Motorola PTP 400 Series - Manual (Page 23)

21
Peak power density in the far field of a radio frequency point source is calculated as follows:
Rearranging terms to solve for distance yields
S
G P
d
π
4
⋅ =
(Note: Allowance should be made for any TDD structure employed)
2.1.1.1 Calculated Distances and Power Compliance Margins
Table 3 shows calculated minimum separation distances d, recommended distances and
resulting power compliance margins for each frequency band and antenna combination.
Variable
Band Antenna
Max RMS
Power in
Burst (Watt)
P
(Watt)
G S
(W/m 2 )
D 1
(m)
Recom-
mended
Distance
(m)
Power
Compli
ance
Margin
Integrated 0.2 (23dBm) 0.1
158
(22dBi)
10 0.35 3 8.5
4.9 GHz
External
(max EIRP)
0.2 (23dBm) 0.1
398
(26dBi)
10 0.56 5 8.9
5.4 Ghz Integrated 0.0025(4dBm) 0.0013
200
(23dBi)
10 0.04 1 22.4
Integrated 0.32 (25dBm) 0.16
200
(23dBi)
10 0.50 2 4.0
External 2ft
Flat Plate
0.32 (25dBm) 0.16
631
(28dBi)
10 0.90 4 4.5 5.7 GHz
External 6ft
Dish
0.32 (25dBm) 0.16
6310
(38dbI)
10 2.83 10 3.5
1. Calculated
Table 3 - Power Compliance Margins
Notes:
1. The regulations cover the power averaged over a 6 minute period.
2. At 5.4GHz the product is generally to a fixed EIRP which can be achieved with the
Integrated Antenna. If there are no EIRP limits, use the distance calculations for 5.7GHz.
3. At 5.7GHz, for antennas between 2ft and 6ft, alter the distance proportionally to the
antenna gain.