1. TEST REPORT Multiswitches
Max Communication Chess
Multiswitches 17/6 NT & 17/6 K
Distribution solution for a family
house or a block of apartments
Multiswitches are very useful devices when you distribute the signal from either a single dish or from –20 through + 60° C - so
need to distribute satellite signal to several rooms a few dishes to several receivers. Max Communi- this should not pose a problem
while keeping a number of dishes to a reasonable cations has provided us with two types of multi- for them. Keep in mind, though,
minimum. Depending on model, they allow you to switches that can cooperate with each other. that they are not to be operated
outdoors.
satellite “A” will be available to
them. Of course, we are speaking In the Practice
here about reception in Ku-band, Time to take a few measure-
as the Quatro LNB implies. ments of Chess 17/6 NT. Every
satellite input coming from
Except for the 17 inputs and Quatro LNB is somewhat attenu-
6 outputs, the multiswitch addi- ated by the multiswitch. Accord-
tionally has 17 cascade (pass- ing to specification, before it
through) outputs. They are reaches the receiver it is down by
used to connect Chess 17/6 K 5 dB ±2 dB. We obtained in our
unit. Chess 17/6 K is an exten- measurements results from –2
sion device that when connected through –8.5 dB depending on
to the base model increases the the receiver output used and the
number of outputs from 6 to 12. input frequency (see figure 1).
According to the manufacturer,
Chess 17/6 NT connect the terrestrial antenna.
As you can probably figure out,
by cascading more 17/6 K’s, you
may get 18, 24 or even 30 out-
But how does the multiswitch
influence the quality of signal? We
The Chess 17/6 NT is designed this model has 6 outputs. So, puts. Such system can distribute measured the C/N ratio before
to deal with 4 dishes equipped with you can connect up to 6 satellite satellite signal in a block of apart- and after the multiswitch for 2
Quatro LNB’s. That gives us 16 receivers. A living room, a study ments. different signals. For the receiver
inputs. An important advantage plus 4 bedrooms - very good output, we observed that it went
of the system with a multiswitch solution for a family house. In most cases, a multiswitch down 0.8 dB from 10.3 to 9.5 dB.
is that only one coaxial cable is You will be able to receive any will be put close to the roof of For the pass through output C/N
required between the switch and channel from anyone of the four the building where the tempera- degraded from 11.5 to 11.0 dB.
a receiver. Since almost every- satellites independently of what ture can vary significantly. The It is negligible for strong signals
body wants to receive terrestrial is being received on the set-top- units described in this report can (e.g. those from Astra or Hotbird
transmission along with the sat- boxes in other rooms. There’s operate in the temperature range in Europe) but may pose prob-
ellite channels, multiswitches are only one condition: your receivers
designed to transfer also terres- must be compatible with DiSEqC.
trial signal down the same cable. Otherwise, they will not be able
Input number 17 is dedicated to to switch among satellites – only
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2. lem for weak satellites. How-
ever, one can not expect here a
miracle. Distributing weak signals
(or signals with low C/N ratio)
will always be a problem for any
switch, splitter or cabling. Chess
multiswitches are not at all bad in
this respect.
The multiswitch is marked as
DiSEqC 2.0 compatible. It means
that it should work with a receiver
using DiSEqC 1.0 to choose a sat-
ellite. We tried it and the system selected on a given output has no
was working flawlessly. “Tone- effect on the signals on any other
burst” switching also worked but output. There was nothing we
one could select only satellite A or could observe or measure. So the
B with this simple method. isolation among the inputs/out- you should insert amplifiers ment range is even slightly higher
puts is quite satisfactory. between the LNB’s and the base – about 11.5 dB.
