WI-Fi antenna and signal boosters

1. ANTENNA GUIDE
This Antenna Guide defines four typical devices that are used to extend or enhance the range of wireless
(WiFi) Internet devices. The GUIDELINES TO HELP MAXIMIZE WIRELESS SIGNAL RANGE below apply
equally to any of the four types of devices. Also note - these devices are typically used as an enhancement to
a wireless router or access point to help increase its effective signal range.
Range Extender Antennas for a Wireless (WiFi) Router will boost the effective range of a wireless connection, from
virtually anywhere within its operating range. Specially shaped and standard pole type antennas can be used to increase
the range of Wi-Fi transmission/reception without a drastic increase in transmission power. High gain directional antennas
may be of many designs, but all allow transmitting a narrow signal beam over distances of up to several miles or
kilometers, in many cases nulling out nearby interference sources.
Broadband Amplifiers (or powered signal boosters) will allow you to increase the effective coverage of your wireless
network. The combination of a standard Wireless Router or Access Point and a Wireless (WiFi) Signal Booster device
significantly improves the system performance over the Wireless Router or Access Point alone. Typically the signal
booster is connected to the antenna output of the wireless router/access point. The signal booster which either has an
antenna of its own or uses either the antenna from the router or another replacement antenna amplifies the signal from
the router/access point and increases the signal strength. But, all the factors detailed below regarding placement, building
construction and the outdoor environment still affect the wireless (WiFi) signal.
Wireless Range Extender is a device placed between your wireless router and the dead spot in your home or office,
which you want to cover with the wireless signal. It is designed to receive and repeat signals into hard-to-reach areas of
your home or office. It performs this task without being hard wired into your network. Eliminating the need to run cables
lets you build a wireless network in a most cost effective way.
Outdoor Wireless Access Point/Client Bridge is used to create a Hotspot and extend the wireless network range.
These devices can usually be used as a Wireless Access Point (to send the signal to other locations) or a Bridge (to
receive the signal from your access point or other wireless internet sources) or a Repeater (to receive the wireless signal
and resend (repeat) it to allow longer distances or larger wireless networks). Most of these devices have built-in antennas
and also have adjustable output power facilities. And most use Power-over-Ethernet (PoE) to meet the need for cable
distance (maximum 300 feet) from the inside of a building to the device installed outside. They are housed in
weatherproof enclosures and offer a cost-effective solution for a Hotspot to create Point-to-Point and Point to Multi-Point
solutions. Because of their advanced technical nature, you should have a good working knowledge and experience in
network setup before you attempt to make changes and setup such a unit. If not you should seek the assistance of an
experienced network consultant.
BUILDING CONSTRUCTION AND PLACEMENT AFFECT THE SIGNAL
You must keep in mind that the number, thickness and location of walls, ceilings, trees and other objects that the wireless
signal must pass through, may limit the range. When you use an antenna in an outdoor setting, obstacles are among the
biggest problems when setting up for longer-range Wi-Fi signal transmission. Trees and forests degrade the signal, and
rolling hills make it difficult to establish line-of-sight propagation. In a city, buildings and poles will impact integrity, speed
and connectivity. Steel frames of buildings partly reflect radio signals, and concrete or plaster walls absorb wireless
signals significantly, but sheet metal in walls or roofs of buildings and recreational vehicles (RVs) may efficiently reflect
WiFi signals, causing an almost total loss of signal. In fact it is almost impossible for one to receive or transmit a WiFi
signal into or out of an RV without an external antenna attached to the wireless card in the computer. A laptop may
require an external antenna which is usually attached to a USB Wireless Internet Adapter.
GUIDELINES TO HELP MAXIMIZE WIRELESS SIGNAL RANGE
Typical ranges vary depending on the types of materials and background Radio Frequency noise in your home or
business. The antenna that is supplied with a wireless router usually has a minimal 3 dBi rating. The key to maximizing
wireless range is to follow a few basic guidelines:
1. Keep the number of walls and ceilings between the wireless device and other network devices to a minimum-each wall
or ceiling can reduce the wireless device's range from 3-90 feet. Position your devices so that the number of walls or
ceilings is minimized.
