The wireless calculator is for outdoor wireless deployment reference only and contains the following
functions:
| Wi-Fi Link Budget Calculation |
the reference of WLAN Backbone System or WLAN Surveillance System (PtP link) |
| Fresnel Zone Calculation |
the reference of WLAN Backbone System or WLAN Surveillance System (PtP link) |
| Antenna Downtilt Calculation |
the reference of WLAN Internet Surfing Coverage System. |
| Downtilt Coverage Calculation |
the reference of WLAN Internet Surfing Coverage System. |
The calculated results provided are based on the assumption of radio Line-of-Sight (LoS) and thus it only
takes into account the free space path loss and cable loss based on your input values. If you have a long
radio link, you will need to take all effects (e.g. earth's curvature, refractive index, and more) into
account. The final value represents a first order approximation and should only be used as a guide. No
guarantees or warranties are implied accordingly.
Note:
The Line-of-Sight (LoS) between radios is required and at
least 80% clear of any obstruction in the Fresnel Zone is recommended.
The path between two antennas is referred to as the Line-of-Sight (LoS).
The Fresnel Zone referenced
in the diagrams below is an electromagnetic phenomenon, where radio signals get diffracted or bent from
solid objects near their path.
There are three main categories of Line of Sight for reference:
- Line of Sight (LoS): No obstacles reside between the two antennas; the link can be established and is
reliable.
- Near Line of Sight (nLoS): Partial obstructions such as tree tops between the two antennas are
included. The link may be established with lower performance, but may not be stable.
- Non Line of Sight (NLoS): Where full obstructions exist between the two antennas, the link is
difficult to establish.
Description:
The Wi-Fi Link Budget is a way of quantifying a
communication link's performance while accounting for the system's power, gains, and losses for both the
transmitter (Tx) and receiver (Rx).
The Free Space Loss is the transmission loss between two antennas,
separated by a distance.
The System Operating Margin is a measure in dB of the signal loss your system
can withstand before it degrades to the error rate specified at your Receiver Sensitivity threshold.
Note:
- The following Rx Signal Level is recommended:
- For WLAN Backbone System: -50dBm ~ -30dBm
- For WLAN Surveillance System: -55dBm ~ -35dBm
- For WLAN Internet Surfing Coverage System: -60dBm ~ -40dBm
- A minimum 20 dB System Operating Margin is recommended for a reliable link.
- Considering the winds to the offset of the antenna, ground shaking (e.g. windmills, wind
generators and etc), air temperature and humidity changes (e.g. rain, haze, dust), the link distance
over 25miles or 40km are very difficult to align and install.
- The Maximum Transmission Distance provided is based on theory and only for design reference. For
actual values, field trial is required.
The estimated distance shown in the table is generated based on the above input values of both sites.
| Data Rate |
Estimated Distance |
| 1 Mbps (802.11b) |
1.939 miles (3.121 Km) |
| 2 Mbps (802.11b) |
1.939 miles (3.121 Km) |
| 5.5 Mbps (802.11b) |
1.540 miles (2.479 Km) |
| 11 Mbps (802.11b) |
1.540 miles (2.479 Km) |
| 6 Mbps (802.11g) |
1.939 miles (3.121 Km) |
| 9 Mbps (802.11g) |
1.540 miles (2.479 Km) |
| 12 Mbps (802.11g) |
1.540 miles (2.479 Km) |
| 18 Mbps (802.11g) |
1.540 miles (2.479 Km) |
| 24 Mbps (802.11g) |
1.373 miles (2.209 Km) |
| 36 Mbps (802.11g) |
0.345 miles (0.555 Km) |
| 48 Mbps (802.11g) |
0.244 miles (0.393 Km) |
| 54 Mbps (802.11g) |
0.194 miles (0.312 Km) |
| 15 Mbps (802.11n/HT40-MCS0) |
1.939 miles (3.121 Km) |
| 30 Mbps (802.11n/HT40-MCS1) |
1.540 miles (2.479 Km) |
| 45 Mbps (802.11n/HT40-MCS2) |
1.373 miles (2.209 Km) |
| 60 Mbps (802.11n/HT40-MCS3) |
1.090 miles (1.755 Km) |
| 90 Mbps (802.11n/HT40-MCS4) |
0.688 miles (1.107 Km) |
| 120 Mbps (802.11n/HT40-MCS5) |
0.487 miles (0.784 Km) |
| 135 Mbps (802.11n/HT40-MCS6) |
0.218 miles (0.350 Km) |
| 150 Mbps (802.11n/HT40-MCS7) |
0.154 miles (0.248 Km) |
| 180 Mbps (802.11n/HT40-MCS12) |
0.688 miles (1.107 Km) |
| 240 Mbps (802.11n/HT40-MCS13) |
0.487 miles (0.784 Km) |
| 270 Mbps (802.11n/HT40-MCS14) |
0.218 miles (0.350 Km) |
| 300 Mbps (802.11n/HT40-MCS15) |
0.154 miles (0.248 Km) |
Description:
The radio frequency line of sight is defined by
Fresnel Zones which are ellipse-shaped areas between any two radios. The primary Fresnel zone is required
to be at least 80% clear of any obstruction to ensure the highest performance of wireless link.
Note:
The final value represents a first order approximation and
should only be used as a guide. No guarantees or warranties are implied accordingly.
Description:
The Antenna Downtilt is used to determine the
approximate downward angle, measured in degrees, which the transmitting antenna is to be positioned for
optimal signal strength and coverage.
Note:
The final value represents a first order approximation and
should only be used as a guide. No guarantees or warranties are implied accordingly.
Description:
Besides the Antenna Downtilt, the Downtilt Coverage
Calculator will also give you the inner and outer radius of coverage given the antenna's
beamwidth.
Inner Cell Radius: When clients in this area are difficult to connect to the AP
Outer
Cell Radius: The maximum antenna radius coverage
Vertical Beamwidth: The perpendicular to the ground as
to antenna orientation.
Note:
- The final value represents a first order approximation and should only be used as a guide. No
guarantees or warranties are implied accordingly.
- Outer Radius Distance: The value should be “positive”; the "negative" value means the radiation lobe
does not touch the ground.
