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torchie Occasional Visitor
Joined: Mar 04, 2006 Posts: 9
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Posted: Sat Oct 28, 2006 8:42 pm Post subject: |
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Thanks Mike, unfortunately Craigkelly & Blackhill are out of range, I drive past the Angus TX every day so looks like Classic Fm are not transmitting
TMC for Trafficmaster-Ron |
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see-ell Occasional Visitor
Joined: Oct 04, 2006 Posts: 13 Location: Suffolk, UK
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Posted: Sun Oct 29, 2006 2:12 pm Post subject: |
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I believe another method to establish the frequency of a TMC channel is to multiply channel number by 0.1 and then add 87.5.
eg Ch155 equates to 155 * 0.1 = 15.5 then add 87.5 resulting in 103.0 which happens to be one of the few channels I can receive reliably around Cambridge !! ie Q103. I also find Traffic reception patchy even in what should be areas of good reception eg around Northern sections of the M25!!
As I understand it, RAC Trafficmaster (as used by Garmin) only uses radio stations from GCap Media and Chrysalis Radio. Thus the reason why the Garmin TMC may lock on to Classic FM frequencies, but not receive any Traffic updates.
Note that I have also tried the TMC solution from AA/Evesham as supplied with the Nav-Cam 7500 with even worse results than the Garmin. At least the data from RAC/Trafficmaster seems to be more up to date and reliable than that from ITIS and broadcast on Classic FM stations.
As other contributors have mentioned, the problem with reliable reception of TMC reception is mainly due to low power local radio transmitters broadcasting TMC coupled with trying to receive these signals on 'wet string' antennas mounted inside vehicles.
It just seems a shame that TMC data is not broadcast on BBC FM frequencies
Chris |
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mikealder Pocket GPS Moderator
Joined: Jan 14, 2005 Posts: 19638 Location: Blackpool , Lancs
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Posted: Sun Oct 29, 2006 4:49 pm Post subject: |
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see-ell wrote: | I believe another method to establish the frequency of a TMC channel is to multiply channel number by 0.1 and then add 87.5. | Thanks for that Chris, much appreciated, the reason I asked about Classic was not just the receiver looking at that frequency but the owner is GCAP, I guess they don't transmit both TM and iTIS on the same frequency though!
To be honest the issue about transmitter power levels leads me to believe Garmin have done a credible job with the receiver, the stations that TM uses are very low in power. I will finish off the transmitter POI file later tonight now I know the channel numbers.
As for the BBC, I guess its down to price but I agree their transmitter network would be more resilient across the country, I suppose the next best thing would be for someone to start using a DAB broadcast for TMC, but I bet that’s a few years off from now- Mike |
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see-ell Occasional Visitor
Joined: Oct 04, 2006 Posts: 13 Location: Suffolk, UK
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Posted: Sun Oct 29, 2006 5:52 pm Post subject: |
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Hi Mike,
Maybe it is not technically feasible to transmit both providers TMC on the same transmitter? I'm not too sure.
Yes, I agree with you re. Garmin traffic receiver. I guess it is unreasonable to expect good reception from low power transmitters on a piece of 'wet string'. Therefore the only real answer is to use an amplified external antenna but still expect areas of poor reception. Not so good though for those of us that want a portable solution. Its a shame though, because Sat Nav in cars becomes REALLY useful when it has the capability to re-route around traffic jams. But for that to be effective, then TMC has got to be timely, reliable and capable of being received across the bulk of the UK road network.
Oh well, I guess its back to listening out for Sally Traffic
Have fun with the POI's
Chris |
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mikealder Pocket GPS Moderator
Joined: Jan 14, 2005 Posts: 19638 Location: Blackpool , Lancs
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Posted: Sun Oct 29, 2006 10:34 pm Post subject: |
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I now have a Garmin compatible POI file for the transmitter towers used for TrafficMaster data throughout the UK. Should anyone want a copy please use my e-mail button below and I will reply with the csv and corresponding bmp file.
In use the POI file can be used to establish distance to the transmitter your unit is using, it can't improve the reception but for interest value at least you will know the distance and transmitter power level plus the channel number.
Thanks again to See-ell for the final "Jigsaw piece"
On the display you will see the transmitter station name followed by two numbers in brackets, the first is the Garmin channel number, the second is the transmitter’s power in KW. Where the transmitters name is too long simply select the the POI to display the full details.
I have included all the Radio stations allied to GCAP Media and Chrysalis although I doubt some of the smaller stations transmit TMC data their output is less than some domestic light bulbs! - Mike |
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parbrook Occasional Visitor
Joined: Jun 08, 2006 Posts: 42
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Posted: Mon Oct 30, 2006 10:24 am Post subject: |
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mikealder wrote: | I suppose the next best thing would be for someone to start using a DAB broadcast for TMC, but I bet that’s a few years off from now- Mike |
Don't be surprised if at least one DAB TMC trial appears in the UK during 2007.
