Troubleshooting GP33/GPA017

[lshick]

We have a GP33/GPA017, installed 2016. It mostly works fine, but a few weeks ago it developed a symptom where the reported position will wander by maybe 120', rarely more. By "wander" I mean that the reported position will move away from the proper position over the period of maybe 10 seconds, hang out at the extremity for maybe 10 seconds, then over maybe 10 seconds move back to the center point (see photo). The excursions tend to be to the west or west-north-west, but rarely other directions. The excursions may happen several times a day to several times an hour. This has happened at multiple locations, including at anchor with no other boats/structures within several hundred feet.

This would be no big deal except that I use the GP33 for the anchor alarm, so I get false alarms on anchor-dragging as a result.

Should I suspect the antenna or the display?

 

[jp498]

I'm guessing it's not seeing as many satellites as it should. Check the antenna connector on the back. Check the satellite constellation display page.. If it's seeing 4-5 sat, that's pretty weak. It should strongly receive 8-10 or more. If you get a antenna test is before routing the wire so you know that will fix it.

I have seen people DIY the coax connector so the cable will fit through small spaces, and I touch it, and piles of salty green blue copper powder fall down and the coax is freed from the connector....

 

[Titanic II]

First do the GPS reset in the System - Reset menu. This will do a GPS cold start to reacquire satellites.




If no improvement, then smooth the position out over a longer period, say 10 seconds. This will disregard temporary fluctuation is position.