Often
it is necessary to run the L band signals that are received at the dish via
the LNB through long length of cable. Compensating for cable losses can be
expensive not only in terms of amplification amplifiers but more importantly
in terms of degraded signal performance.
For that reason it is
absolutely vital that you project your DiSEqC switches and or multi switches
for maximum performance and maximum signal level out of the dish LNB
configuration,.
Use only one dish per
satellite and never use a multi block set up as this is always a physical
compromise which will result in a lower signal level and a poorer C/N ratio
from each position. Always use a dish size as large as possible. Quite simply
the signal level gained here is basically free compared to what you may
require to amplify later.
The only limit here is to
watch the maximum signal level at the input stage of any multi switch or
amplifier or Set top box. As all these units have a maximum input level
specifically with multi switches because they have an active out put stage,
you must be very careful not to overload these units.
Don’t use a smaller dish
simply to reduce signal levels but use an attenuator. The higher signal level
may be required down the distribution network and this higher lever should not
be thrown away lightly.
All satellite receivers
have a minimum and a maximum signal level. Usually between 44dbu and 80 dbu.
some STBs will work around +84dbu.
The new models of STBs now
on the market have a low threshold tuner so be careful not to over load the
front end of these. Typically any level over 80db will probably cause a signal
level to indicate but no quality or BER as on a SKY decoder.
