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Okay, here are some photographic examples of what I've been talking about - the direction flow in the main heading does not match the direction flow in the subheading. Apologies for the size of the photos.
The first example is of a traffic incident described as comprising Basingstoke to London:
In the picture above the traffic flow also does not agree in the Bracknell to Guildford incident.
The second example also described Basingstoke to London on a different day:
The third one describes Basingstok to Reading and Reading to Basingstoke with the same subheading message in both incidents:
I've come across many others but it just happens that most of the recent ones I've seen have included Basingstoke in the report!
Joined: Jan 04, 2007 Posts: 2789 Location: Hampshire, UK
Posted: Wed Apr 25, 2007 7:43 am Post subject:
Sallyann wrote:
In that case something must be wrong with it. Are you sure the amplified aerial is properly connected to the Mio? Which pin did you use and did you fit a DC blocking capacitor? Where was the screen of the aerial lead connected?
Sal,
Thanks for your input.
I checked the aerial with a meter and there was a direct contact between the 'amplified' feed and the correct pin on the 2.5mm jack.
There was no DC voltage between the 'amplified' feed and the ground shield - so I didn't see any need for a capacitor.
There was a direct contact between the aerial screen and the 'negative' feed to the circuit board, so connecting the positive and negative leads should have routed the screen to the correct 'source'.
I'm an electronics engineer and checked what I was doing with a couple of colleagues (because I'm not overly familiar with car circuitry) and we agreed that what I had done was correct.
Our suspicion is that the glass mount aerial was not picking up a sufficiently strong signal and, despite being amplified, was not up to the job - it was only £10 and viewed as an experiment.
Joined: Jan 04, 2007 Posts: 2789 Location: Hampshire, UK
Posted: Wed Apr 25, 2007 7:58 am Post subject:
Retty wrote:
Okay, here are some photographic examples of what I've been talking about - the direction flow in the main heading does not match the direction flow in the subheading. Apologies for the size of the photos.
Hi Retty,
Thanks for the photos.
If I remember correctly, one of your complaints was that the TMC information often contradicted the true direction of the problem - do you remember the true direction of the problems identified in your photos and whether the Mio identified this correctly or advised you of a jam on the opposite carriageway?
This information seems to have been omitted from your post.
As far as I understand TMC, the heading identifies the location and the subheading gives directional information in addition to pinpointing the location more precisely.
Like I've said before, there are only so many ways to identify a stretch of road and, using the example I gave previously, would you say that Fleet services is between J4A and J5 or J5 and J4A on the M3 when you're limited to a few characters of text?
Both TrafficMaster and iTIS seem to use similar text to identify the stretch of road and in both cases, it appears to be the sub-heading which pinpoints the problem and gives the directional information.
Joined: Jan 14, 2005 Posts: 19638 Location: Blackpool , Lancs
Posted: Wed Apr 25, 2007 7:58 am Post subject:
The amplified glass mount aerial is not too good to be honest, it needs the amplifier to extract any form of usable signal from a poor aerial.
You would be better off connecting the device to the vehicles exisiting aerial via a splitter, or consider fitting the amplifier from the glass mount in-line between the aerial and splitter to boost the signal level, site member "vicky" has done this very modification combined with a TomTom RDS-TMC unit see This page for some photos, the actual details are earlier in the thread - Mike
Okay, here are some photographic examples of what I've been talking about - the direction flow in the main heading does not match the direction flow in the subheading. Apologies for the size of the photos.
Hi Retty,
Thanks for the photos.
If I remember correctly, one of your complaints was that the TMC information often contradicted the true direction of the problem - do you remember the true direction of the problems identified in your photos and whether the Mio identified this correctly or advised you of a jam on the opposite carriageway?
This information seems to have been omitted from your post.
As far as I understand TMC, the heading identifies the location and the subheading gives directional information in addition to pinpointing the location more precisely.
Like I've said before, there are only so many ways to identify a stretch of road and, using the example I gave previously, would you say that Fleet services is between J4A and J5 or J5 and J4A on the M3 when you're limited to a few characters of text?
Both TrafficMaster and iTIS seem to use similar text to identify the stretch of road and in both cases, it appears to be the sub-heading which pinpoints the problem and gives the directional information.
On the first occasion the sub-heading was incorrect - the main heading correctly identified the carriage direction of the congestion. On the second occasion I was unable to see any congestion at all. The third example - albeit using journalistic information - shows that the subheading can be identical even when the main heading is describing both direction flows.
I'm not clear why you say that there's ambiguity when describing the relative junction positions of stretches of road. It isn't about there being a few characters of text. It simply depends on the direction of travel as to whether something is between junction 3 and junction 4a or between junction 4a and junction 3. This is exactly the method that the C710 uses (very well) when describing jams on right hand side drive roads (in Belgium for example). It sometimes works correctly here also.
