User's Manual

Section 2 Microwave Path Engineering Basics TRACER 6000 Series Integrated System Manual
20 Copyright © 2005 ADTRAN, Inc. 612806420L1-1D
Transmitted Power (P
T
)
The FCC specifies the maximum transmitter power used for antennae of a given gain. FCC Rules Part 15,
Subpart 247 allow for a maximum power of 1 watt (30 dBm) into antennae of a gain less than or equal to
6 dBi. At 2.4 GHz (TRACER 6410), the 1-watt maximum transmitter power must be reduced by 1 dB for
every 3 dB of antenna gain over 6 dBi. This rule is shown in Table 5 (for information only).
For the 5.8 GHz band (TRACER 6420), the maximum output power is 1 watt (30 dBm) regardless of the gain
of the attached antenna. Since the TRACER 6420 maximum transmit power is 100 milliwatts, there is
reduction in transmitter output power required.
Carrier Wavelength (λ)
The carrier wavelength is the physical wavelength of the main RF carrier being used for communication, and
is usually approximated at the center frequency of the band (which is 2421.7 MHz for TRACER 6410 and
5787.5 MHz for the TRACER 6420). The carrier wavelength calculations follow.
λ = c / f (meters)
where
c = speed of light (in meters)
f = frequency (in Hz)
resulting in the following carrier wavelengths
TRACER 6410
λ = 3.00 x 10
8
/ 2421.7 x 10
6
= 0.124 m or 12.4 cm
= 4.88 in
Table 5. Transmit Power Reduction for Various Antennae Gains
Output Power
(dBm)
Maximum
Antenna Gain
(dBi)
Maximum EIRP
(dBm)
30 6 36
29 9 38
28 12 40
27 15 42
26 18 44
25 21 46
24 24 48
23 27 50
22 30 52
21 33 54
20 36 56
The TRACER 6410 is only approved to operate with dish antennas with a maximum gain of 21.1dBi.
TRACER 6420
λ = 3.00 x 10
8
/ 5787.5 x 10
6
= 0.0518 m or 5.18 cm
= 2.04 in