Nitek VH851 User manual

5410 Newport Dr #24 • Rolling Meadows, IL 60008
PHONE [phone] • FAX [phone]
Internet: www.nitek.net • E-mail:[email protected]
Installation and
Operation Manual
VH851
VH1651
Rev 091903
NITEK ®

TABLE OF CONTENTS
Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
System Specifications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Limited Warranty. . . . . . . . . . . . . . . . . . . . . . . . . . 5
VH1651 Diagram. . . . . . . . . . . . . . . . . . . . . . . . . . 6
Page
Reduce risk of fire or electrical shock do
not expose this product to rain or moisture.

Features of the VH851 and VH1651
❒Live video over twisted pair lines for up to 1,500 feet
❒Easy to install with just a screwdriver
❒High resolution color or monochrome video
❒Virtually impervious to hum and noise
Page 1

System Specifications
Page 2
VH851 System includes the following:
(1) VH851 Hub
(1) Wall power transformer
VH1651 System includes the following:
(1) VH1651 Hub
(1) Wall power transformer
Size 1.75"H x 17"W x 6.0"D
Power Requirements 24VAC, 50/60Hz, Class 2
@550mA
Input Low voltage current loop from
balanced UTP transmitters
Output-Video 1.0 vpp composite video
Monochrome or Color

Page 3
The VH851 and VH1651 UTP Video Receiver Hubs are
designed to receive standard UTP video and output
standard coax video.
Step 1)
Checkthetwistedpairforcontinuity.Dothisbyshorting
thepairofwiresatone end andusean ohm metertocheck the
resistance at the other end. Also, use a multimeter to test the
line tomakesurethereisnovoltageonit. Thechartbelowwill
give you the length of your wires for a measured resistance.
Testingeachlineandrecordingthelengthforeachcamerarun
can greatly reduce installation time.
For distances greater than 1,500 feet other long range
units may be needed.
Step 2)
Connect the twisted pair from each transmitter to the
screw terminals noting the polarity of the connection. If the
wiresarereversedthevideowillbeunviewableonthemonitor.
Reversing the wires will not damage the unit.
Step 3)
The VH851 and VH1651 are powered from a 24VAC
wall pack. In the case of several units a larger central supply
maybe used. Contact NITEK®TechSupport forrecommenda-
tions. It is recommended that each video out BNC jack be
connectedtoatestmonitorfirstforthepurposeofadjustingthe
receivers. After having adjusted each receiver, connect them
to the rest of your video system.
Installation
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Page 4
Installation - continued
Step 4)
Remove the front panel of the VH851 or VH1651 by
pulling the knobs toward you. Inside locate the receiver unit to
matchthecamerayouareworkingon.SettheDIPswitchesfor
your camera distance as listed below, use the setting closest
to your actual cable length. If you have no video or a streak
through your video your wire pair may be reversed. When
finished replace the front panel and lock it in place by pushing
the knobs in.
The settings listed are for normal conditions. Other set-
tings are possible. For added sharpness adjust switches 7
and 8. For more gain adjust 5 and 6. Switches 1 and 2 or 3
and 4 must be operated in pairs to adjust for frequency
compensation.
Step 5)
There is also an “Earth Ground” terminal on the rear of
theVH1651,thisconnectionprovidesimprovedsurgeprotction,
it is not required for operation. If the “Earth Ground” is not
connected the unit will be grounded through the coax shield.
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Page 5
Troubleshooting
Video inverted or rolling and unstable.
• Reverse the wires of the twisted pair at either
the transmitter or receiver.
No video out at the receiver.
• Check to make sure that there is video in at
the transmit end.
• Make sure that the pair of wires you are using
is not open or shorted between the transmit
and receiver points.
• Check power to the receiver.
Ghost image at the receiver.
• Bridge tap or "T" tap on the twisted pair video
line. Remove tap.
For additional help with problems please call NITEK®Tech-
nical Assistance at [phone]. Hours are from 8am to
5pm Central Standard Time Monday through Friday. We are
always ready to help.
Problem
Fix/Cause
Problem
Fix/Cause
Limited Warranty
NITEK®warranties that this unit will be free from defects in
materials and/or workmanship. Defective units will be re-
pairedorreplacedatouroption within2 yearsfrom thedate of
shipment. This warranty does not apply to units abused
through misuse or subjected to improper and/or excessive
voltage, beyond our control.
For complete warranty details contact NITEK®
Problem
Fix/Cause

Page 6
VH1651 Back
VH1651 Top
*Note: VH851 is identical with the
exception of 8 BNC ports instead of 16
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1624VAC
450 mA 50/60 Hz
Class 2 only
+
-
+
-
24
+
-
+
-
68
+
-
+
-
10 12
+
-
+
-
14 16
5.0
"
6.0"
17.0"
1.7
5"