With two of those antennas a distance for data transfer can be up to 20km enable a transfer rate of 2Mbit/s. The Antenna is equipped with RP-SMA (R-SMA)male:

Fully comatible to all 2,4GHz WLAN 802.11b & 802.11g Systems, like Netgear, D-Link, Orinocco. Technical datas are approximately like Cisco Yagi Antenna, which costs over $ 300,--.

Azimuth Plane Radiation Pattern

Elevation Plane Radiation Pattern

 Technical Data:

Fequency: 2.4 GHz - 2.485 GHz VSWR: approx. 1:1.5 Beamwidth: h/v 30/30 ° Impedance: 50 Ohm/Ohms

Polarisation: Horizontal or vertikal Housing: open construction  connector: 1m RP-SMA-Male Standart: 802.11b & g Dimensions: 49 x 6,5cm

This arrestor is designed to be installed between your outdoor antenna cable and the Aironet wireless device. Installation should be indoors, or inside a protected area. A good ground must be attached to the arrestor. This can be accomplished by use of a ground lug attached to the arrestor and a heavy wire (no. 6 solid copper) connecting the lug to a good earth ground. See Figure 6. UNDERSTANDING RF POWER VALUES

Radio frequency (RF) signals are subject to various losses and gains as they pass from transmitter through cable to antenna, through air (or solid obstruction), to receiving antenna, cable, and receiving radio. With the exception of solid obstructions, most of these figures and factors are known and can be used in the design process to determine whether an RF system such as a WLAN will work.

The decibel (dB) scale is a logarithmic scale used to denote the ratio of one power value to another-for example:

dB = 10 log10 (Power A/Power B)

An increase of 3 dB indicates a doubling (2x) of power. An increase of 6 dB indicates a quadrupling (4x) of power. Conversely, a decrease of 3 dB is a halving (1/2) of power, and a decrease of 6 dB is a quarter (1/4) the power. Some examples are shown below in Table 1.

Increase	Factor	Decrease	Factor
0 dB	1 x (same)	0 dB	1 x (same)
1 dB	1.25 x	-1 dB	0.8 x
3 dB	2 x	-3 dB	0.5 x
6 dB	4 x	-6 dB	0.25 x
10 dB	10 x	-10 dB	0.10 x
12 dB	16 x	-12 dB	0.06 x
20 dB	100 x	-20 dB	0.01 x
30 dB	1000 x	-30 dB	0.001 x
40 dB	10,000 x	-40 dB	0.0001 x

dBm	mW	dBm	mW
0 dBm	1 mW	0 dBm	1 mW
1 dBm	1.25 mW	-1 dBm	0.8 mW
3 dBm	2 mW	-3 dBm	0.5 mW
6 dBm	4 mW	-6 dBm	0.25 mW
7 dBm	5 mW	-7 dBm	0.20 mW
10 dBm	10 mW	-10 dBm	0.10 mW
12 dBm	16 mW	-12 dBm	0.06 mW
13 dBm	20 mW	-13 dBm	0.05 mW
15 dBm	32 mW	-15 dBm	0.03 mW
17 dBm	50 mW	-17 dBm	0.02 mw
20 dBm	100 mW	-20 dBm	0.01 mW
30 dBm	1000 mW (1 W)	-30 dBm	0.001 mW
40 dBm	10,000 mW (10 W)	-40 dBm	0.0001 mW

The range of a wireless link is dependent upon the maximum allowable path loss. For outdoor links this is a straightforward calculation as long as there is clear line of sight between the two antennas with sufficient clearance for the Fresnel zone. For line of sight, you should be able to visibly see the remote locations antenna from the main site. (Longer distances may require the use of binoculars). There should be no obstructions between the antennas themselves. This includes trees, buildings, hills, and so on.

As the distance extends beyond six miles, the curve of the earth (commonly called earth bulge) affects installation, requiring antennas to be placed at higher elevations.