Cisco 2.4-GHz Swivel-Mount Dipole Antenna... User manual

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© 2005 Cisco Systems, Inc. All rights reserved.
Cisco Systems, Inc., 170 West Tasman Drive, San Jose, CA 95134-1706 USA
Cisco 2.4-GHz Swivel-Mount Dipole Antenna
(23.7786.51)
This document outlines the specifications for and describes the 23.7786.51 2.4-GHz swivel-mount
dipole antenna and contains the following sections:
•Cisco 90-Day Limited Hardware Warranty Terms, page 1
•Overview, page 4
•Technical Specifications, page 4
•System Requirements, page 6
•Installation Notes, page 6
•Safety Instructions, page 8
•Obtaining Documentation, page 8
•Documentation Feedback, page 9
•Cisco Product Security Overview, page 10
•Obtaining Technical Assistance, page 10
•Obtaining Additional Publications and Information, page 12
Note The 23.7786.51 2.4-GHz swivel-mount dipole antenna is only shipped with a new router, and is not
available as a spare antenna. For an equivalent separately orderable antenna, use the AIR-ANT4941.
Cisco 90-Day Limited Hardware Warranty Terms
There are special terms applicable to your hardware warranty and various services that you can use
during the warranty period. Your formal Warranty Statement, including the warranties and license
agreements applicable to Cisco software, is available on Cisco.com. Follow these steps to access and
download the Cisco Information Packet and your warranty and license agreements from Cisco.com.
1. Launch your browser, and go to this URL:
http://www.cisco.com/univercd/cc/td/doc/es_inpck/cetrans.htm

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Cisco 90-Day Limited Hardware Warranty Terms
The Warranties and License Agreements page appears.

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Cisco 90-Day Limited Hardware Warranty Terms
2. To read the Cisco Information Packet, follow these steps:
a. Click the Information Packet Number field, and make sure that the part number
78-5235-03A0 is highlighted.
b. Select the language in which you would like to read the document.
c. Click Go.
The Cisco Limited Warranty and Software License page from the Information Packet appears.
d. Read the document online, or click the PDF icon to download and print the document in Adobe
Portable Document Format (PDF).
Note You must have Adobe Acrobat Reader to view and print PDF files. You can download
the reader from Adobe’s website: http://www.adobe.com
3. To read translated and localized warranty information about your product, follow these steps:
a. Enter this part number in the Warranty Document Number field:
78-5236-01C0
b. Select the language in which you would like to read the document.
c. Click Go.
The Cisco warranty page appears.
d. Review the document online, or click the PDF icon to download and print the document in
Adobe Portable Document Format (PDF).
You can also contact the Cisco service and support website for assistance:
http://www.cisco.com/public/Support_root.shtml.
Duration of Hardware Warranty
Ninety (90) days.
Replacement, Repair, or Refund Policy for Hardware
Cisco or its service center will use commercially reasonable efforts to ship a replacement part within ten
(10) working days after receipt of a Return Materials Authorization (RMA) request. Actual delivery
times can vary, depending on the customer location.
Cisco reserves the right to refund the purchase price as its exclusive warranty remedy.
To Receive a Return Materials Authorization (RMA) Number
Contact the company from whom you purchased the product. If you purchased the product directly from
Cisco, contact your Cisco Sales and Service Representative.
Complete the information below, and keep it for reference:
Company product purchased from
Company telephone number
Product model number
Product serial number
Maintenance contract number

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Overview
Overview
The 23.7786.51 antenna operates in the 2.4-GHz band, and is designed for use with spatial-diversity
access point (AP) systems. The 23.7786.51 antenna is compatible with Cisco 802.11b/g radio products
using a reverse-polarity threaded Neill-Concelman (RP-TNC) connector.
Figure 1 shows the 23.7786.51 antenna.
Figure 1 Cisco 23.7786.51 Antenna
Technical Specifications
The following table lists the technical specifications for the 23.7786.51 antenna.
74574
Antenna type Dipole
Operating frequency range 2400 to 2500 MHz
Maximum VSWR1bandwidth 2.0:1
Peak gain 2.2 dBi
Polarization Linear (vertical)
Azimuth plane beamwidth Omnidirectional
Elevation plane 3 dB beamwidth (H-plane) Omnidirectional
Elevation plane 3 dB beamwidth (E-plane) 55 degrees
Maximum dimensions 6.4 x 0.5 in. (162 x 13 mm)
Weight 0.1 lb (0.05 kg)
Connector type RP-TNC
Enclosure ABS

