Table Of Contents
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:
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:
The Warranties and License Agreements page appears.
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.
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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:
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
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
The following table lists the technical specifications for the 23.7786.51 antenna.
Operating frequency range
2400 to 2500 MHz
Maximum VSWR1 bandwidth
Azimuth plane beamwidth
Elevation plane 3 dB beamwidth (H-plane)
Elevation plane 3 dB beamwidth (E-plane)
6.4 x 0.5 in. (162 x 13 mm)
0.1 lb (0.05 kg)
1 VSWR = voltage standing wave ratio
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
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
The 23.7786.51 antenna requires a Cisco 802.11b/g radio product that uses an RP-TNC connector.
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.
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.
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.
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