Garmin nuvi 310D GTM12 TMC problems

mwfox · Posted: Sun Oct 22, 2006 10:01 pm Post subject:

What TMC unit have you got pandamedic? The final fix charger for the GTM 12 ends 6025 - and they (in US) aren't working on a new fix.

pandamedic · Occasional Visitor Joined: Oct 25, 2004 Posts: 50

mwfox · Posted: Mon Oct 23, 2006 9:54 am Post subject:

I wish Garmin would make their mind up - they keep telling people different things!!

mwfox · Posted: Mon Oct 23, 2006 4:00 pm Post subject:

Have you read the above message Swing - do you know what the charger 022455 is? and the comment about bringing out another charger from the US in the New Year. (I saw on another forum 022455 was an old one).

Does it have a red/green LED or just a red one Pandamedic and does it have another code on it?

swing · Posted: Mon Oct 23, 2006 7:03 pm Post subject:

mabsey · Occasional Visitor Joined: Aug 08, 2006 Posts: 43

The latest I've just been told by Garmin after complaining the 6025 wasn't that much better :

Quote "I'm sorry but the GTM12 will only work on Some of the Major Roads and Cities within the UK due to the weak FM Signal!

WTF!

£140 for Patch Traffic is a complete Rip-off.

Mabsey

swing · Posted: Tue Oct 24, 2006 2:45 pm Post subject:

Although it may not have been well worded, I can understand Garmin saying that. Certainly the signals are stronger near large cities, which often means the more countrified roads have weaker signals, and hence the bit about main roads - certainly hilly country roads will naturally have a lower signal level (partly being further from the transmitters and partly due to the hills!) and hence it will work less places.

I think Garmin's biggest problem is twofold:

1. It works in every other country
2. They never mentioned any of this until after the units were on sale (*)

(*) I appreciate Garmin do say something like "where traffic coverage is available", and I can understand their Marketing isn't going to say "Although don't bother buying it in the UK as the signal is so poor, it'll hardly work".

What would be nice is some changes to the software coding within the Garmin - maybe holding onto the traffic data for longer when reception is lost (or becomes patchy) so that the unit doesn't think the traffic has cleared up everywhere magically.

mikealder · Posted: Tue Oct 24, 2006 6:28 pm Post subject:

Well if you live in a poor reception area I do - (Blackpool isn't to clever for any of the TMC units to be honest). Prompted by the thread on the -21 receiver I have today tried a couple of external aerials hooked up to my GTM-12 receiver.

First off the unit was tried without an external feed i.e. as supplied when I checked the signal strength it was only 3 for the local station (channel 179 works best around here).

I then stripped about 3MM of insulation from the end of the Garmin "shoe string" aerial and soldered this to a 3,5MM mono jack socket.

This socket was first connected to the Maplins mag mount I have (part number QT30H ) the signal level increased to a 6 and TMC data started to flow, disconnection of the external feed caused the receiver to resume scanning and not receiving any data. This aerial is not ideal as it is designed for use at frequencies above 100MHz, but it does improve the situation.

Next was to connect it to the Hirschman GPS 9 18 V Flex, ok the write up I did was for use with Classic FM and iTIS TMC data, but it works in the same frequency band as the TrafficMaster transmisions. I coupled the GTM-12 to the FM part of the aerial, the signal strength increased to a 9 again TMC data started to be received, disconnection and the reception stopped with the signal strength dropping back to a 2 or 3 - no data.

Hardly the ideal situation having to use an external aerial, but it does make a considerable difference in poor signal strength areas, through out this short test the car was not moved - engine was running to provide the electrical noise you would normally encounter when driving.

At weekend I will try and bury the Garmin cable under the dash, still connected to the Hirschman and see what happens, if this works I will be happy as it will reduce the number of cables across the dashboard - Mike

swing · Posted: Tue Oct 24, 2006 6:53 pm Post subject:

mikealder · Posted: Tue Oct 24, 2006 7:09 pm Post subject:

Swing, the reason I typed 3,5MM is because I have one in front of me, the one in the car (on the aerial) is actually 2,5MM Embarassed

it is a mono plug that I fitted to the aerial as this connects to a different TMC receiver.
Centre core of the coax goes to the centre pin of jack plug, screen of the coax goes to the outer connection of the plug.

I modified the aerial when I got it, I don't like using addapters as they add losses to the signal path, given a true install I would solder the joint, but I need the flexibility the jack plug offers, at the same time I changed the plug I also shortened the supplied coax lead at 10M its a tad too long.

With the plug fitted and in use I decided the easy option was to fit a 2,5MM socket to the end of the Garmin "Shoe String" thus I can easily disconnect the device, and still use it with the other receiver when required.

Any decent quality car aerial should work as they are desinged for opperation using the FM frequency band, the one you link to will work, but I am not too sure about a mount for the vehicle, I use the Hirschman feed in my own car, and the Maplins aerial for use in hire cars, at £15 for the mag mount aerial its worth a try, BUT please bear in mind cutting the plastic tab off the end of the Garmin shoe string aerial and soldering a conector to the end will invalidate the waranty - Mike

JoshT · Posted: Tue Oct 24, 2006 7:33 pm Post subject:

Mike,

If you had a Y cable from the back of your car radio could you connect the GTM 12/21 wire aerial to the centre pin? Do you think this would work?

You then wouldn't have to buy a separate aeriel.

Thanks

Josh

mikealder · Posted: Tue Oct 24, 2006 9:14 pm Post subject:

mwfox · Posted: Wed Oct 25, 2006 5:51 pm Post subject:

Has the shoe string GTM 12 aerial wire - just got a single wire ie no outer covering wire?

mikealder · Posted: Wed Oct 25, 2006 6:42 pm Post subject:

Single wire, multi-stranded copper, there is no screen to connect - without breaking open the actual module, which I have not tried as it looks very well sealed up - Mike

pandamedic · Occasional Visitor Joined: Oct 25, 2004 Posts: 50

The cable that came with my nuvi in the box back in april time is this one

P/N: 320-00239-21 .............10R-02 6025
The LED is RED when off, and RED when on. Never seen it go green even when the battery is full. Pic below

The new cable Garmin sent me a couple of weeks ago is this one. with an extra thing on the cable is

P/N: 320-00239-21 .............022455
The LED is RED when off, and RED when on. Never seen it go green even when the battery is full. Pic below

All i know is that the 6025 is crap with my traffic and is hit and miss. didn't get traffic once from heathrow to birmingham.

The 022455 cable gives me traffic from the time it's switched everytime and i get pages of it updated all the time, except for when i'm around the stafford area for some reason....i contacted trafficmaster and they said this in an email

Unfortunately we here at Trafficmaster only supply Garmin with the Traffic Information for them to be able to supply the service. We do not take part in any upkeep of technical issues or subscriptions. For this reason I must direct you back to Garmin Customer Services on 01794 519 944 who will be happy to help.

Either way i'm happy now with the replacement cable and my traffic. I hope the pictures help you regarding which cable is which[/img]

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