1055497-1 Datasheet, PDF (13/320 Pages) Tyco Electronics – RF Coax Products

Product Facts
■ Excellent for Broadband
Frequency Applications
■ Field Replaceable Gas
Discharge Tube
■ Available Interfaces
Facilitate Retrofit
Capabilities
■ Low VSWR up to 2.5GHz
■ Specialized White Bronze
Finish
RF Coax Connectors
Surge Protectors
Selection of a Lightning
Protection Device
At right are the basic
advantages and limitations
for both types of protection
to use in the proper selec-
tion for your application.
Advantages
■ Broadband
■ Allows DC bias on the transmission line.
(critical for applications using mast top
electronics.)
■ No harmonic passband
■ Ease of retrofitting antenna sights
■ GDT easily accessible for replacement
Limitations
■ Routine maintenance recommended
■ 3 GHZ maximum frequency
■ Initial pass-through voltage
These devices incorporate Gas Discharge
Tube (GDT) technology. A GDT is a
hermetically sealed tube containing an
inert gas. The tube is inserted in the side
of the device through an easily accessible
weather sealed port. During normal
operation the tube is inactive. When an
installation is struck by lightning, a high
voltage impulse will appear on the coaxial
line. As the impulse amplitude rises, a level
is reached where the impulse surpasses
the dynamic voltage threshold of the tube
and the electrodes arc over to discharge
the energy to ground. Prior to activation of
the tube, there will be a short period of time
where energy will be present on the line.
This residual pulse is equal to the dynamic
voltage threshold of the tube. The maxi-
mum impulse voltage a tube can handle
without discharging is referred to as the
impulse sparkover voltage. This capacity
of the GDT is quoted as follows:
Characteristic
Impulse
sparkover
voltage
Symbol Definition
U_zdyn
Dynamic
voltage
threshold
Impulse
Typical
Value
1kV/µS 650V
In the case of the referenced chart,
the voltage will rise at one kilovolt per
microsecond and the tube will fire after 650
nanoseconds. During activation a small
percentage of voltage (called arc voltage)
will still pass through. This will be approxi-
mately 30 volts. When the pulse subsides,
the tube again becomes inactive leaving a
small residual voltage on the line. A direct
lightning strike results in an impulse current
of high amplitude. The capability of a device
to protect a system is defined as the
impulse discharge current rating. This is
defined as the peak current of an impulse
which the device can withstand ten times
(5 at each polarity at fixed intervals) without
affecting the device. maximum impulse
discharge current is the peak current of an
impulse the device can withstand once.
Surge protectors are often used in applica-
tions requiring a standing DC line voltage.
This is typical in applications with mast top
electronics. The maximum voltage capacity
of a surge protector prior to it surpassing
the static voltage threshold and discharg-
ing it to ground is defined as its D.C.
Catalog 1307191
Revised 3-07
www.tycoelectronics.com
Dimensions are in millimeters
and inches unless otherwise
specified. Values in brackets
are standard equivalents.
Dimensions are shown for
reference purposes only.
Specifications subject
to change.
USA: 1-800-522-6752
Canada: 1-905-470-4425
Mexico: 01-800-733-8926
C. America: 52-55-1106-0803
13
South America: 55-11-2103-6000
Hong Kong: 852-2735-1628
Japan: 81-44-844-8013
UK: 44-8706-080-208