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Posted: Wed Aug 08, 2007 7:40 am Post subject: But what does it Mean! GTM Status page
Hi All,
Any help would be appreciated. I've just bought a Nuvi 350, and a GTM 12 module and I'm not getting any traffic messages. I've updated maps (V 9 NT+), Software and firmware ( Nuvi software 4.6, Audio version 1.4, GTM 4.4, GPS SW 2.9), and still no traffic (the traffic icon appears but stays light blue). I've checked the subscriptions and it varies from RAC Live to Tm TMC Life time subscriptions.
After reading through the forums I've found how to access the GTM status page (press the eta/speed area, then hold the Moving Avg area for a while, then when screen changes click next 5 times). And this is what I see:
Tuned Channel: 134 (mostly, but jumps all over)
cc: 12
SID: 128
LTN: 0
LEVEL: 25-56
ERROR: 0
MODE: 2 or3
N-SYNC 255 (SOMETIMES 0)
LAST MESSAGE: 0
MESSAGE COUNT:0
My problem is I don;t know what it means. By the Tuned Channel and Level, I'm assuming that I'm in a signal area, but not getting any messages. Is it that these channels are not broadcasting the TMC info.
I've driven round the London area so I've hit some pretty heavy traffic (M1, A1, A41, A406, M25).
The casuse as far as I can make out:
1. GTM 12 is just not working (But why am I getting signal??)
2. I'm not in a TMC traffic area. How can I check where transmitters are?
3. The stations I connect to are interfering (Is there a list of stations to ID's somewhere?)
4. The Nuvi is ignoring the messages (I think this unlikely, but the firmware may be doing this).
Is there anyone else in or about the London to St Albans area with a Nuvi and a GTM 12 that has similar issues?
Joined: Nov 04, 2003 Posts: 2225 Location: Bedfordshire, UK
Posted: Wed Aug 08, 2007 5:51 pm Post subject:
That's a poor (in my experience) TMC area. Having said that, I would expect some signal around St. Alban's - if, for example, I'm heading around the M25, I expect TMC signal from J21 (Hemel) through to J22 (London Colney) - ie if travelling anti-clock it starts at j21, if travelling clockwise it starts at j22.
Certainly Hemel seems to have a good signal - eg heading up the A41 from the M25, or into Hemel itself, so I would suggest a quick drive round and park up just off M25 on Watford Road (heading towards Kings Langley / Hemel) and see what you are receiving.
134 is very close to the frequency for the Dunstable transmitter (8.9miles North of Hemel), which is the most likely candidate for providing the TM TMC signal in that area. The Level is high enough that you should be getting a signal, and a mode 3 would indicate you are so close to actually receiving traffic messages!
Just to complete this, I have a Nuvi (310), with a GTM12, but I don't live that close to you, but do drive through that area on a fairly regular basis. _________________ Please don't be offended if I do not reply to a PM - please ask questions via the forums.
I live in Kings Langley and get good TMC reception around that area, also around the M25 towards Heathrow, but going the other direction on the M25 my experience has been that there is no signal between J.22 and J.20.
I came back from South Mimms last Sunday, and ended up in a queue just past J.21 all the way through to J.20. The TMC got a signal and decided to tell me about it just as I was exiting on the slip road to the A41.
I work in Garston and have also found that I never get a TMC signal when I leave work until I get to the bottom of Gallows Hill in Abbotts Langley (a few hunderd yards form Kings Langley railway station and virtually the same area as J.20
St. Albans area and the M1 south of J.6 seems pretty dead TMC wise in my experience.
Joined: Nov 04, 2003 Posts: 2225 Location: Bedfordshire, UK
Posted: Thu Aug 09, 2007 6:28 am Post subject: Re: But what does it Mean! GTM Status page
inspiredron wrote:
I, too, would like to know what the headings mean
CC - Country Code
SID - Station ID
LTN - No idea
However, SID and LTN are normally fixed across the particular TMC network, so as long as you are seeing the TM figures, and not the iTIS figures, you are fine
MODE - I think it's 2 is searching, 3 is locked on. No idea what 1 means.
N-SYNC - Not sure, and it's too early in the morning to go out and play with my GTM unit to confirm. 255 means no messages flowing though, anything less means messages are flowing. _________________ Please don't be offended if I do not reply to a PM - please ask questions via the forums.
I was expecting that around the M25 I would have "Full Coverage". Do you think this is a case of Misleading Advertising?
What do you all think to starting up a new group specifically for Good VS Bad TMC areas. It would have helped me make a more informed decision.[/quote]
Joined: Nov 04, 2003 Posts: 2225 Location: Bedfordshire, UK
Posted: Thu Aug 09, 2007 9:37 am Post subject: Re: False Advertising?
adrian_anastas wrote:
Before I purchased the GTM unit I checked the coverage area on the Garmin website:
There is a statement somewhere on their website along the lines of "traffic only available where there is coverage", but I agree the map implies a better service than you get. I suspect the map came from Trafficmaster, who are used to the idea of fully integrated SatNav units which will use the car's external aerial for their traffic feed. Even so, the map has not been updated to allow for the loss of the NW signal area, which is very wrong.
