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TELE-satellite International — The World‘s Largest Digital TV Trade Magazine
— 04-05/2012
— www.TELE-satellite.com
refresh rate simply does not
keep up with signal changes.
If you’re done with the
spectrum a simple touch of
the ‘Menu’ button will bring
you back to the main menu.
We went ahead with the con-
stellation diagram.
Before the meter can dis-
play that diagram you have
to select either a pre-stored
channel or the current fre-
quency. In our case the set-
tings list was still empty,
which is why we chose the
current frequency which we
had selected with the marker
in the spectrum mode.
The constellation diagram
can display both QPSK and
8PSK modulations, with the
8PSK modulation being di-
vided up into nine squares
rather than eight segments
forming a circle. The QPSK
modulation is shown cor-
rectly with four squares.
Constellation diagrams are
created rapidly and with a
similar performance as in
our reference unit.
The following important
information is shown on the
screen:
• Frequency
• Symbol rate
• Polarisation
• Modulation
• Satellite name
• MER
• C/N
• BER
• FEC
• Two bar diagrams with
signal quality and signal level
given in percent
What did make us stop
short was the fact that the
display invariably present-
ed identical values for MER
and C/N, even though the
two parameters should be
measured
independently.
MER stands for Modulation
Error Ratio and indicates the
relationship between aver-
age signal performance and
average error performance
within a constellation.
In other words, the MER
value is a figure that corre-
lates with the size of a cloud
within a square of the con-
stellation diagram. C/N, on
the other hand, is short for
Carrier to Noise Ratio and
professional meters only of-
fer ASI as an additional op-
tion.
The bottom side of the de-
vice sports a USB interface,
an HDMI output, the power
socket for external power
supply (12V) and a common
interface for CAMs with full
CI+ compatibility – another
exclusive feature in this price
segment! The CI+ socket is
protected by a plastic flap
on the back side, which also
hides the battery pack which
can easily be changed when-
ever required.
Pressing the ‘On’ button
for two seconds powers up
the signal meter, and af-
ter approximately 15 sec-
onds it is ready to take your
commands. The main menu
boasts a neat design and we
did not even need to consult
the manual to find all the
functions we were looking
for. A total of eight options
are available from the main
menu:
• Spectrum analyzer
• Constellation diagram
• SAT finder
• SAT settings
• Angle calculation
• Memory functions
• System configuration
• USB options
In order to perform an ini-
tial quick test we hooked the
LNB cable from one of our
antennas (aligned towards
ASTRA 19.2E) to the meter
and selected ‘Spectrum ana-
lyzer’ in the main menu.
It was only a matter of
seconds until the spectrum
was created on the display,
showing a span of 1250 MHz.
In order to speed up spec-
trum refresh rates the fol-
lowing frequency spans are
available: 1250 MHz (full
span), 200 MHz, 100 MHz, 50
MHz and 32 MHz. The setting
can be changed loop-wise
with the ‘F1’ function key.
When in spectrum mode
the arrow buttons of the
signal meter take over very
useful functions: Using the
‘Up’ and ‘Down’ buttons you
can scroll along the y-axis
which displays the signal lev-
el. With the ‘Left’ and ‘Right’
buttons, on the other hand,
you can move a marker
along the x-axis, which dis-
plays the frequency value.
With this user concept it is
possible at any time to find
out the signal level of a se-
lected frequency and to initi-
ate a scan starting from the
marked frequency position.
This is a very useful fea-
ture if you need to align your
antenna to a more exotic
orbital position: Instead of
having to pre-edit the tran-
sponder list all you need to
do is move the marker to a
peaked signal within the dis-
played spectrum.
We truly appreciated the
fact that the Trimax TM6800+
locks a signal within a mere
second, provided the marker
is placed on a valid tran-
sponder. Pressing the ‘OK’
button will start a scan that
lists all channels in a matter
of seconds – a real treat for
feed hunters as well!
Unfortunately, the spec-
trum analyzer does not re-
act swiftly enough to allow
antenna alignment using the
spectrum display only. The