[time-nuts] Trimble Resolution [T, SMT, SMT GG] - spontaneous GPS loss of signal events, multiple locations

[Azelio Boriani]

Why there are distribution amps? If there are other non-Resolution
receivers (co-located and driven by the same antenna/distribution
amp), what are they experiencing when there is the outage reported by
the Resolution boards? Less-than-usual satellite count? Poor C/N? Can
you log data?

On Mon, Sep 14, 2015 at 1:28 PM, Wojciech Owczarek
<wojciech at owczarek.co.uk> wrote:
> Hello Time Nuts,
>
> I was wondering if other people have seen this. 20+ receivers and they all
> use different variants of the Resolution boards - majority are the old
> Resolution T.We have observed sudden GPS loss of signal occurring.
> Seemingly nothing unusual, these things happen, that's what holdover is
> for, etc... however:
>
> - All devices are connected via decent distribution amps,
> - All installations use roof-mounted antennas with unobstructed 180 degree
> sky view
> - All devices see about 11 birds most of the time
> - None of these events coincided with known GPS SV outages
>
> And here's the fun part:
>
> - This is happening in multiple locations in the US, AND in the UK
> - The log timestamps (UTC) for the alarms, are *exactly the same* across
> all sites, down to the second. This happens twenty to ten seconds before
> midnight, and usually recovers within two or three minutes.
>
> The last event was on 5th September, at 23:59:37 UTC. We have seen this
> happening anywhere between once every month to once every two months. Time
> may differ by a few seconds, but it's the same across all devices.
>
> I'm trying to establish whether the issue is with Trimble or with the
> vendor who embedded Trimble. Because of what I refer to as "vendor
> anal-digital decoupling delay", I have to investigate in parallel.
>
> Has anyone seen this with Resolution? Unfortunately I have no visibility
> into firmware versions in the Resolution boards.
>
> Any pointers welcome.
>
> Many thanks,
> Wojciech
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