Quote:
Do you think this is a case of Misleading Advertising?
I think it's potentially grounds for getting your money back, but that won't improve the service...
Quote:
What do you all think to starting up a new group specifically for Good VS Bad TMC areas. It would have helped me make a more informed decision.
I did try this once, but the list became unworkable - however, back in those days the Garmin units were not performing to the best of their ability, which introduced lots of areas of the country where TMC was available (but the Garmin simply couldn't detect it), so maybe a list could be started.
For starters:
M25 North Western section (around to, and including parts of the M4 heading out of London, and the M3 heading out of London)
The North West of England (around Preston / Blackpool and North to the border)
Lincolnshire
Devon
Cornwall
Norfolk (apart from Norwich)
Salisbury area
Stoke-on-Trent area
Most of Yorkshire, except Leeds and Sheffield areas
Wales (apart from a couple of small areas)
Scotland (apart from a little coverage in Glasgow and Edinburgh)
The Cotswolds
Any hilly area
I'm kinda tempted to list the areas where it does work, it may be a shorter list ;)
I should add - some of those areas are based on personal experience, some on hearing reports from others, and some are based on studying a map of the TM transmitter sites and simply working out that it simply won't reach! _________________ Please don't be offended if I do not reply to a PM - please ask questions via the forums.
Joined: 14/09/2002 20:56:18 Posts: 5231 Location: Surrey, United Kingdom
Posted: Thu Aug 09, 2007 5:15 pm Post subject: Re: But what does it Mean! GTM Status page
swing wrote:
MODE - I think it's 2 is searching, 3 is locked on. No idea what 1 means.
Mine showed either 2 or 5 today. Reception was OK from Gatwick to the M11 near Bishop's Stortford. I lost it after leaving the M11. I was receiving data from four different frequencies, these being 102.7, 95.8, 106.2 and 101.7MHz. My TomTom kept reception for the most part on the journey, always on 100.9MHz. _________________ Tim
Posted: Fri Aug 10, 2007 12:21 am Post subject: Re: But what does it Mean! GTM Status page
Tim Buxton wrote:
I was receiving data from four different frequencies, these being 102.7, 95.8, 106.2 and 101.7MHz. My TomTom kept reception for the most part on the journey, always on 100.9MHz.
How do you know which frequency relates to each chanel? Is there a mapping for chanel 134 to a frequency?
Joined: 14/09/2002 20:56:18 Posts: 5231 Location: Surrey, United Kingdom
Posted: Fri Aug 10, 2007 5:26 am Post subject: Re: But what does it Mean! GTM Status page
adrian_anastas wrote:
How do you know which frequency relates to each chanel? Is there a mapping for chanel 134 to a frequency?
Apparently you add your 'channel' divided by 10 (in your case 13.4) to the base figure of 87.5 to get the station frequency, so yours would be 100.9MHz. _________________ Tim
Posted: Fri Aug 10, 2007 10:02 am Post subject: Re: But what does it Mean! GTM Status page
Tim Buxton wrote:
[Y]ours would be 100.9MHz.
Well **** me! That's Classic FM. From Swings comments earlier it does look like Mode 2 is locked on and mode 3 is searching, as when it sticks to 134 it changes to 2 (even in St Albans).
I never get any traffic messages though, so I might need to take a drive further towards Dunstable.
Is there anyone else out there in or around London that can give some feedback on what they are getting?
Joined: Jan 14, 2005 Posts: 19638 Location: Blackpool , Lancs
Posted: Fri Aug 10, 2007 3:47 pm Post subject:
Correct 100,9FM is the Classic FM transmision from the Wrotham Transmitter (250KW power so its got quite a range).
Location 51,320376N 0,291800E (you can even see this aerial using Google Earth).
You will not get any data from that station though as it transmits data provided by iTIS who supply Route 66 and TomTom with data.
Garmin use Traffic Master which is the other supplier of Traffic information and the two systems use different radio stations - the data is not the same so you can only use one - with Garmin its Taffic Master - Mike
Correct 100,9FM is the Classic FM transmision from the Wrotham Transmitter (250KW power so its got quite a range).
Location 51,320376N 0,291800E (you can even see this aerial using Google Earth).
You will not get any data from that station though as it transmits data provided by iTIS who supply Route 66 and TomTom with data.
Garmin use Traffic Master which is the other supplier of Traffic information and the two systems use different radio stations - the data is not the same so you can only use one - with Garmin its Taffic Master - Mike
I figured that from other threads. Which transmitters/radio stations transmit the Traffic Master information? I'm sure I read somewhere that this includes Chrysalis, Capital and another Station group, but I am unable to find any info on this.
I guess I'm trying to fugure out whether or not it's worth keeping the GTM 12. If there are no transmitters near where I travel I see no point.
Posted: Sat Aug 11, 2007 7:40 pm Post subject: Thanks!
Thanks Mike,
This shows that I live less than a mile from my closest transmitter (Alexandra Palace), and I drive past it every day on the way to work. I've been working in St Albans, so I'm close to the Dunstable transmitter.
Guess either my unit is faulty, or the latest Firmware has killed it. Either way it's going back to Garmin.
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