My understanding is that the TMC broadcast provides location table type data that is linked with the map on the device. Whether or not the problem is connected with the transmission data or with the Mio's interpretation of it is beyond me.
Yesterday I was caught in a jam which the Mio described as being on the opposite side of the road - in this case the main heading was wrong and the subheading would have been correct. The Mio appeared to use the incorrect main heading information. The information on the map clearly showed the jam on the wrong carriageway. The information was quite precise with the blue line describing the actual point to point location of the jam - but on the wrong carriageway.
I should emphasise again that these problems do not impact my use of TMC in continental Europe.
There is a problem with Mio TMC when describing some traffic incidents on left hand side drive roads in the UK.
Joined: Jan 04, 2007 Posts: 2789 Location: Hampshire, UK
Posted: Wed Apr 25, 2007 2:35 pm Post subject:
I'm only going by my own experience, where the sub-heading information has ALWAYS agreed with radio traffic bulletins and traffic flow (or lack thereof).
Perhaps you're right, Retty, but trying to find any kind of information regading TMC and how it should work is like looking for rocking horse dung or hens' teeth - nigh on impossible.
If, as you say, TMC uses a location table linked to the map and bearing in mind that the Mio CORRECTLY navigates on the left hand side of the road, I fail to understand why TMC should suddenly mysteriously jump to the opposite carriageway - have you ever been navigated down the wrong side of dual carriageway or motorway?
I'm only going by my own experience, where the sub-heading information has ALWAYS agreed with radio traffic bulletins and traffic flow (or lack thereof).
Perhaps you're right, Retty, but trying to find any kind of information regading TMC and how it should work is like looking for rocking horse dung or hens' teeth - nigh on impossible.
If, as you say, TMC uses a location table linked to the map and bearing in mind that the Mio CORRECTLY navigates on the left hand side of the road, I fail to understand why TMC should suddenly mysteriously jump to the opposite carriageway - have you ever been navigated down the wrong side of dual carriageway or motorway?
The subheading information details the precise location of the jam. Yet the main heading more often than not describes the correct flow direction of the jam even when the flow direction in the subheading is incorrect.
If you imagine that the UK is a right hand carriageway drive country then both headings would agree in terms of flow direction.
Is it simply a case that as a result of a bug or an oversight in Mio software an incorrect assumption is made that the UK is a right hand drive country?
Other devices that use ITIS messages - such as AA Navigator and the AA online Roadwatch service - don't have the same problem as the C710.
At risk of being a dog with an old bone I'm actually trying to be helpful and, so far, I've failed dismally to persuade Mitadc to even acknowledge that there is a problem impacting UK users of the C710 in terms of TMC reporting. The problem does *not* impact continental European use of the C710 and I can say from experience that the direction flow in main heading and subheading does match there. It's frustrating because if the problem is down to a bug in the C710 software it could, no dount, be easily corrected.
Joined: Jan 04, 2007 Posts: 2789 Location: Hampshire, UK
Posted: Wed Apr 25, 2007 7:27 pm Post subject:
I'm NOT saying you're wrong, I'm just saying that I haven't experienced this phenomenon myself...
...and I have great difficulty understanding why you're blaming driving on the left for directional information, which is only intermittently wrong - if the traffic flow was always given in the wrong direction, then it would be much easier to understand.
I keep an eye on TMC and an ear tuned into radio bulletins, but (thus far) they have always agreed.
Sorry for being such a dummy...
...but if it really is a problem, then you're right to be a dog with an old bone!!
Joined: Jan 04, 2007 Posts: 2789 Location: Hampshire, UK
Posted: Wed Apr 25, 2007 8:58 pm Post subject:
Oh yes, a perfect example of what I was trying to say about identifying the location, direction and so on happened today when the A3 was closed in both directions:
Heading - South Guildford - Liss
Sub-heading - Guildford - Hindhead
Distance - 28 miles
Heading - South Guildford - Liss
Sub-heading - Hindhead - Liphook
Distance - 24 miles
Hence this supports my thinking of:
heading = location
sub-heading = direction
...I did try to take a screen shot of this, but the only camera I had on me at the time was the camera on my phone and the pictures were worse than useless
I'm NOT saying you're wrong, I'm just saying that I haven't experienced this phenomenon myself...
...and I have great difficulty understanding why you're blaming driving on the left for directional information, which is only intermittently wrong - if the traffic flow was always given in the wrong direction, then it would be much easier to understand.
I keep an eye on TMC and an ear tuned into radio bulletins, but (thus far) they have always agreed.
Sorry for being such a dummy...
...but if it really is a problem, then you're right to be a dog with an old bone!!
