Druckschrift 9981.0190, Broadcast Antenna Systems - Romkatel
Druckschrift 9981.0190, Broadcast Antenna Systems - Romkatel
Druckschrift 9981.0190, Broadcast Antenna Systems - Romkatel
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dB<br />
Relay Receiving <strong>Antenna</strong>s for<br />
TV and FM <strong>Broadcast</strong>ing<br />
Receiving antenna systems with high side-lobe<br />
suppression and notches for the suppression<br />
of interference can significantly improve the<br />
signal quality of the relay receiving systems.<br />
Due to ever-increasing transmitter density, relay<br />
receiving systems can suffer difficulties due to<br />
co-channel or adjacent channel interference. In<br />
mountainous regions additional interference may be<br />
caused by reflected signals that arrive delayed.<br />
In order to suppress such interference, several<br />
individual antennas can be combined. Optimization of<br />
both the mechanical array and the electrical feeder<br />
system results in notches in the direction of the<br />
disturbance. Array patterns with notches in two different<br />
directions can also be produced to suppress interference<br />
coming from a variety of sources.<br />
To solve interference problems Kathrein offers<br />
receiving antennas with high side-lobe suppression<br />
for all frequency ranges.<br />
16°<br />
10<br />
3<br />
0<br />
Horizontal radiation pattern<br />
Half-power beam width: 16°<br />
Side-lobe suppression: > 30 dB<br />
If high quality individual antennas are used, array<br />
patterns with particularly high side-lobe suppression can<br />
be produced.<br />
Kathrein’s log.-per. antennas have been specially<br />
developed for such purposes. For example over the whole<br />
TV Band III range they achieve a side-lobe suppression<br />
value of more than 25 dB in both the horizontal and the<br />
vertical patterns. A further advantage of our log.-per.<br />
antennas is that their excellent radiation characteristics<br />
are hardly affected at all by very heavy ice formation.<br />
The following examples show measured radiation<br />
patterns of antenna arrays for all VHF and TV transmitting<br />
ranges (the side-lobes were enlarged by a<br />
factor of 10 to ease identification).<br />
Examples for Horizontal Radiation Patterns<br />
47 … 88 MHz 87.5 – 108 MHz 174 – 230 MHz<br />
470 – 860 MHz<br />
10 dB expanded<br />
10 dB expanded<br />
10 dB expanded<br />
10 dB expanded<br />
10<br />
10<br />
10<br />
10<br />
3<br />
dB<br />
3<br />
dB<br />
3<br />
dB<br />
3<br />
dB<br />
0<br />
3 units K 52 16 8..<br />
0<br />
2 units K 52 22 1..<br />
0<br />
3 units K 52 22 5.. 4 units K 72 23 4..<br />
0<br />
52
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