TechniSat GigaSystem 17/8 K - Handbuch (Seite 33)

Terrestrial reception
> The simplest solution is to use a terrestrial broadband antenna. In this case you must
pay particular attention that the FM signals are not too strong.
> If the signals of the various bands are received from different directions, it is recom-
mend you use several antennae, connected by a terrestrial combiner (filter). To some
extent, different signal strengths can be compensated by using different antenna
sizes.
The signal path is designed to be fairly resistant against any intermodulation (output levels at
60 dB IMA3: 102 dBμV, in accordance with DIN 45004 B). However, if you are simulta-
neously distributing FM, VHF or a cable signal as well as UHF, you may encounter cross
modulation interference (Moiré). In this case you should consider the following
> Use a pre-amplifier (naturally with a low noise level and resistant to overload) only
if there are no high-strength signals in the range (even if you otherwise have weak
input signals).
> Analogue TV signals of < 60 dBμV suffer from significant noise, particularly in larger
installations, and are not suitable for this type of distribution. Incoming DVB-T signals
with strength of 45 dBμV can still be distributed.
In case some of the participants are only interested in receiving a „basic“ package of
terrestrial signals, please branch off the combined terrestrial incoming signal either before it
reaches the first switching matrix, or in the middle of the cascaded distribution. If necessary,
you can insert a preamplifier at this stage (without, however, exceeding the maximum input
level possible).
If you require only a very small number of connections for this „basic package“, you can also
implement it by splitting one branch off a switching matrix (benefit: utilisation of the gain pro-
vided by the 17/X system).
5.3 Installation
> Mark each cable at both ends with the apartment and/or room number, and note the
number of the switching matrix in the socket.
> As far as possible, install the cables as single unbroken sections. Faulty F to F-
connector jacks inserted along the way can cause interference and errors.
> If you are installing very long sections of cable to the individual participants (> 60 m),
you should install a double wall socket (as open for future use) after about 3/4 of the
total length. So that you can, if necessary, open up the cable and install an interme-
diate amplifier at a later stage.
> For screw-type connectors, use socket wrench Art. No. 0000/3407. Do not over-tigh-
ten the nuts of the F-connectors.
> Do not use quick-fastening (snap-on) F-connectors.
> If you are not sure as to where a particular cable leads, fit a 75-Ohm resistor to what
you consider to be the other end, and measure the resistance.
If some participants are not to receive the satellite signals, simply insert a DC block (Art. No.
0000/3405) in their supply lines
You can also connect this participant to a another participant by means of a 2-way splitter,
that does not provide a direct current path at this point.
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