Garmin nuvi 310D GTM12 TMC problems

[wilburforce]

contact type: cable from pc

Inside the house i have never been able to get traffic reports.
Once outside in car.


method: Silver foil wrapped the middle to top end with me holding end (inside house).

***bingo traffic reports in house**** in 30-40 seconds

All i can conclude is that (so far) my signal is weak or my aerial is as about as much use as achocolate fire guard.

will try in car please tell me if you get the same? :o :o

[RDS]

Not sure if by 'TT510 with aerial' you mean TMC receiver but Tom Tom don't yet have a TMC receiver available.

It will be interesting when they do as currently Garmin are one of the few manufactureres who have TMC receivers on sale and so consequently many have gone for a Garmin GPS over one from Tom Tom.

Although suggested release dates have been and gone I'd imagine it's only a month or two before Tom Tom finally have theirs on sale (although it doesn't mean a lot Argos have one listed in their new catalogue)

Consequently Garmin do really need to nail the TMC problems many are now experiencing otherwise they could well lose quite a few sales to their main competitor. Of course that's assuming Tom Tom don't bring another substandard product to the market as in the dodgy x10 series mount fiasco !!

[mikealder]

[n4nick]

Hi Swing

Yes, I have tried the nuvi GTM12 plugged into the computer and it works so the problem would appear to be the power supply when in the car. I have a new golf so wouldn't be expecting any problems with the socket itself (I have plugged it into both the in-car and in-boot one). Will try this out in my parent's car later today. As you know I have also tried the two different Garmin power cables too. I don't have a USB car power cable though but don't really want to purchase one and therefore throw more money away on this problem!

Nick

[JT-Mech]

The Citroen C5 comes with Traffic Master Oracle as std which was connected via the powered roof aerial, if you replace the TM control unit you dont use the old aerial as it now comes with one attached, it's a crappy bit of wire the same as the TMC 12, but 'T' shaped and about 9 inches wide that you hide behind the dash the best you can, the trouble is that it works perfectly.

[swing]

[swing]

Hmm, even more investigations...

The reason TMC is a big flakey for me at home is that I lay the aerial across the dashboard, whereas whilst parked in the drive the only direction the aerial gets a strong enough signal is when the cable is pointed towards the offside rear corner of the car... (However, with it in that position, it got plenty of traffic reports, even for a Sunday afternoon...)

Having said that, the longer USB cable I was trying results in a signal level approx. 1 or 2 less than the Garmin cable, so I'm sticking with that for the short term.

So, one thing to remember if you are trying to get a signal to test the unit in the car, you may simply need to hold the aerial on a different alignment to get the signal. I found, for example, holding it vertically (or using the suckers to attach it upright to the windscreen) made things no better.

[swing]

Correction: TMC is a bit flakey

Also, I should point out that the same 1 or 2 level drop experienced with the longer USB cable is the same 1 or 2 level drop that I get with the supplied charging cable - ie in Garmin's level scale (from 1 to 6), you need 4 or higher for it to lock onto a station and receive traffic - the longer cable and the supplied charging cable were running my local RDS-TMC radio station at 2 or 3 (depening on the location of the cable), which is just too low for it to lock on - at below 3 it seems to want to keep searching for a stronger signal.

So, it seems, it's just on the cusp between receiving and not receiving any data, and there are many factors that influence it, but unfortunately, one is definitely the amount of power (in some way) being sent to the Nuvi...

[mikealder]

Hence my comment regarding an external aerial connection, a true outside aerial has got to perform better than the supplied "string" - I don't think it will be required everwhere, but it would be nice to have the option, your tests so far indicate that your unit would receive data/ signals better if fed with a stronger signal - Mike

[n4nick]

Hi Swing

Are you refering to a receiver strength indicator (Garmin level 1-6)? I can't find one of these on my Nuvi 310 (apart from the GPS one) which I don't think is related to TMC?

Thanks - Nick

[swing]

Yes, I am :D

However, it's not on the normal Nuvi interface, you have to go into the Diagnostic mode to see it - from the trip computer press and hold the Average Speed for 4 or more seconds - if you press Next about 6 times you end up on the GTM status screen, where there is a Level indicator. I've fathomed out most of the other value meanings on that page too. Unlike the "other" set of diagnostic screens, you can Quit these and be back to normal. Howver, there are some buttons in there that are best not pressed, so a) be careful, and b) don't blame me if you break something.

mikealder - yes, you're correct my unit would work better with a stronger signal, however, the single thing that varied that signal so far is the power supply to the Nuvi, not the aerial connection!

[n4nick]

Hi Swing

Disclaimer noted, perhaps this is best left alone. By the way, how did you find out about this screen? Are there any other interesting "hidden" screens on the Nuvi which might be useful to users?

Nick

[banjo12]

This is strange, my car is kept in a garage and I have left my Nuvi 31D on charge, every time that I have turned it on the traffic icon has become live after about 6 seconds and the list has started to populate.

At about 12.15pm today I disconnected the power lead so no charge for about 7 hrs, I then plugged the power lead back in and turned the unit on and the traffic icon stayed grayed out no matter how long I waited ?

I put it back on charge and after about an hour it went back to normal ie traffic info after about 6 seconds, any comments !

[mikealder]

This is indicative of insufficient power (current) being supplied by the car adaptor, when fully charged the battery will consume less power from the charger than in a depleted state, leaving more available for other usage.
When more power (current) is being pulled by the battery for charging purposes there is insufficient reserve to power the TMC module correctly, therefore it fails to power up fully/ correctly and you get no data.

Keep the main unit fully charged and you should be OK as you have already intimated.

I have seen the same thing with a wired GPS unit feeding a PDA from a Y cable, the PDA had a very large but low charge state battery i.e. nearly flat, the result, no GPS for 60 miles - basic laws of supply and demand I am afraid, if the adaptor isn't up to the total cumulative load then some part of the circuit will suffer, in your case the TMC part - Mike

[wilburforce]

Well I have tested most of the day.

What I found was this:
Using the usb and leaving the aerial in a standard place in the house no signal.

While holding the end I get a signal, in fact it is quite easy, so there is power enough using a USB connection and with some manipulation the aerial will receive, still not good enough for £120.

In the car well with the screen set to low No Bluetooth (all in a bid to save power) I have no joy at in connecting to any traffic data.

Personally I expect that the aerial is not up to standard and the power is simply not sufficient to amply the signal for the aerial. This confirms all the previous forums on the subject.

Garmin must sort this out they have a dead product here, at best working by very few people. Bear this in mind you pay for a service not an intermittent one.

My aerial will be going back tomorrow the unit will stay, im sure gamin will sort it, but then the price will fall and I will buy an aerial which works.
:P

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