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2 demodulator configuration – Comtech EF Data MDX420 SkyWire Manual User Manual

Page 65

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MDX420 SkyWire™ Satellite Network Gateway

SkyWire Controller (GUI)

MN-MDX420 Revision 6

7–9

If the Auto Start function is enabled, the MDX-420 determines if it can receive the designated
share group’s channel.
If there is no share group carrier to receive, the MDX-420 attempts to start the network.
Wait one minute
Go to step 1.

NOTE: It is NOT recommended that Auto Start be enabled on more than one MDX-420 within a
share group.

The decision as to which, if any, MDX-420 has the Auto Start function enabled should include the
following two considerations:

Likelihood of a signal outage at that site – If possible, select an MDX-420 at a site that
has the least chance of an outage.
Access to the MDX-420 – If possible, select an MDX-420 to which the network
administrator has either direct or non-over-the-air access.

 Network Spec: Network spec is set to RADYNE MESH and is not changeable at this time.

 Performance: The Performance selection can be set to Standard or Enhanced. This setting must

be the same for all units that are transmitting into the same share group. The performance
setting is a trade-off of Eb/No required to close the link and bandwidth efficiency. See the below
table to understand how this setting will affect network performance:

 Selected Demod: The Selected Demod is the demod that is associated with the modulated signal.

Every MDX-420 that is transmitting into a share group must be locally demodulated in order to
meet timing and BW sharing algorithm criteria. The Selected Demod is the physical demod slot
that is associated with the modulator’s share group. By default this is demod slot 1 as this demod
is always populated from the factory. The demod can be set to any populated demod slot if more
than one demod is purchased and installed in the MDX-420. A Selected Demod setting of “0”
means that the MDX-420 is in a listen only mode and can not transmit into any share group.

 Selected Remote: The Selected Remote is automatically assigned by the network and can not

be changed. This number correlates to the physical location on the GUI interface. A number of 2
for example would indicate that this site is in position 2 of the bar graph of a multiple site share
group. Note: each share group will re-start the count so the number of the remote will always be
between 1-8 for a particular share group. Alternatively, when viewing the GUI interface, the
“yellow” bar is another way to know what MDX-420 device you have the SNMP session with.

 Gateway ID: This is the unique ID that each MDX420 shipps with. This unique ID will be

required by the SkyWire Configuration Controller and should be recorded by the network
administrator. NOTE: The Gateway ID will be needed to configure the network (see section 7.6).

 All other configurable items in the modulator configuration screen should be treated as if

configuring any other satellite modem.

7.4.1.2 Demodulator

Configuration

There are up to four burst demodulators that may be installed in the SkyWire Gateway. To
configure any of the installed burst demodulators, select the corresponding demod tab. Press the

Modulation and Coding

Threshold Eb/No

Typical Eb/No

Efficiency

1) Enhanced - QPSK.710

2.9

3.5

90%

2) Enhanced - QPSK.793

3.3

3.8

90%

3) Standard - QPSK.793

3.4

4.4

93%

4) Enhanced - 8PSK.793

6.5

7.6

88%

5) Standard - 8PSK.793

7.8

9.0

91%