Help! Sat nav keeps losing signal

8154 Views 22 Replies 8 Participants Last post by pete4x4, May 6, 2009

GerryD

Discussion Starter · May 5, 2009

I have a Garmin C550 and a TomTom 930T, which I use in my motorhome. The motorhome is also fitted with a Phantom Pro-Active tracker, which uses GPS and GSM. At random times both sat nav units report a loss of GPS signal at identical times. The loss can then be for any duration of time up to possibly 1 hour. When the signal returns it is again seen by both units at the same time. It can then be lost several more time before stabilising.
When the signal is lost, I can remove the sat nav from the vehicle and walk away and the signal will then be detected.
I have tried an external aerial and that has given some relief to the unit mounted on the passenger side of the vehicle.
I have spoken to Phantom, who tell me that it is not possible for their unit to suffer a fault which would cause this phenomenon.
The motorhome is based on the new Fiat Ducato, which uses Canbus wiring.
I am unable to create this situation at will.
If I use the same combination in either of the other cars there is never a problem.
Can anybody help?
Gerry

1 - 20 of 23 Posts

Zebedee

· #2 · May 5, 2009

GerryD said:
When the signal is lost, I can remove the sat nav from the vehicle and walk away and the signal will then be detected.

Does this suggest that it happens only when the vehicle is stationary?

If so, take a note of the compass direction your van is pointing in at the time, since it has to be something shielding the signal.

If it happens only when the van points (say) North you will at least be able to avoid the problem - and will know the reason if it happens on the open road.

If my original assumption is wrong this is all garbage - so please ignore it. :roll:

Dave

123171

· #3 · May 5, 2009

Hi Gerry, l install trackers and sat nav's to the new type of fiat ducato/ peugeot boxer motorhomes and touch wood l havn't had a problem, but l did fit the GPS aerial behind the front headlight so it see's sky, ignition live for the tracker could be the problem, as it is cam bus, cheers Phil

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pete4x4

· #4 · May 5, 2009

It wouldn't be when you first plug your garmin in would it or when you turn the ignition on.
Garmin cigarette plug chargers have been known to cause horrendous interference.
Does the Sat nav regain satellites if you remove the charger?

Pete

GerryD

Discussion Starter · #5 · May 5, 2009

Thanks for the replies,
Dave - Nice try, but it happens when moving. Have to stop to test signal outside.

Phil - Thought of that, but Phantom say that the location of the aerial for the tracker cannot cause interference. The aerial is mounted within the dashboard.

Pete - Tried disconnecting all 12V accessories and switching off in order. Has no effect.

Gerry

chapter

· #6 · May 5, 2009

i had this with mine, its the overcab bed blocking the signal i bought an external antenna i now have a faster boot up and no signal breaks
chapter

pete4x4

· #7 · May 5, 2009

Something in the motorhome is clearly interfering. I take it this happens when the engine isn't running and your not on EHU

Edit, Most new SatNavs will now work indoors as long as they are not cold starting so the dash of a motorohome is no problem.

GerryD

Discussion Starter · #8 · May 5, 2009

chapter said:
i had this with mine, its the overcab bed blocking the signal i bought an external antenna i now have a faster boot up and no signal breaks
chapter

Thanks, but as I said I have tried an external aerial, no change.
Gerry

GerryD

Discussion Starter · #9 · May 5, 2009

pete4x4 said:
Something in the motorhome is clearly interfering. I take it this happens when the engine isn't running and your not on EHU

Edit, Most new SatNavs will now work indoors as long as they are not cold starting so the dash of a motorohome is no problem.

Pete,
It can happen when the motorhome is being driven, or at other times stationary on the drive with no engine running.
Gerry

rowley

· #10 · May 5, 2009

I had a Garmin unit which would always lose it's signal/crash on the Nottingham ring road near to Queens Med Centre. I assumed that something was blocking the signal but my Nokia N95 satnav does not show the problem.
I read somewhere on a Forum that there was a bad area near Luton airport.

Sorry Gerry, I can't help you.

pete4x4

· #11 · May 5, 2009

I take it your Phantom tracker works throughout all this?
A scenario that springs to mind is your tracker switches on to work out where it is but its active GPS antenna is faulty and is oscillating ie thas gone unstable. It continues to try for about an hour then gives up and turns back off.

