Installation Manual

Tsunami MP.11a Antenna Installation Guide
Notes:
▪ The RSL must be higher than the Receiver Sensitivity plus the minimum SNR for a good link. See Table
3 on page 23, to have a working link with no excessive errors. The amount of Fade Margin indicates the
reliability of the link; the more Fade Margin, the more reliable the link.
▪ The path loss must be smaller than the link budget minus the minimum required fade margin. The
maximum ranges cause the path loss plus the fade margin to be the same as the link budget.
The results of this link budget calculation are very important for determining any potential problems during
installation. If you have calculated the expected RSL, you can verify that it has been achieved during
installation and troubleshooting, if necessary.
In the USA and Canada, this model radio can be installed with any gain directional antennas, as there is no
Effective Isotropic Radiated Power (EIRP) limit for the application of these systems for fixed point-to-point
applications. In other countries, EIRP limits may apply.
In the case of EIRP limits, use the lesser of either (P
out
- L
1
+ G
1
) or the EIRP limit within the previous
equation. You should check this equation in both directions to assure legal application.
An EIRP limit is the maximum RF energy that can be transmitted, as measured at the transmitting antenna,
and is usually determined by government regulations.
Table 2. Receiver Sensitivity and Minimum SNR for a Good Link
Normal Mode
(Mbps)
Receiver
Sensitivity
Minimum SNR for
a Good Link
Turbo Mode*
(Mbps)
Receiver
Sensitivity
Minimum SNR for
a Good Link
54 - 69 dBm 21 108 - 66 dBm 21
48 - 73 dBm 20 96 - 70 dBm 20
36 - 77 dBm 16 72 - 74 dBm 16
24 - 81 dBm 12 48 - 78 dBm 12
18 - 84 dBm 9 36 - 81 dBm 9
12 - 86 dBm 7 24 - 83 dBm 7
9 - 87 dBm 5 18 - 84 dBm 5
6 - 88 dBm 4 12 - 85 dBm 4
* allowed in FCC regulatory domain only
The first Fresnel zone size is a list; Proxim’s recommendation is to keep at least 60-70% of this zone free. If
the clearance is lower than this percentage, the link budget and achieved fade margin are affected.
Clearances more than 100% of the Fresnel zone can cause reflections that are 180 degrees out of phase
and can cancel out the signal. The Fresnel zone works in both the horizontal and vertical paths.
Chapter 2. Determining Range and Clearance 22
CPN 65756 Issue Date: 01 August 2003