Netgear ME103 ME103 Reference Manual - Page 67

Antenna Installation

Page 67 highlights

User's Guide for the ME103 802.11b ProSafe Wireless Access Point Antenna Installation The ME103 comes with two removable 2-dBi antenna. Two antennae provides what is called "space diversity" which helps to combat the addition of electromagnetic waves in the space where the unit is installed. This effect is called "multipath fading." Multipath fading is generated by the multiple reflections of electromagnetic waves in an office due to walls, ceiling, floors, partitions, doors, metallic polls, cubicles, etc. and the motion of people and objects. The benefits of two antennae is evident when there is distance or obstructions in the line of sight between the ME103 and the clients. When only one antenna is used, a degradation of up to 50% of data throughput can be noticed in several spots of the coverage and also at the fringes of the range. The two 2dBi antenna are dipole and vertical polarization. They provide an optimal radiation pattern in the plane perpendicular to their direction. When oriented vertically, they provide a optimal range in the horizontal plane (horizontal donut shaped signals). If the office is small and on multi-floors, it is advised to put the antenna flat so that the maximum coverage is vertical rather than horizontal. When the office is odd shape it is advised to do some orientation trials. For applications requiring more range, wireless accessories can be used such as external antennae and bi-directional booster(s). The first optional update is replacing the two 2dBi antennae by two 5-7dBi dipole antennae. Simply unscrew the two antenna and screw on the new ones when the ME103 is switched off. Be sure to use antenna with a reversed SMA connector. Another solution is to relocate the antenna(e) with an RF cable to an optimal spot such as a ceiling, high on a wall, etc. One typical application is to locate the ME103 is in a secure location like a data center. Two external antenna are placed outside the room, for example on the ceiling, and connected with RF cables to the ME103. Another application is two external directional antennae, one pointing to one side of the building, and the other to the other side. Be aware of the loss in the cable. If too long and used with a medium gain antenna, it can reduce or eliminate the gain from placing the antenna in good spot. Only high gain antenna (more than 10dBi) should be used with a long cable such as 5 or 10m. To cope with this inherent limitation, NETGEAR also provides bi-directional booster. This component amplifies the RF signal in transmit mode and in receive mode. It automatically switches itself to the receive or transmit mode. The booster is placed very close to the antenna and provides an outstanding output RF power of 500mW or 27dBm. It also includes a low noise amplifier for the receive path of 10dB gain minimum. With such a booster, the antenna and booster can be connected with a cable as long as 10 to 15m from the ME103 without any performance reduction. Advanced Configuration 4-15

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User’s Guide for the ME103 802.11b ProSafe Wireless Access Point
Advanced Configuration
4-15
Antenna Installation
The ME103 comes with two removable 2-dBi antenna. Two antennae provides what is called
“space diversity” which helps to combat the addition of electromagnetic waves in the space where
the unit is installed. This effect is called “multipath fading.” Multipath fading is generated by the
multiple reflections of electromagnetic waves in an office due to walls, ceiling, floors, partitions,
doors, metallic polls, cubicles, etc. and the motion of people and objects. The benefits of two
antennae is evident when there is distance or obstructions in the line of sight between the ME103
and the clients. When only one antenna is used, a degradation of up to 50% of data throughput can
be noticed in several spots of the coverage and also at the fringes of the range.
The two 2dBi antenna are dipole and vertical polarization. They provide an optimal radiation
pattern in the plane perpendicular to their direction. When oriented vertically, they provide a
optimal range in the horizontal plane (horizontal donut shaped signals). If the office is small and
on multi-floors, it is advised to put the antenna flat so that the maximum coverage is vertical rather
than horizontal. When the office is odd shape it is advised to do some orientation trials.
For applications requiring more range, wireless accessories can be used such as external antennae
and bi-directional booster(s). The first optional update is replacing the two 2dBi antennae by two
5-7dBi dipole antennae. Simply unscrew the two antenna and screw on the new ones when the
ME103 is switched off. Be sure to use antenna with a reversed SMA connector.
Another solution is to relocate the antenna(e) with an RF cable to an optimal spot such as a ceiling,
high on a wall, etc. One typical application is to locate the ME103 is in a secure location like a data
center. Two external antenna are placed outside the room, for example on the ceiling, and
connected with RF cables to the ME103. Another application is two external directional antennae,
one pointing to one side of the building, and the other to the other side. Be aware of the loss in the
cable. If too long and used with a medium gain antenna, it can reduce or eliminate the gain from
placing the antenna in good spot. Only high gain antenna (more than 10dBi) should be used with a
long cable such as 5 or 10m.
To cope with this inherent limitation, NETGEAR also provides bi-directional booster. This
component amplifies the RF signal in transmit mode and in receive mode. It automatically
switches itself to the receive or transmit mode. The booster is placed very close to the antenna and
provides an outstanding output RF power of 500mW or 27dBm. It also includes a low noise
amplifier for the receive path of 10dB gain minimum. With such a booster, the antenna and booster
can be connected with a cable as long as 10 to 15m from the ME103 without any performance
reduction.