MBF-40 SMR900 PS REPEATER
PRODUCT DESCRIPTION AND USER’S MANUAL
Cobham Wireless
–
Coverage
Date: 31-May-18
www.cobham.com/wireless
Doc. No. 00141UM
Rev. 1.0
Page |
VI
FCC RF Exposure Limits
This unit complies with FCC RF exposure limits for an uncontrolled environment. This equipment must be installed and
operated with a minimum distance of 33 cm between the radiator and any person’s body.
Antenna Installation
Installation of an antenna must comply with the FCC RF exposure requirements. The antenna used for this booster must
be mounted on a permanent structure.
The FCC regulations mandate that the ERP of type B signal boosters should not exceed 5 W, this is equivalent to 8.2 W
EIRP.
Therefore the max antenna gain allowed for this type of signal booster should be limited to the values given by equation
1 (below) for the service antenna.
Equation (1) — Max SERVICE antenna gain
Maximum service antenna gain (dBi) = 39.1 – (37 dBm - # of antennas in dB – cable losses in dB).
For example:
No. of Antennas
Cable Losses
Max Allowed Antenna Gain
4
3
39.1 - (37-6-3) =11.1dBi
1
3
39.1- (37-0-3) = 5.1dbi
10
3
39.1- (37-10-3) = 15.1dbi
Compliance with FCC deployment rule regarding the radiation of noise and intermodulation
product
Good engineering practice must be used in regard to the signal booster’s radiation of intermodulation products and
noise. Thus, the gain of the signal booster should be set so that the ERP of the output of intermodulation products from
the signal booster should not exceed the level of -30 dBm in 10 kHz measurement bandwidth and noise from the signal
booster should not exceed the level of -43 dBm in 10 kHz measurement bandwidth.
In the event that the intermodulation or noise level measured exceeds the aforementioned values, the signal booster
gain should be decreased accordingly.
In general, the ERP of noise on a spectrum more than 1 MHz outside of the pass band should not exceed -70 dBm in a
10 kHz measurement bandwidth.
The MBF-900 repeater has a noise level of -43.8 dBm in 10 kHz measurement at 1 MHz spectrum outside the passband
of the signal booster, worst case intermodulation products at around -14.9 dBm in a 10 kHz bandwidth and an in-band
noise level at around -42.8 dBm in a 10 kHz bandwidth. Therefore, the noise or intermodulation product at the antenna
input port should be calculated based on equation (2).
Equation (2) — Input Noise or intermodulation product to service antenna
Input Noise to service antenna:
-XX dBm + Service Antenna gain – antenna splitter losses in dB – cable loss in dB
Example: Intermodulation product
Signal booster connected to 10 service antennas with a 100m long ½ inch cable.
Losses of such a cable with the connectors = ~ 12dB
Assuming 10 service antennas: antenna splitter losses = 11 dB
Based on equation (2) Input antenna noise (to the antenna) = -14.9-12 -11= -37.9 dBm ERP
The intermodulation product to the antenna should be -14.9 -12-11= -37.9dbm ERP
Summary of Contents for MBF-40 Americas
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