2. Be aware of appliances or large objects such as refrigerators or washer/dryer units that may be on the opposite side of
a wall from where you decide to place your wireless device or range extender antenna.
3. Be aware of the direct line distance between network devices. A wall that is 1.5 feet thick, at a 45-degree angle appears
to be almost 3 feet thick. At a 2-degree angle it looks over 42 feet thick! For better reception, position devices so that the
signal will travel straight through a wall or ceiling (instead of at an angle).
Antenna Guide V4.0 © 2011 Senior Computer Services – Your Technology Place – www.YourTechPlace.com
Email: info@yourtechplace.com
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2. 4. Place your wireless device on top of a desk, bookcase, or mount on a ceiling or wall away from metal cabinets and
computer cases.
5. Metallic based UV window tint or similar plastic sheeting can affect wireless performance. Do not place any wireless
device next to a tinted window.
6. Building materials can impede the wireless signal - a solid metal door or aluminum studs may have a negative effect on
range as will walls and floors made of reinforced concrete. Try to position wireless devices and computers with wireless
adapters so that the signal passes through drywall or open doorways and not other materials.
7. Recreational Vehicles (RVs) act as major reflectors of the WiFi signal. The only way to both receive and transmit the
signal when you operate a computer in an RV is to use an outdoor antenna on the roof of the RV.
8. Here is a more technical explanation about how trees affect the WiFi signal:
The average resonance frequency of water is very close to 2.4-2.5Ghz (the Wi-Fi signal operates at this frequency). Thus,
when the wireless signal passes through tree leaves (they contain water), the signal is scattered and absorbed by the
water molecules and thus you have more signal loss than other signals at other frequencies.
9. Keep your wireless router at least 3-6 feet away from electrical devices or appliances that generate RF noise.
Remember that most wireless telephone systems used in your home also operate in the 2.4GHz band.
10. You should keep the cable that connects your wireless router to an external antenna as short as possible. This is
because the longer the cable, the greater the loss of signal power. A cable length of 40 feet has a typical signal loss of
3dBi (with low-loss LMR400 cable). This loss can triple with thinner antenna cable. You should not use cables longer than
40 feet.
11. If the wireless router has more than one antenna, you can't expect an improved signal with two different antennas. If
you have more than one antenna on your wireless router you should consider replacing all of them at the same time to
keep your system balanced.
12. Assuming that you have only one antenna, it should be placed high in your room with the antenna's flat side (if it has a
flat side) facing toward the receiving computer(s).
13. You should try to place your wireless device in the center of your coverage area. In the real world, it may not be
possible to place the wireless device in the center of the required coverage area. In cases where you may experience
difficulty covering the entire area you want, try placing the device as high as possible. Wireless devices work best in lineof-sight situations where there are no obstacles between the wireless computer and the wireless device (router, access
point, extender antenna, etc.). Most wireless devices may also be mounted to a wall with the antennas facing up.
14. The wireless signal can be affected by many other things including neighboring wireless networks, microwave ovens
in operation, and 2.4GHz cordless phones. While these things can affect your wireless network performance, your
wireless network typically will work fine under most conditions where these devices exist.
15. Most Range Expander antennas have RP-SMA connectors or cables that have RP-SMA connectors at the end
that attaches to the wireless device. If you can easily unscrew the antenna(s) from your current router and the
connector on the router looks like the connector in the photo on the left below you most likely have an RP-SMA connector.
If you can unscrew the antenna but you determine that the connector is not an RP-SMA connector and it looks like the
connector in the photo in the middle below you most likely have an RP-TNC connector (note - many Linksys and Cisco
Wireless Routers have RP-TNC connectors) and you will require an adapter (as shown in the picture on the right below)
that converts the connector you have to allow you to use an antenna or an antenna cable with an RP-SMA connector. If
you can not easily unscrew your antenna and remove it from the router, then you can't use an external antenna.
If you can’t see the photos below, use the following links to see them on our website:
RP-SMA & RP-TNC Connectors and RP-TNC to RP-SMA adapter: http://www.seniorcomputers.com/images/connectors3.jpg
Antenna Guide V4.0 © 2011 Senior Computer Services – Your Technology Place – www.YourTechPlace.com
Email: info@yourtechplace.com
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