Информационное Руководство для Cisco Cisco WT2750 Multipoint Broadband Wireless System
Is either one (or both) pointed at the other system antenna(s)?
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Can you relocate and/or re−point one (or both) of your antennas to get the other
system farther away from your path axis?
system farther away from your path axis?
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Change the polarization of your antennas to be opposite (crossed) to the polarization of the
interfering system in order to solve the problem. You must first ensure that your systems
antennas are cross−polarized to the other systems antennas, because this solution is so
effective and requires the least cost and effort to implement.
interfering system in order to solve the problem. You must first ensure that your systems
antennas are cross−polarized to the other systems antennas, because this solution is so
effective and requires the least cost and effort to implement.
If the problem persists, change the frequency of one of the systems (probably your own).
Systems that are not on (or close to being on) the same frequency rarely interfere with each
other. If the interferer is very high−powered (such as radar), interference can still occur
because the powerful interferer overloads the receiver, and causes interference−like
symptoms. Change of frequencies is usually effective.
Systems that are not on (or close to being on) the same frequency rarely interfere with each
other. If the interferer is very high−powered (such as radar), interference can still occur
because the powerful interferer overloads the receiver, and causes interference−like
symptoms. Change of frequencies is usually effective.
Note: This solution is only appropriate in the case of systems that operate in unlicensed
bands, where the use of a specific frequency is not necessary. This solution option is typically
not available to licensed users, although such users are not likely to encounter interference
that they can solve this way.
bands, where the use of a specific frequency is not necessary. This solution option is typically
not available to licensed users, although such users are not likely to encounter interference
that they can solve this way.
Sometimes, you need to change frequencies for both your system and the interfering system,
in order to maximize the frequency separation.
in order to maximize the frequency separation.
In order to change the frequency of your system, swap the transmit and receive frequencies.
This process requires removal and reinstallation of both of your duplexers, in order to turn
them around to accommodate the now−reversed TX/RX frequency split. You do not need to
make any other adjustment or re−alignment of the antennas. You can try this when you
experience interference at only one end of your link (the most common situation), because the
link end where the receiver was receiving interference now transmits on that frequency. In
other words, only receivers can experience interference!
This process requires removal and reinstallation of both of your duplexers, in order to turn
them around to accommodate the now−reversed TX/RX frequency split. You do not need to
make any other adjustment or re−alignment of the antennas. You can try this when you
experience interference at only one end of your link (the most common situation), because the
link end where the receiver was receiving interference now transmits on that frequency. In
other words, only receivers can experience interference!
You must use the final tool to alleviate an interference problem only after you have
unsuccessfully tried all the others. That tool is antenna gain. For antennas, higher gain is
virtually synonymous with narrower beamwidth. When you change antennas to higher−gain,
lower−beamwidth types your system becomes less able to see the interferer, and this step
sometimes solves the problem.
unsuccessfully tried all the others. That tool is antenna gain. For antennas, higher gain is
virtually synonymous with narrower beamwidth. When you change antennas to higher−gain,
lower−beamwidth types your system becomes less able to see the interferer, and this step
sometimes solves the problem.
Note: Usually only one end of a link experiences interference. Therefore, you only need to
change the antenna at the link end where the receiver experiences the problem. Changing
antennas is the most costly and time−consuming solution. Therefore, install antennas of
adequate gain (narrow enough beamwidth).
change the antenna at the link end where the receiver experiences the problem. Changing
antennas is the most costly and time−consuming solution. Therefore, install antennas of
adequate gain (narrow enough beamwidth).
If you decide to replace one or both antennas with higher gain units, verify that the TX power
needs to be adjusted downward to ensure that the radiated TX power (EIRP) still complies
with the applicable FCC rules.
needs to be adjusted downward to ensure that the radiated TX power (EIRP) still complies
with the applicable FCC rules.
Q. Can you give a short troubleshooting checklist for a point−to−point
link?
link?
Are the antennas both polarized properly (the same as each other)?
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Are the antennas aligned properly?
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Is the DC power set for the correct voltage, turned on, and properly connected to
PFPs?
PFPs?
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Are there any bullet holes in any of the outdoor components?
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