Desense
A very common problem in radio systems is where a
number of systems are located in close proximity to each other. Due to
little or no front-end filtering the radio signal can be predominant
within the receiver and suppresses the wanted signal from getting
through. Sometimes this situation causes other problems which reduce the
sensitivity of the radio receiver. This leads to data throughput far
below the rate expected.
Desense problems can be reduced through the use of
narrow-band front end filters to reduce the effects of the adjacent
transmission. Up to 20 dB of isolation can be achieved on 7 MHz channels
at 10.5 GHz.
Antenna Decoupling
In many situations multiple antennas are mounted on
the same antenna mast. It is assumed that the different antennas are
isolated from each other by polarisation and frequency band.
The reality of the situation is quite different and
large amounts of signal are often present at the adjacent antenna. Up to
30 dB of decoupling may be possible with two orthogonal waveguide-based
antennas however in other orientations this is rarely achieved.
Billboard Reflectors
Radio Signals can be bounced off a large flat
surface in order to reach places not possible from the transmission
source. The area of the 'billboard' is determined by the frequency and
the path length of the radio link. Quite often billboard reflectors are
used to connect two places that cannot electrically see each other. |