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Technical Specifications
Figure 2 shows the H-plane radiation pattern at 2.4- to 2.5-GHz for the 23.7786.51 antenna.
Figure 2 H-Plane Pattern at 2.4- to 2.5-GHz
Environment Indoor
Mounting Direct
1. VSWR = voltage standing wave ratio
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System Requirements
Figure 3 shows the E-plane radiation pattern at 2.4- to 2.5-GHz for the 23.7786.51 antenna.
Figure 3 E-Plane Pattern at 2.4- to 2.5-GHz
System Requirements
The 23.7786.51 antenna requires a Cisco 802.11b/g radio product that uses an RP-TNC connector.
Installation Notes
This antenna is designed to be mounted directly to the access point. For information about orienting the
dipole antenna, see the hardware installation guide for your access point.
In addition to antenna orientation, wireless access point installation location with respect to all wireless
clients plays a significant role in determining overall network performance. Clients at the furthest
coverage points might have 10% to 50% of the bandwidth of clients close to it. Wireless network
coverage in one area or location might need to be lowered to improve the performance of other clients.
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Cisco 2.4-GHz Swivel-Mount Dipole Antenna (23.7786.51)
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Installation Notes
Because antennas transmit and receive radio signals, their performance can be adversely affected by the
surrounding environment including distance between access point and client, physical obstructions, or
radio frequency (RF) interference.
Follow these guidelines to ensure the best possible performance:
•Wherever possible, mount the AP HWIC and antenna where the wireless devices would be within
sight and avoid physical obstructions. Barriers along the line of sight between client and access point
will degrade the wireless radio signals. AP HWICs and antennas can be installed above floor level
in office environments or near the ceiling for better performance since most obstructions tend to be
near floor level.
•The density of the materials used in a building's construction determines the number of walls the
signal must pass through and still maintain adequate coverage. Consider the following before
choosing the location to install your antenna:
– Paper and vinyl walls have very little effect on signal penetration.
– Solid and precast concrete walls limit signal penetration to one or two walls without degrading
coverage.
– Concrete and wood block walls limit signal penetration to three or four walls.
– A signal can penetrate five or six walls constructed of drywall or wood.
– A thick metal wall or wire-mesh stucco walls causes signals to reflect back and cause poor
penetration.
•Avoid mounting the antenna next to a column or vertical support that could create a shadow zone
and reduce the coverage area.
•Keep the antenna away from reflective metal objects such as heating and air-conditioning ducts,
large ceiling trusses, building superstructures, and major power cabling runs. If necessary, use an
extension cable to relocate the antenna away from these obstructions.
Caution Install the AP HWIC and any antennas away from appliances that share the same frequency bands.
Microwave ovens, cordless telephones, and security monitors can temporarily interfere with wireless
performance.
Caution We recommend you avoid installing wireless antennas in or near rack-mounted installations that include
networking equipment and computer servers whose radiated noise emissions can severely degrade radio
performance.
Note If the desired installation site has a marginally acceptable level of radiated noise emissions, consider
using a remote-mounted antenna, such as a wall-mount or ceiling-mount antenna, for better radio
performance and coverage.

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Safety Instructions
Safety Instructions
Follow these safety instructions when installing your antenna.
Warning In order to comply with FCC radio frequency (RF) exposure limits, antennas should be located at a
minimum of 7.9 inches (20 cm) or more from the body of all persons. Statement 332
•Plan your installation procedure carefully and completely before you begin.
•If you are installing an antenna for the first time, for your own safety as well as that of others, seek
professional assistance. Consult your dealer, who can explain which mounting method to use for the
location where you intend to install the antenna.
•Choose your installation site with safety as well as performance in mind. Remember that electric
power cables and telephone lines look alike. For your safety, assume that any line is an electric
power line until determined otherwise.
•Call your local power company or building maintenance organization if you are unsure about cables
close to your mounting location.
•When installing your antenna, do not use a metal ladder. Do dress properly: shoes with rubber soles
and heels, rubber gloves, and a long-sleeved shirt or jacket.
•If an accident or emergency occurs with the power lines, call for qualified emergency help
immediately.
Obtaining Documentation
Cisco documentation and additional literature are available on Cisco.com. Cisco also provides several
ways to obtain technical assistance and other technical resources. These sections explain how to obtain
technical information from Cisco Systems.
Cisco.com
You can access the most current Cisco documentation at this URL:
http://www.cisco.com/univercd/home/home.htm
You can access the Cisco website at this URL:
http://www.cisco.com
You can access international Cisco websites at this URL:
http://www.cisco.com/public/countries_languages.shtml

