RF EXPOSURE WARNING
The antenna used for this transmitter must be fixed-mounted on outdoor permanent
structures. In order to satisfy the FCC RF exposure requirements, the BDA/antenna
installation must comply with the following:
The downlink indoor antenna (Omni type or similar directional antenna) must be installed so
as to provide a minimum separation distance of 0.35 meters (35 cm) between the antenna
and persons within the area. (This assumes a typical antenna with maximum gain of [
2
dBi,
VSWR >?> 1.5:1, Zo= 50 ohms, and a cable attenuation of between
2
-10 dB)
The uplink outdoor antenna (Yagi type or similar directional antenna) must be installed so as
to provide a minimum separation distance of 0.35 meters (35 cm) between the antenna and
persons within the area. (This assumes a typical antenna with maximum gain of [1
3
dBi,
VSWR >?> 1.5:1, Zo= 50 ohms, and a cable attenuation of between
2
-10 dB).
DIAGNOSTICS GUIDE
The BDA provides long term, care-free operation and requires no periodic maintenance.
There are no user-serviceable components inside the BDA. This section covers possible
problems that may be related to the installation or operating environment.
a. Gain Reduction
Possible causes: Bad RF cables and RF connections to antennas, damaged antennas.
b. Excessive Intermodulation or Spurious
Possible causes:
Amplifier oscillation caused by insufficient isolation. The isolation between two antennas is
given by the equation:
Isolation = 92.5 + 20 Log (F x D) – Gt – Gr
W
here:
F = frequency (GHz) Gt = transmit antenna gain (in the direction of the receive antenna)
D = separation (Km) Gr = receive antenna gain (in the direction of the transmit antenna)
For example, at the SMR frequencies, the antenna isolation at 100 m separation is about 71
dB for omni-directional antennas (0 dB gain). To increase isolation, the antennas should
have higher directivity and must be pointed away from each other.
c. Occasional Drop-out of some Channels
Possible causes: One channel with very strong power dominates the RF output of the
amplifier.
38 Leuning Street
South Hackensack, NJ 07606
Tel. 201-343-3140 Fax 201-343-6390
www.gwaverf.com
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