Garmin GPS Satellite Acquisition Failure

[miyagimoon]

On Sunday 29th March, yesterday, and today our Garmin GPS/Chartplotter could not acquire satellite communication for a number of hours during the day. Our other GPS/ Chartplotter unit (Standard Horizon) did not have any problems acquiring the satelitte links. At first I thought there was a problem with the unit. However, another yacht in the same anchorage had exactly the same problem, their Garmin failed whilst their Lawrence suceeded.

We are both sailing in Greece between Preveza and Vliho.

Has anyone else had similar problems and does anyone know why this has happened?

I assume Garmin have put money in the meter!

 

[RAI]

I'd guess at local interference, maybe intermodulation products, combined with the Garmin chip sets being older / less capable than the others at acquiring / hanging on to a weak signal in a noisy environment.

 

[Jeannius]

The Raymarine unit attached to my guardrail gradually got slower and slower at acquiring a signal. Eventually I had to get it replaced when it was 6 years old.

The units with all the works inside the antenna can apparently just deteriorate over time.

 

[Pete7]

Ae you aware the Raymarine 125 have watch batteries inside. Took a while for Raymarine to confirm this, but eventually they did with a scan of the circuit board mit batteries.

Back to the Garmin, the weakness I think is the BNC connector on the back of the unit if this is exposed. If you have enough cable cut a length off back to clean shield and re-make the connection. Had to do a Garmin 188c a couple of times over the last 5 years because its mounted in an exposed location.

Pete

 

[Jeannius]

[ QUOTE ]
Ae you aware the Raymarine 125 have watch batteries inside. Took a while for Raymarine to confirm this, but eventually they did with a scan of the circuit board mit batteries.


[/ QUOTE ] No I wasn't and the people supplying the new one certainly didn't mention it!


Not sure it was that unit and too late to find out now. Anyway, I'll no next time. Thanks

 

[noelex]

Hi MiagiMoon
Are you sure Charlie has not been Chewing on the aerial?

The most common reason for this type of problem is a poor aerial connection (particularly with passive antennas). The second most common reason is failure of the internal battery in the GPS. This latter problem shows itself usually first by slow initial fixes when the unit is turned on combined with loss of fix as you experienced.
However I think your problem is more likely to be the appearency of the new EGNOS GPS sattalite. This new sattalite provides differential feed and has been upsetting some older GPS units when it comes into view.
A software update, if available, from Garman would solve the problem. Without the software change some older units are very confused when this satellite appears.
The differential satellites number is higher. Have a look at the received satellites. The number of the new sattalite is higher than the older units. I think 132 from memory.

 

[noelex]

On some GPS units you can turn off the satellite differential fix, this may not solve the problem even if it is the new satellite, but is worth a try.

 

[lenseman]

[ QUOTE ]
No I wasn't and the people supplying the new one certainly didn't mention it!

[/ QUOTE ]
Of course not, they want to sell you a new unit. /forums/images/graemlins/confused.gif

 

[Pete7]

Copy of a scan showing the inside of a Raymarine 125 GPS unit. Bit late for you now but for forumites future reference looks like Varta CR series and I think there are two of them.

Pete