Troubleshooting Gnss Reception - Spectracom PRISMA VelaSync User Manual

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Table 5-2:
5.1.5 Troubleshooting GNSS Reception
If VelaSync reports Holdover and/or Time Sync Alarms caused by insufficient GNSS reception:
When a GNSS receiver is installed in VelaSync, a GNSS antenna can be connected to the rear
panel antenna connector via a coax cable to allow it to track several satellites in order for
GNSS to be an available input reference. Many factors can prevent the ability for the GNSS
receiver to be able to track the minimum number of satellites.
With the GNSS antenna installed outdoors, with a good view of the sky (the view of the sky is
not being blocked by obstructions), VelaSync will typically track between 5-10 satellites (the
maximum possible is 12 satellites). If the antenna's view of the sky is hindered, or if there is a
problem with the GNSS antenna installation, the GNSS receiver may only be able to a few
satellites or may not be able to track any satellites at all.
When GNSS is a configured time or 1PPS input reference, if the GNSS receiver is unable to
continuously track at least four satellites (until the initial GNSS survey has been completed) or at
least one satellite thereafter, the GNSS signal will not be considered valid. If no other inputs
are enabled and available, VelaSync may not initially be able to go into time sync. Or, if
GNSS reception is subsequently lost after initially achieving time sync, VelaSync will go into the
Holdover mode. If GNSS reception is not restored before the Holdover period expires (and no
other input references become available) VelaSync will go out of sync. The GNSS reception
issue needs to be troubleshot in order to regain time sync.
For additional information on troubleshooting GNSS reception issues with VelaSync, please
refer to the GNSS Reception Troubleshooting Guide , available
196
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Troubleshooting using the Web UI Status indications
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The following This message is displayed when any
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displayed: Access Rules table and your PC is not
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don't have per- address.To restore access to the
mission to Web UI, either
access/ on this 1. Login from a PC that is listed as an
server" Allow From in this table; or
2. If it is unknown what PCs have been
listed in the Access table, perform an
unrestrict
remove all entries from the Network
Access Rules table. This will allow all
PCs to be able to access the Web UI.
here
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Troubleshooting
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