System characteristics
28
Planning Aastra 400 DECT systems as of R1.0
syd-0457/1.0 – R1.0 – 10.2012
Fig. 11 Example 2: Corner reflector antenna
The same principle applies to all antenna types: The narrower the horizontal and
vertical radiation range, the greater the distances that can be covered. In this con-
nection we talk of antenna gain, which indicates the ratio of the energy radiated in
a particular angle to the radiated energy of a standard antenna (usually a /2 di-
pole antenna). An extreme example of this is the radio relay antenna, which is used
for transmitting radio signals in a targeted direction from one point to the next.
Note:
When using external antennas, the cable length between radio unit and
antenna should be as short as possible because the attenuation of the
radio signals in send and receive direction is not to be neglected in this
frequency range (approx. 1.5 dB per meter for a normal cable). A 4-meter
long cable thus compensates for an antenna gain of 6 dB. It may be useful
to consider using a special low-attenuation cable.
Horizontal Vertical
Radiation pattern in relative eld strength
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