Mounting a transponder

Mounting a transponder

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Discussion

nate-dogg

Original Poster:

26 posts

14 months

Saturday 16th March 2019
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Another daft question from a racing newbie this year... where are you supposed to mount a transponder? The My Laps manual says in the wheel arch, but I’m concerned about it catching/rubbing... Am I being thick and there’s somewhere much better to mount it?

Would appreciate a nudge in the right direction!

ginettajoe

2,020 posts

168 months

Saturday 16th March 2019
quotequote all
nate-dogg said:
Another daft question from a racing newbie this year... where are you supposed to mount a transponder? The My Laps manual says in the wheel arch, but I’m concerned about it catching/rubbing... Am I being thick and there’s somewhere much better to mount it?

Would appreciate a nudge in the right direction!
Mount it as near to the front of the car, inside the engine bay, with a clear space between the transponder and the tarmac, usually on the inner wing, or chassis member. Avoid placing it where it could suffer damage in a light or heavy impact. HTH

Kraken

1,322 posts

150 months

Saturday 16th March 2019
quotequote all
Inside of one of the chassis legs just behind the front cross member is where I've always put mine with no issues.

ChevronB19

1,265 posts

113 months

Saturday 16th March 2019
quotequote all
You can pretty much mount it anywhere so long as it’s reasonably close to the ground.

On my 105e Anglia it’s inside the car, tie wrapped to the front near side roll cage leg, same as most competitors in the series. Never had a problem with scrutineers or with sensors picking it up.

Order66

6,136 posts

199 months

Saturday 16th March 2019
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Check your series regs - some specify where it has to be, but generally if front wheel arch

nate-dogg

Original Poster:

26 posts

14 months

Sunday 17th March 2019
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Thanks all. I’ve discovered a mysterious cable with nothing on the end of it leading to the wheel arch, which I now assume is for a transponder. I shall put it there I think!

Robmarriott

1,945 posts

108 months

Monday 18th March 2019
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What car is it?

On my old Clio I mounted it on the panel behind the side of the front bumper, no chance of it catching there.

nate-dogg

Original Poster:

26 posts

14 months

Friday 22nd March 2019
quotequote all
Robmarriott said:
What car is it?

On my old Clio I mounted it on the panel behind the side of the front bumper, no chance of it catching there.
Mini Cooper S R53.

sabid

69 posts

121 months

Friday 26th April 2019
quotequote all
nate-dogg said:
Another daft question from a racing newbie this year... where are you supposed to mount a transponder? The My Laps manual says in the wheel arch, but I’m concerned about it catching/rubbing... Am I being thick and there’s somewhere much better to mount it?

Would appreciate a nudge in the right direction!
If you found the cable then I'm sure you've got this positioning sorted. In case you haven't then it is worth being aware that whilst many people will say it doesn't matter, it can be important.

For pure laptime it makes no difference where you put the transponder. In a race though it is different.

If you are in a drag to the line, it is who's transponder reaches the line first will determine the place - too far back could cost you a place(s)

Yes, if you are out front for the win then this is normally declared visually but it would be gutting to miss out on a win that way and either way, it is rubbish thing to go through whilst someone subjectively decides the positions ...

Depending on your race cars speed across the line, the position of the transponder can therefore be more important than many people think - the slower you cross the line the more this is important.

Equally, as has been said and as you suspect, putting the transponder out front in a vulnerable position is quite risky!

With a bit of maths you can work out how far back will start to make a difference. We had this same question come up on another forum recently so I put this short article together to help.

https://www.yourdatadriven.com/where-is-the-best-p...

Put simply, if you cross the line at 100 mph then the you can put the transponder anywhere in the first 20 cm behind front of the car without risk of loosing out in a drag race over the line.

At lower speeds this distance reduces so it might be worth knowing the exact trade off you are making, if that is getting too close to a vulnerable position.

You can quantify this exactly, per above, so thought I'd share as it is not often people really think this through.

Best of luck with the racing!

ginettajoe

2,020 posts

168 months

Saturday 27th April 2019
quotequote all
sabid said:
nate-dogg said:
Another daft question from a racing newbie this year... where are you supposed to mount a transponder? The My Laps manual says in the wheel arch, but I’m concerned about it catching/rubbing... Am I being thick and there’s somewhere much better to mount it?

Would appreciate a nudge in the right direction!
If you found the cable then I'm sure you've got this positioning sorted. In case you haven't then it is worth being aware that whilst many people will say it doesn't matter, it can be important.