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Cisco 2.4-GHz Swivel-Mount Dipole Antenna (23.7786.51)
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Documentation Feedback
Documentation DVD
Cisco documentation and additional literature are available in a Documentation DVD package, which
may have shipped with your product. The Documentation DVD is updated regularly and may be more
current than printed documentation. The Documentation DVD package is available as a single unit.
Registered Cisco.com users (Cisco direct customers) can order a Cisco Documentation DVD (product
number DOC-DOCDVD=) from the Ordering tool or Cisco Marketplace.
Cisco Ordering tool:
http://www.cisco.com/en/US/partner/ordering/
Cisco Marketplace:
http://www.cisco.com/go/marketplace/
Ordering Documentation
You can find instructions for ordering documentation at this URL:
http://www.cisco.com/univercd/cc/td/doc/es_inpck/pdi.htm
You can order Cisco documentation in these ways:
•Registered Cisco.com users (Cisco direct customers) can order Cisco product documentation from
the Ordering tool:
http://www.cisco.com/en/US/partner/ordering/
•Nonregistered Cisco.com users can order documentation through a local account representative by
calling Cisco Systems Corporate Headquarters (California, USA) at 408 526-7208 or, elsewhere in
North America, by calling 1 800 553-NETS (6387).
Documentation Feedback
You can send comments about technical documentation to bu[email protected].
You can submit comments by using the response card (if present) behind the front cover of your
document or by writing to the following address:
Cisco Systems
Attn: Customer Document Ordering
170 West Tasman Drive
San Jose, CA 95134-9883
We appreciate your comments.

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Cisco Product Security Overview
Cisco Product Security Overview
Cisco provides a free online Security Vulnerability Policy portal at this URL:
http://www.cisco.com/en/US/products/products_security_vulnerability_policy.html
From this site, you can perform these tasks:
•Report security vulnerabilities in Cisco products.
•Obtain assistance with security incidents that involve Cisco products.
•Register to receive security information from Cisco.
A current list of security advisories and notices for Cisco products is available at this URL:
http://www.cisco.com/go/psirt
If you prefer to see advisories and notices as they are updated in real time, you can access a Product
Security Incident Response Team Really Simple Syndication (PSIRT RSS) feed from this URL:
http://www.cisco.com/en/US/products/products_psirt_rss_feed.html
Reporting Security Problems in Cisco Products
Cisco is committed to delivering secure products. We test our products internally before we release them,
and we strive to correct all vulnerabilities quickly. If you think that you might have identified a
vulnerability in a Cisco product, contact PSIRT:
•Emergencies—[email protected]m
•Nonemergencies— [email protected]
Tip We encourage you to use Pretty Good Privacy (PGP) or a compatible product to encrypt any sensitive
information that you send to Cisco. PSIRT can work from encrypted information that is compatible with
PGP versions 2.xthrough 8.x.
Never use a revoked or an expired encryption key. The correct public key to use in your correspondence
with PSIRT is the one that has the most recent creation date in this public key server list:
http://pgp.mit.edu:11371/pks/lookup?search=psirt%40cisco.com&op=index&exact=on
In an emergency, you can also reach PSIRT by telephone:
•1 877 228-7302
•1 408 525-6532
Obtaining Technical Assistance
For all customers, partners, resellers, and distributors who hold valid Cisco service contracts, Cisco
Technical Support provides 24-hour-a-day, award-winning technical assistance. The Cisco Technical
Support Website on Cisco.com features extensive online support resources. In addition, Cisco Technical
Assistance Center (TAC) engineers provide telephone support. If you do not hold a valid Cisco service
contract, contact your reseller.