple NV-652Rs may share one power supply.

When transmitting video between passive NVT transceivers, the video is wavy and there is a dark bar that rolls upward on the monitor. Why?
This is the result of a ground loop. Use an amplified receiver (which has built-in ground lifting), or remove the ground at the camera end. Be sure that floating the camera conforms to local/regional and National Electrical Codes.

Why is the green light blinking on the active receiver? This usually indicates a poor connection along the wire path.

Why is there a double image in my video?
Faint shadows of the original signal shifting to the right, or “Ghosting” occurs when there is an impedance mismatch along the wire. Verify that the monitor is terminated with 75Ω (not in loop-through). Check for and remove any bridge-taps (another wire pair connected to the wire run).

Why does my video look like a scrambled Cable TV signal?
This typically indicates reversed polarity.