TMC is already supported in the DAB specifications. |
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swing Pocket GPS Verifier
Joined: Nov 04, 2003 Posts: 2225 Location: Bedfordshire, UK
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Posted: Mon Oct 30, 2006 1:34 pm Post subject: |
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see-ell wrote: | Thus the reason why the Garmin TMC may lock on to Classic FM frequencies, but not receive any Traffic updates. | Although it used to with earlier GTM firmwares, I find it rare that my unit locks onto Classic FM at all (the only time I've really seen it is straight after wiping all the FM table information) - Once it's built up a little data, it seems to steer well clear of Classic FM, which is good (and what one would expect to happen). |
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pandamedic Occasional Visitor
Joined: Oct 25, 2004 Posts: 50
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Posted: Tue Oct 31, 2006 1:08 pm Post subject: |
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can someone tell me how you know how good the traffic recption is on the 310D and how you go about it. I know you touch the top left cornor for the sats, but dont know about the traffic one |
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capsecum Occasional Visitor
Joined: Jul 24, 2006 Posts: 18 Location: Lincolnshire, UK
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Posted: Tue Oct 31, 2006 2:55 pm Post subject: |
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Got to the map page push on the bottom left of the screen [speed or Arrival time] to get to the statistics page. Now hold your finger on the Moving AVG for 8-10 seconds. This will bring up a new screen push next repeatedly until you get to the GTM Status Page. Channel, Signal Level etc can be seen here. Pushing next again will take you to the FM Table. |
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BAVC10 Lifetime Member
Joined: Dec 20, 2005 Posts: 753
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Posted: Wed Nov 01, 2006 12:51 pm Post subject: |
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I've just received a new in-car charger from Garmin this morning. The model number ends in 6025 and according to the note is the latest model they produce. I don't know how Pandemic received one ending 022455.
Has anyone else been sent 022455 recently and does it work better than 6025? |
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nicster Occasional Visitor
Joined: Sep 21, 2006 Posts: 1 Location: watford
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Posted: Wed Nov 01, 2006 4:50 pm Post subject: rubish traffic news |
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I bought a nuvi 310D form hafords as they told me that i didn't need traffic subscription just the stuf in the box the traffic attener only ever works when it feels like it which is very very rare!! i called garmin and they said it was fine in europe just not too good in the uk, Great!!
that was just what i wanted to here after spending 400 quid
still haven't managed to get a accurate speed cam software loaded
but still trying |
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Harveyc Occasional Visitor
Joined: Oct 23, 2006 Posts: 31 Location: Nr. Emsworth
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Posted: Wed Nov 01, 2006 6:42 pm Post subject: |
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You're in a strong position as the 310D was a specific TMC bundle. Do what somebody else here did recently, just bring it back, tell them it's not fit for purpose and get a 660 for the same price. IME this unit picks up pages of traffic, though the furthest north I've been with it is Luton from the south coast, but still loads of info and a very good avoidance route.
It also comes with 90day speedcam trial which again seems to be very accurate. I haven't tried the PGPSW one yet but it gets very good reports. |
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swing Pocket GPS Verifier
Joined: Nov 04, 2003 Posts: 2225 Location: Bedfordshire, UK
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Posted: Thu Nov 02, 2006 9:44 am Post subject: |
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Harveyc wrote: | It also comes with 90day speedcam trial which again seems to be very accurate. I haven't tried the PGPSW one yet but it gets very good reports. | You can also get a 90 day speedcam trial for the 3x0 Nuvi models (for those who don't change for the 660). |
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etaf Occasional Visitor
Joined: Oct 30, 2006 Posts: 29
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Posted: Thu Nov 02, 2006 11:39 pm Post subject: |
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i just purchased a Nuvi 310 and not happy with the unit traffic info
I have a freeway traffic master and it picks signals up all the time
talked to garmin and they suggest i put the aerial out the window and see what happens - and purchase a unit with a connection to the Radio
anyway this morning the temp was -0.5C and the powersupply did not come on until it was warm - so I called again and they are sending a replacement - hopefully that will fix it - if not perhaps i should have got a 660
i went in for a TomTom One @ £199
but walked out £100 quid lighter
£299
not happy really...
the power supply ends 6017 and has a green led when nothing connected and red when comnected |
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mikealder Pocket GPS Moderator
Joined: Jan 14, 2005 Posts: 19638 Location: Blackpool , Lancs
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Posted: Thu Nov 02, 2006 11:53 pm Post subject: |
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You should notice an improvement with the replacement charger lead look for the part number ending in 6025 when it arrives, a lot of the early problems with the Garmin TMC were to do with the PSU and noise, the newer charger seems to work much better, although reception is dependent upon the signal level within your area - this is variable accross the country - Mike |
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