A
XELL
BSF-4004
BSF0038
S
ERIES
R
EPEATER
PRODUCT DESCRIPTION AND USER’S MANUAL
Equation (3) - Input Noise to service antenna
Input Noise to service antenna:
-45 dBm + Service Antenna gain – Antenna splitter losses in dB – cable loss in dB
Example:
Signal booster connected to 20 service antennas with a 100m long ½ inch cable.
Losses of such a cable with the connectors = ~ 12dB
Gain = ~ 2 dBi
Assuming 20 service antennas: antenna splitter losses = 15 dB
Based on equation (3) Input antenna noise (to the antenna) = -45+2-12 -15=-70 dBm
The inband input noise to the antenna should be -45+2 -12-15= -70dbm
NOTE: In this example there is no need to add an external band pass filter to attenuate the out of
band noise. If fewer antennas are deployed then additional filtering may be required
Conclusion:
Good engineering practice requires that in general when the out of band noise measured at the
service antenna input is more than -70 dBm per 10 kHz measurement bandwidth, an external band
pass filter should be added to attenuate the out of band noise level.
All Axell Wireless repeaters include high selectivity duplexers and filters to attenuate the out of band
noise. Should additional filtering be required, we have a comprehensive range of interference filters
which can be supplied upon request.
VI
Doc. No. PN 4004 BSF0038 Series-UM Rev. 1.0
© Axell Wireless Ltd
