TELE-audiovision - The World’s Largest Digital TV Trade Magazine - page 70

TELE-audiovision International — The World‘s Largest Digital TV Trade Magazine
— 07-08/2013
One Cable Solution for Satellite and Terrestrial
How to Feed a Twin Tuner PVR
With Only One Coax Cable
A clever way to add a
second satellite signal
to a PVR receiver
frequencies, each carrying
only one transponder sig-
nal at a time. On the other
end of the coax cable (in the
room) there are either two
single tuner receivers or two
tuners of a PVR connected
in series one after another.
The connection to the tuners
is done with the help of sub-
scriber sockets (for example
SPAUN UNiSocket).
One carrier is exclusively
assigned to one tuner only.
Each tuner sends a special
EN 50949 command to the
SCR telling it which satellite
transponder it should tune to
and repeat its signal on the
output carrier. The receiver
tuner is then tuned to this
carrier rather than to the
transponder it wants to re-
Now comes SPAUN. They
just introduced a device
called SUS 21 F, which is just
such a simple 2 input SCR
as described above. As al-
ways with SPAUN products,
the SCR workmanship leaves
nothing to be desired. SUS
21 F has very clear blue ink
descriptions on the top cover
not only explaining the func-
tion of every connector but
also providing basic param-
eters of the unit. The jack
connectors accept female
F-connectors and are 20
mm apart form one another.
Such distance make it a per-
fect match for SPAUN multi-
switches. If you use one, you
can directly snap SUS 21 F
onto the switch. If you want
to connect it to the outputs
of a TWIN LNB, you can use
two short coax cables.
Even without referring to
the manual, we can learn the
frequencies of the two car-
riers (1076 MHz and 1178
MHz), the required input sig-
nal level (65...95 dBμV) as
well as the output level that
is automatically regulated to
82 dBμV. The allowable input
level is wide and thanks to
that it is suitable to all sorts
of LNBs as well as multi-
switches. On the other hand,
the output is quite high al-
lowing you to use quite long
cables what we actually did
in our test described below.
Modern twin tuner receiv-
ers with PVR functionality
require two coax cables from
a multiple LNB or from a mul-
tiswitch to achieve full func-
tionality - one cable for each
tuner. By full functionality,
we mean recording a channel
from one transponder while
watching another one from a
different transponder. How-
ever, quite often our indoor
installation is prepared just
for a single tuner receiver:
only one coax cable enters
a room. So, do we have to
ruin our walls and ceilings
laying additional cables to
enjoy the full functionality of
our brand new receiver? Not
You have another very
convenient option if only
your receiver supports the
EN 50494 single cable pro-
tocol. Fortunately, more
and more receivers do. For
single cable installation, you
just need is a single cable
router (SCR). The simplest
form of an SCR is a two in-
puts device. It accepts two
signals from a TWIN LNB
and converts them in such
a way that both signals co-
exist in the output to which
a coax cable is connected.
Of course, the output sig-
nal differs dramatically from
the input signals. There are
only two DVB-S/S2 carriers
on the SCR output at fixed
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