GPS broke

[alahol2]

I've an old Garmin GPS fitted to the boat (can't even remember the type offhand) which stopped working this year, 'Can't find satelites'. It's the type that uses an external 'mushroom' aerial. Is there a test I can do on the aerial to tell me if the wires are broken? Should I see continuity? (I have tried walking round the yard to see if I can see another aerial on which to try the display, without success).
Any thoughts?

 

[awol]

The top of Garmin mushroom aerials just unscrew though the threads will have been gunged with a silicone like rubber. Continuity checks can then be made on the cable. Memory says it is just 50 ohm co-ax and will suffer from water ingress at any pinhole and unlike vhf will then stop working totally.

The other problem I've had is with the BNC connector at the display head - a squirt of your favourite WD40/Duck Oil/whatever may be enough to fix it.

 

[Skyva_2]

If it is not working Garmin Europe might be able to replace it - they do not normally charge.

 

[freebird1]

mine did same. replaced aerial. no probs after.

 

[Ruffles]

Is the boat hauled out? I thought mine was faulty one winter. Turned out it was because the boat was on the hard and there was a tree in the way. The older units are a lot less sensitive than the new ones.

 

[lw395]

GPS aerials actually have part of the receiver built in. They generally get a 5V supply (sometimes 3V) on the centre of the coax.
Almost all gps antennas are interchangeable, so you can borrow one to test your receiver. Or buy one of the car ones from ebay for a few quid, but be aware that many of these need to be on a metal surface to work properly.

 

[tonykerry]

I had the antenna go faulty on my Garmin GPS120. (proved by swapping the display onto a friend's boat). I purchased a new antenna on EBay for £2.95 + £3.45 P&P from Digitalwonders. Specify BNC connector. The new antenna just sits next to the GPS and works better than the original.
Regards, Tony

 

[VicMallows]

Almost certainly a connection fault between set and antenna. The BNC connector at the set end of mine caused trouble .... probably because it's a straight connector and gets bent rather too acutely. When you test with a multimeter on 'diode' range (usually 2kohm) the antenna should appear as a diode...ie low resitance with connections one way around, high the other.

Vic

 

[alahol2]

That's great everyone, thanks.
I'll do the checks, and failing repair of the cable, I'll try a new E-bay aerial.
As a resource this forum never fails to amaze with its range of knowledge.