720t Problems again

volkswarren · Lifetime Member Joined: Jan 20, 2007 Posts: 28

My 720t is giving me grief again, does anyone have problems with the traffic system between M5 junc 4 and M5 junc 15

My Tomtom will pick up traffic just about outside my house but by the time i have done 7 miles to get to junc 4 on the m5 my traffic signal has gone off and it doesn't come back on until bristol.

It seems to make no difference if the tmc wire is accross the bottom of the screen or up the side and over the top.

I have ver 13 and ver 14(usb) leads and to be honest the ver 13 gets the best signal.

It's really at the stage now where I need to upgrade to hd traffic as the tmc leads are no good for me.

We have 5 tomtom x20's in my immediate family and I have used other units in my 2 cars and both leads in my A6 and My Golf no really any joy with either. yet when I swap leads with my brother or sister my leads work with there tomtoms, though they don't drive on the m5.

As I am travelling to Yeovilton I need something to work on the m5. Is any one else having problems in this area?

Or anyone having no problems in this area?

Tomtom have given me an rma number to return my unit and tmc but as they work elsewhere I'm not sure they are at fault.

It worked perfectly last year when I 1st had the unit. Sad

DennisN · Posted: Fri Apr 03, 2009 11:39 pm Post subject:

Are you up against the athermic windscreen problem? Although that doesn't seem likely if you had it working at some time in the past.

I get no problem on M5 (other than that I don't trust Traffic implicitly) and journeys up to Birmingham get satisfactory signal coverage.

Are you running the antenna too close to the metalwork? This old photo layout was successful for me - TT in front of the steering wheel, antenna running across to centre then vertically up the centre of the windscreen. But I've changed it now to TT in centre of screen, antenna running across the bottom to bottom left, then vertically up to top of screen, a good three inches away from the screen frame. In both positions, I have had no vision problems, the antenna being thin enough to be almost invisible when I'm (or passenger is) looking ahead. (The aerial works with any of all three devices by the way).

_________________
Dennis

If it tastes good - it's fattening.

Two of them are obesiting!!

volkswarren · Lifetime Member Joined: Jan 20, 2007 Posts: 28

Cables are about 10-15 cm away from the metal though they were closer, I will try up the centre as your figure Smile

mikealder · Posted: Sat Apr 04, 2009 4:30 pm Post subject:

Routing the aerial wire in the way Dennis has shown tends to offer the best results from what I have tried, I also knott the aerial wire around the rear view mirror support arm as this secures it preventing it from falling off the little glass suckers - Mike

AndyVaughan · Posted: Sat Apr 04, 2009 5:28 pm Post subject:

I have spent the last couple of days in the Bristol area - I had no problems at all with RDS-TMC. Had a signal all the time, in fact I had a signal all the way from Rossendale to Bristol, there and back.

BUT - mine is wired to the cars amplified antenna. I am using the USB version on a 920.

Andy

volkswarren · Lifetime Member Joined: Jan 20, 2007 Posts: 28

is there a guide on connecting it to the ariel?

AndyVaughan · Posted: Sun Apr 05, 2009 6:57 pm Post subject:

There was a year or two ago on here - not difficult to do if you are handy with a solderng iron but you need to ensure that your car aerial feed does not have any DC voltage on it or you will fry the TMC receiver, and possibly damage the TT as well. If in doubt, try a second aerial just for the TMC.

Andy

volkswarren · Lifetime Member Joined: Jan 20, 2007 Posts: 28

I have an unused car phone aerial would that be any good?

mikealder · Posted: Sun Apr 05, 2009 9:22 pm Post subject:

The phone aerial is desinged to work in a different frequency band to the RDS receiver, the best approach is to connect the receivers aerial wire directly to the car aerial.
Just in case the car aerial is amplified and fed with 5 or 12 volts from the car deck fit a small value ceremic capacitor in series between the receiver and the car aerial cable, this blocks the DC voltage from damaging the receiver, but allows the FM signal through.
If you know the car aerial isn't amplified or fed by a voltage from the deck a simple Y piece splitter cable is all that is needed - Mike

volkswarren · Lifetime Member Joined: Jan 20, 2007 Posts: 28

Ok It's an Audi I know it's amplified so I'll get the bits from maplins to do it, glad it's a bank holiday Smile

AndyVaughan · Posted: Mon Apr 06, 2009 8:48 pm Post subject:

Watch out for earth loops as well - might be worthwhile trying not connecting the screen on the coax of the aerial cable to the earth on the TMC receiver. If it doesn't get a decent signal then solder it and see if it improves.

Andy

volkswarren · Lifetime Member Joined: Jan 20, 2007 Posts: 28

I'll have a better look this weekend, I changed to the up middle of the screen position and I had signal down to jnc 7 then nothing until junc 13, which was loads better than it's been recently but still poo.

DennisN · Posted: Mon Apr 06, 2009 9:08 pm Post subject:

With my present layout, still L shape, but bottom centre to bottom left, then up to top left, 2 to 4 inches from frame, I went today from Bristol up to M42, M6, M1, Northampton, back via Leamington Spa, Fosseway and Cirencester and never lost signal all the way. I can't remember the last time I lost signal and I travel wherever they send me.
_________________
Dennis

If it tastes good - it's fattening.

Two of them are obesiting!!

mikealder · Posted: Mon Apr 06, 2009 9:11 pm Post subject:

I will be kitting out a different vehicle with this modification as well as a few other little alterations I am making to it this weekend, so I should have a guide complete with pictures available by Saturday night if thats any help. It will use Maplins components as they are the very close to my home location, so links to the various components used will be included - Mike

AndyVaughan · Posted: Mon Apr 06, 2009 9:16 pm Post subject:

New car or a new sideline in TMC installations? Laughing

Andy

	PocketGPS
	Web