Okay, I've tried my best - even including photographic proof of the problem - and now I have to admit defeat in the face of arguments that either deny the existence of a problem or reframe it in terms of main heading describing "location" and sub-heading describing direction flow :-) I agree with you that "blaming" it on a left side drive bug is problematic given that the problem is intermittent but rather than "blaming" a left side driving bug I'm merely trying to suggest a possible explanation for a problem that doesn't seem to exist when the Mio processes continental TMC.
For what it's worth my experience is this: sub-heading does not describe the direction flow - almost always it is the main heading that describes the correct direction flow and although there are cases where the main heading is wrong and the sub-heading is correct in these cases the jam is then reported as being on the incorrect side of the road.
I'm tempted to provide yet more photographic evidence when I go to the continent in a week or so but, to be honest, I'm tempted to give up...
Joined: Jan 04, 2007 Posts: 2789 Location: Hampshire, UK
Posted: Thu Apr 26, 2007 8:01 am Post subject:
Retty,
I don't mean to sound as though I'm simply dsmissing what you're saying - it just doesn't make sense to me why it only happens occasionally.
Is it possible that iTIS and/or TrafficMaster occasionally transmit data containing incorrect information which confuses the GPS?
Other GPS manufacturers use Tele Atlas maps.
The Mio consistently navigates you along the correct carriageway.
Do you know how TT or ANOther GPS behaves in that location and receiving the same TMC data?
Your Mio is receiving TMC data from a third party and has no control over its content or accuracy.
Radio stations use traffic information, but they have the benefit of human integration to ensure its accuracy prior to broadcasting to the public.
Have you ever had the benefit of a radio traffic bulletin (or other backup source) when you've experienced this phenomenon?
This morning, there were problems on the M3 and my unit correctly identified location and direction.
A big part of this problem is the lack of useful information regarding TMC:
exactly how is the data obtained?
how is the data processed?
how is the data transmitted?
how does the GPS handle the data?
does the GPS do any TMC processing or does it simply display what it receives?
what algorithms does the GPS use to re-route around a perceived problem?
It's all too easy to blame the Mio because that's what you're looking at, but there's a lot going on behind the scenes and involving third parties, which Mio and the GPS has absolutely no control over.
For example, is it always Microsoft or the PC manufacturer's fault if your computer gets a virus or does the fault lie elsewhere - receiving a 'contaminated' e-mail, opening a 'contaminated' attachment etc.
Where does the responsibility of the PC manufacturer end and third parties become responsible?
I think GPS-fan has summed this up pretty well.
The Mio is a mass-produced consumer item, and for the low cost it does a remarkably good job.
The GPS service is free to use (after presumably paying a small fee included in the hardware purchase cost).
It's tempting to expect more facilities, better accuracy and comstant updates, but in the real commercial world that's not going to happen.
Personally I'm happy to just use it as a tiny but valuable adjunct to a busy life, without constantly analysing it and wanting something more.
Others may feel different of course, and I don't intend this as a personal criticism
I checked the aerial with a meter and there was a direct contact between the 'amplified' feed and the correct pin on the 2.5mm jack.
There was no DC voltage between the 'amplified' feed and the ground shield - so I didn't see any need for a capacitor.
There was a direct contact between the aerial screen and the 'negative' feed to the circuit board, so connecting the positive and negative leads should have routed the screen to the correct 'source'.
I'm an electronics engineer and checked what I was doing with a couple of colleagues (because I'm not overly familiar with car circuitry) and we agreed that what I had done was correct.
Our suspicion is that the glass mount aerial was not picking up a sufficiently strong signal and, despite being amplified, was not up to the job - it was only £10 and viewed as an experiment.
The next step is to try a better aerial feed
It certainly seems you have done all the right things!
Joined: Jan 04, 2007 Posts: 2789 Location: Hampshire, UK
Posted: Thu Apr 26, 2007 10:09 am Post subject:
Sallyann wrote:
I think GPS-fan has summed this up pretty well.
The Mio is a mass-produced consumer item, and for the low cost it does a remarkably good job.
The GPS service is free to use (after presumably paying a small fee included in the hardware purchase cost).
It's tempting to expect more facilities, better accuracy and comstant updates, but in the real commercial world that's not going to happen.
Personally I'm happy to just use it as a tiny but valuable adjunct to a busy life, without constantly analysing it and wanting something more.
Others may feel different of course, and I don't intend this as a personal criticism
Sal
Sal,
Yes, I think I've mentioned before that we're no longer satisfied with our GPS simply guiding us to our destination - the more a GPS does, the less satisfied we appear to be with it.
I must admit that TMC was something I hadn't really heard about until I downloaded the full version of the Mio user manual and now I kind of expect it to guide me around the queue behind that tractor in front of me sort of thing.
In my experience, it has successfully re-routed me around problems and in that respect I'm happy.
However, I'm not too pleased about the poor reception - my daily commute to/from work has TMC reception for less than 50% of the journey, hence my desire to resolve this issue.
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