The GPS antenna that is used by most tracking systems are all the same and they provide a lot of gain to overcome cable losses. I think your GPS antenna has gone unstable and is interfering with your other GPS units.

Next time it happens find out if your motorhome can be tracked, I suspect not.

Or have you done that already.

carolgavin

· #12 · May 5, 2009

Gerry hunny I know this will not help really :roll: :roll: :roll: but can lend you me new map if you don't wanna get lost

GerryD

Discussion Starter · #13 · May 5, 2009

pete4x4 said:
I take it your Phantom tracker works throughout all this?
A scenario that springs to mind is your tracker switches on to work out where it is but its active GPS antenna is faulty and is oscillating ie thas gone unstable. It continues to try for about an hour then gives up and turns back off.

The GPS antenna that is used by most tracking systems are all the same and they provide a lot of gain to overcome cable losses. I think your GPS antenna has gone unstable and is interfering with your other GPS units.

Next time it happens find out if your motorhome can be tracked, I suspect not.

Or have you done that already.

Pete,
Sort of tried that. Phoned Phantom on Saturday when we got to the rally, but by then the sat navs were working again. Haven't had the opportunity to phone them exactly when it was happening. Set it off on the motion detector this evening, but again by then the sat navs were receiving a signal although 10 minutes earlier they weren't.
Gerry

GerryD

Discussion Starter · #14 · May 5, 2009

carolgavin said:
Gerry hunny I know this will not help really :roll: :roll: :roll: but can lend you me new map if you don't wanna get lost

Carol,
We luvs you dearly but that was where the panic set in, when they lost signal on Saturday I got the map out and found that I couldn't remember how to use one.
Gerry

carolgavin

· #15 · May 5, 2009

GerryD said:
carolgavin said:

Gerry hunny I know this will not help really :roll: :roll: :roll: but can lend you me new map if you don't wanna get lost

Click to expand...

Carol,
We luvs you dearly but that was where the panic set in, when they lost signal on Saturday I got the map out and found that I couldn't remember how to use one.
Gerry

Shhhhhhhhhhhhhhh dunt tell, but I still cannot use one!!!

GerryD

Discussion Starter · #16 · May 5, 2009

carolgavin said:
GerryD said:

carolgavin said:

Gerry hunny I know this will not help really :roll: :roll: :roll: but can lend you me new map if you don't wanna get lost

Click to expand...

Carol,
We luvs you dearly but that was where the panic set in, when they lost signal on Saturday I got the map out and found that I couldn't remember how to use one.
Gerry

Click to expand...

Shhhhhhhhhhhhhhh dunt tell, but I still cannot use one!!!

You're not supposed to, you're a girlie. Maps are for you to rest the sweeties on as you feed them to Gavin. Like a portable table.

pete4x4

· #17 · May 6, 2009

GerryD said:
Pete,
Sort of tried that. Phoned Phantom on Saturday when we got to the rally, but by then the sat navs were working again. Haven't had the opportunity to phone them exactly when it was happening. Set it off on the motion detector this evening, but again by then the sat navs were receiving a signal although 10 minutes earlier they weren't.
Gerry

Hmmm, 10 mins probably isn't long enough for the tracker to want to get a new fix, I'd still try and find out if your tracker is working when this happens. It's the only thing I can think of that can be causing your problems.

GerryD

Discussion Starter · #18 · May 6, 2009

Pete,
Thanks for that, my thoughts entirely, but Phantom say that it is not possible. Rather short sighted of them as anything electrical can create an unexpected fault condition.
At least I know where it is mounted now so that if it happens again I can pull the plug and isolate the Phantom device. As this is the third unit I have my doubts about the quality of their product.
Gerry

pete4x4

· #19 · May 6, 2009

Don't forget I think it has 48 hours of internal battery backup so you probably need to disconnect the gps antenna if you can.

GerryD

Discussion Starter · #20 · May 6, 2009

pete4x4 said:
Don't forget I think it has 48 hours of internal battery backup so you probably need to disconnect the gps antenna if you can.

Good point, thanks for that tip.
Gerry

1 - 20 of 23 Posts

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