The terrestrial signal is sig- multiswitch inputs. Usually, 20 dB
nificantly attenuated when com-
bined with the IF signal inside Cascading amplifiers are added here. In a
cascaded network, you will need Conclusion
the multiswitch. The loss of 16
dB ±2 dB means that you must Multiswitches to use the attenuators built-in
in every IF input to equalize the
The bold manufacturer’s state-
ment about getting 24 or even
use a 20dB amplifier between After measuring the single outputs from the different mul- 30 receiver outputs with Chess
the terrestrial antenna and the switch, the next necessary step tiswitches. Without the attenu- 17/6 NT and a number of 17/6 K’s
switch to compensate for the was to connect another switch ators, the multiswitch closest to seems to be quite feasible if you
loss. This is something you must Chess 17/6 K to the system to the LNB will always provide the install additional 20dB amplifiers
take into account when designing increase the number of receiver output of the highest level, and between LNB’s and the first multi-
the whole antenna system. Our outputs to 12. However, before every next multiswitch a few dB switch. However due to high pass-
tests have revealed differences that, we checked the IF pass weaker signal. So our next job through losses for the terrestrial
in the frequency response of the through loss. We have got values was to measure if we really have signal, we would recommend not
6 receiver outputs for the ter- from 5.5 dB for 969 MHz and 6.0 10 dB of attenuation adjustment to use the cascade outputs for
restrial signal. Some of them had dB for 1912 MHz. For the 17/6 K, available as specified. Our meas- distributing this signal but install
almost perfectly flat response (1- we got 4.0 dB and 3.8 dB for 969 urements revealed the adjust- additional splitter and route the
2 dB ripple or so) in the whole 47- and 1912 MHz respectively. If you signal individually to every multi-
862 MHz range but the others had compare them with the speci- switch terrestrial input.
larger peaks and dips. The worst fied values, you will see that the
TECHNIC
DATA
passband ripple we measured manufacturer was too optimistic
Manufacturer Max Communication GmbH, Siemensstr. 53,
was almost 10 dB on one of the here. Total signal attenuation at 25462 Rellingen, Germany,
receiver outputs. Specification the 17/6 K connected in a cas- http://www.maxcommunication.de/
permits only ±2 dB. That means cade with a 17/6 NT is presented E-mail info@max-communication.de
that in some situations, you will in figure 2. Pass-through 1 is the
Phone +49 4101 / 6060-0
be able to notice a difference of output of 17/6 NT being at the
Fax +49 4101 / 6060-9 99
the terrestrial TV quality depend- same the input for 17/6 K. Pass-
ing on the receiver output being through 2 is the output of 17/6K Models Chess 17/6 NT and 17/6 K
used. for the following multiswitch. Rx Description Chess 17/6 NT - mutliswitch with
out is the signal level at one of the embedded power supply.
We checked if the signal the receiver’s outputs of 17/6 K. Chess 17/6 K – extension to NT with
present on one input can induce additional 6 receiver outputs
some interference on the other As you can see, the signal Inputs 16 satellite + 1 terrestrial
inputs and did not find anything passed through by the 17/6 NT Receiver outputs 6
wrong here. The same applies to to 17/6 K is attenuated. If you Cascade outputs 17
the receiver outputs. The signal want to cascade multiswitches, Input frequency 950-2150 MHz (Sat.) and 47-862 MHz (Terr.)
Expert conclusion
IF tap loss 5 dB ±2 dB
IF input attenuation adjustment range 0 … 10dB
+ IF pass-through loss
Terrestrial tap loss
1.5 dB for 950 MHz, 3.5 dB for 2300 MHz
16 dB ±2 dB
Excellent isolation between different inputs and
outputs keeps interference below the reception Terrestrial pass-through loss 5 dB
threshold. Low noise. Low current drown from a Isolation between satellite inputs > 30 dB
receiver – below 20 mA. Isolation between satellite and > 35 dB
-
Peter Miller terrestrial inputs
TELE-satellite
Test Center Current drawn from receiver 60 mA max.
Signal losses are slightly higher than specified. No Poland
Embedded power supply 12V/1600 mA
built-in amplifiers – you must buy them separately.
(NT model only)
Flatness of the frequency response for the terrestrial band leaves
Polarization switching voltage 14.5-15.5 V
something to be desired for some outputs. Significant pass-through
attenuation for the terrestrial signal makes cascading this signal Band switching frequency 22 kHz ±4 kHz
rather impractical. Operating temperature range -20… + 60° C/dry indoor use
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