[TG] [TG11] No Fix, TX timeout at fixed time

[Tom - Raymarine - Moderator]

Hello Crossroads,

Yes, I think that the cause is indeed quite likely to be the particular combination, locations and signal levels of the satellites in view at the time. It might be that you have a low signal level because of the location of the antenna or a bit of background RF interference on the boat and that that's combining with the sats-in-view to produce the lost fix at that particular time of the day.

I'd suggest connecting your computer over USB to the AIS and running the ProAIS 2 software which will give diagnostic information about the GPS signal levels. Have a look at the overall signal levels at times when the AIS does have a GPS fix, and the locations in the sky, and then see what changes at the time when the unit has lost fix.

The alternative is that it is possible that the problem is interference from something on-board that's being turned on, used etc. regularly at that time in the morning (genset, watermaker on a timer for example?) If the problem were only occuring in one location then I'd add to this shore-based interference, but that clearly doesn't apply in your case. Interference with GPS is surprisingly common because it's such an incredibly low-power radio signal.

Regards,
Tom