For pure laptime it makes no difference where you put the transponder. In a race though it is different.

If you are in a drag to the line, it is who's transponder reaches the line first will determine the place - too far back could cost you a place(s)

Yes, if you are out front for the win then this is normally declared visually but it would be gutting to miss out on a win that way and either way, it is rubbish thing to go through whilst someone subjectively decides the positions ...

Depending on your race cars speed across the line, the position of the transponder can therefore be more important than many people think - the slower you cross the line the more this is important.

Equally, as has been said and as you suspect, putting the transponder out front in a vulnerable position is quite risky!

With a bit of maths you can work out how far back will start to make a difference. We had this same question come up on another forum recently so I put this short article together to help.

https://www.yourdatadriven.com/where-is-the-best-p...

Put simply, if you cross the line at 100 mph then the you can put the transponder anywhere in the first 20 cm behind front of the car without risk of loosing out in a drag race over the line.

At lower speeds this distance reduces so it might be worth knowing the exact trade off you are making, if that is getting too close to a vulnerable position.

You can quantify this exactly, per above, so thought I'd share as it is not often people really think this through.

Best of luck with the racing!
..... yes, you are correct, and the reason I stated to fit it as close to the front of the car, but without explanation, which you kindly fulfilled!! beer

sabid

69 posts

121 months

Monday 29th April 2019
quotequote all
ginettajoe said:
..... yes, you are correct, and the reason I stated to fit it as close to the front of the car, but without explanation, which you kindly fulfilled!! beer
beer

MyVTECGoesBwaaah

712 posts

92 months

Monday 29th April 2019
quotequote all
Don't forget to have it on the right plane/angle too thumbup

BertBert

13,370 posts

161 months

Monday 29th April 2019
quotequote all
sabid said:
ginettajoe said:
..... yes, you are correct, and the reason I stated to fit it as close to the front of the car, but without explanation, which you kindly fulfilled!! beer
beer
Except that the website is sadly wrong rolleyes
It's 44.704, not 44.4
Timing is done to 1/1000th second not 1/100 (well when TSL do it anyways)
1/1000 second is about 2cm at 100mph.
(the ever helpful) Bert

BertBert

13,370 posts

161 months

Tuesday 30th April 2019
quotequote all
On the subject, I am intrigued by how the transponder works with a detection loop. I don't even know whether it's electromagnetic,RF or IR (it's not the latter though). I can't really figure out using my schoolboy physics how it might work. It must encode the transponder number into an analogue signal and the receiver somehow has to decide when the transponder goes over the detection loop. It's not going to be a directional signal, so does it detect the point of maximum strength to be the point where the transponder is over the detector?

Not sure it's going to help me drive faster though!

Bert

majordad

3,233 posts

147 months

Tuesday 30th April 2019
quotequote all
Does the signal from the loop come from under the track? Or is it to the side, either left or right?

BertBert

13,370 posts

161 months

Tuesday 30th April 2019
quotequote all
The one picture I found with googling showed the 'loop' under the track. That makes the required working range of the transponder to be a few feet rather than a track width (or half a width).
Bert

MyVTECGoesBwaaah

712 posts

92 months

Tuesday 30th April 2019
quotequote all
The loop is under the track, you can often see where the track has been cut to lay it.

The transponder signal is picked up many times as you cross over the loop, the time comes from when you break the beam.

BertBert

13,370 posts

161 months

Tuesday 30th April 2019
quotequote all
MyVTECGoesBwaaah said:
The loop is under the track, you can often see where the track has been cut to lay it.

The transponder signal is picked up many times as you cross over the loop, the time comes from when you break the beam.
Which would make a complete nonsense of the whole - where to place your transponder question. However I am 99% certain that there is no 'beam'!
Bert

MyVTECGoesBwaaah

712 posts

92 months

Wednesday 1st May 2019
quotequote all
BertBert said:
MyVTECGoesBwaaah said:
The loop is under the track, you can often see where the track has been cut to lay it.

The transponder signal is picked up many times as you cross over the loop, the time comes from when you break the beam.
Which would make a complete nonsense of the whole - where to place your transponder question. However I am 99% certain that there is no 'beam'!
Bert
A beam is used, it may be a bit hidden at some circuits due to their setup but somewhere like Croft for example you can see on side on a tripod in the infield near the start/finish line.

There is no beam for the other loops like sectors or pits however.

Kraken

1,322 posts

150 months

Wednesday 1st May 2019
quotequote all
Beam timing systems and the AMB transponders are two different things.