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M/A-COM, Inc.
North America:
Tel. (800) 366-2266
s
Asia/Pacific:
Tel. +85 2 2111 8088
s
Europe: Tel. +44 (1344) 869 595
Fax (800) 618-8883
Fax +85 2 2111 8087
Fax +44 (1344) 300 020
2
Specifications Subject to Change Without Notice.
RF Coaxial Lightning
& EMP Protection
Application Information
Ideal for use with GSM, PCS and DCS
Maintenance Free Operation
Low VSWR Within Specified Bandwidth
Configurations include direct attachments to
Cable variants
Optional White Bronze Finish
Description
/4 stub tuners are three port coaxial devices which employ a
short circuit element as a means of protection against lightning
or EMP strikes. The third port, extending from the side of the
main transmission path of the connector, is terminated in a
short circuit at a predetermined distance from the main path.
The distance is calculated to be exactly one quarter
wavelength ( /4) at the desired centering frequency (Fo).
In order to offer the most flexible solutions for infrastructure
applications, stub tuners are available in either an individual
connector format or as a cable assembly ready for direct
installation into a RF coaxial transmission line. A wide variety
of interface styles are available to meet existing retrofit or new
design requirements including Type N, and 7-16. Standard
crimp tooling is available to facilitate direct connector
termination to RG58 or low loss Times T-Flex 402 cables.
Application Information
The centering frequency is an important selection criteria
because /4 stub tuner design techniques restrict the
bandwidth in which acceptable VSWR performance can be
achieved. Stub tuners exhibit a v-shaped VSWR response.
Typically this bandwidth is 8% of the centering frequency.
Specified bandwidth in excess of 8% begins to experience
degradation of VSWR at the centering frequency. Stub tuners
are frequency specific in application as opposed to surge
protectors which address a wider spectrum of frequencies. As
a result of this restriction, M/A-COM offers a wide range of
standard stub tuner devices which address commonly
deployed cellular frequency bands such as GSM, NAMPS,
PCS 1900 and DCS 1800.
/4 Stub Tuners
Stub tuners, by the nature of their short circuit designs, do not
have a sparkover or residual voltage as found in surge
protectors. This ensures the greatest levels of protection
against repeated lightning or EMP strikes within specified
frequency bands. Stub tuners are also extremely reliable and
maintenance free since they contain no active parts. This
characteristic can be important when considering the total cost
of ownership, including the need for replacement or repair of
the device within difficult to reach infrastructure equipment.
Some alternative plating finishes are available with M/A-COM’s
Stub Tuner Lightning products. Standard plating finishes are
shown within the data sheet, but alternatives are available by
customer request. Details of M/A-COM’s new “White Bronze”
finish are shown in the application notes associated with this
data sheet. For more detailed information, please contact your
local M/A-COM field sales office.