Weak AMB Transponder Signal

[RussMcB]

The last 2-3 events I've been told that my transponder signal is weak. I've checked the mount and it seems fine. It is mounted in my aluminum nose box and pointing through a 1" hole about 2" above the road surface. It is hard wired. I suppose something may be causing it to get less that 12-13 volts.

It's about 5 years old. They're pretty expensive, so I don't want to buy a new one.

Any thoughts or suggestions?

Maybe I can ask the T&S folks if they have a way to test them ...

TIA.

[JHaydon]

Most tracks have a test loop, but they're tough to use with hard-wired units. AMB can test and repair them -- for a fee, of course, but still cheaper than replacing.

How are the power and ground connections?

[Steve Demeter]

Is anything different about the mounting, hole size, ect now versus when the signal was not weak?

That is the first thing I would look for.

[Ken Lawrence]

I had mine mounted in the nose box with a 2-1/2" hole and never got a good signal. Moved it to the outside of box and all was well.

[RussMcB]

Most tracks have a test loop, but they're tough to use with hard-wired units. AMB can test and repair them -- for a fee, of course, but still cheaper than replacing.

How are the power and ground connections?

The first car that used it had it mounted on the outside of the tub. This is the first car I've had it mounted in the nose.

Thanks (everyone) for the suggestions. Sounds like I may need to find a better location, plus make sure the power & ground are good.

[Charles Warner]

Russ,

At the last RA event I attended I was told my transponder wasn't up to snuff. Same mounting and hole from day 1 which had always worked perfectly. After opening up the hole (through plywood undertray) it seemed to work OK. The T&S people said they had many examples of this problem as the transponders get over 4 years old. Mine is also hard wired and I was told this was not a factor. It seems there is a shelf life on these beasties that runs somewhere around 4-5 years. It was suggested I contact AMB - I haven't yet.

[Frank Williamson]

When I bought my car it did not have a transponder with it, so I bought a new one. I was told to just mount it pointing down right through the the floor and it would work fine. It is mounted sitting right against the steel pan, no hole, and picks up just fine even with the jabrock. It has always worked, no problems. So I would think location is not your problem.

Frank Williamson

[Mike Kolthoff]

Russ,

This has happened to me several times. Enlarge the hole(mine is through a crush box of a DB6) and fabricate a bracket about 20 degrees forward of true plumb (90degrees) this helped me reduce the number "low hits" My unit had this problem after several repaving jobs at the track. My transponder is as old as the first year they required it???? Since the change it has only been a couple of times it was an issue.

This condition happened every other weekend until I made my change...actually John Taylor made the suggestion so I cannot take credit for it.

[Purple Frog]

No one has mentioned it yet, but I think your problem is that your transponder is too close to the track. It broadcasts a cone shape signal. The higher the transponder the larger the pattern it broadcasts onto the track surface. Raise it to 4 or 5 inches and you will probably double the size of the pattern hitting the surface. At 100 mph it does matter. Of course if you raise it within the nose box, the hole in the bottom of the box has to be enlarged. It's more important how long the contact patch is front to rear, than left to right.

Get too high, say 24", and the signal strength gets too weak.

I got tired of fighting wizzy neat hidden locations. After I mounted mine outside the car, about 8" up, I have not had a problem. Ugly and not real aerodynamic. But it is easy to glance at it and see that it's working.

With the repaving of Road Atlanta and Roebling Road, i believe they did not raise the loops. So transponders that were just barely working before repaving, may not cut it after repaving.

[rickb99]

It is hard wired. I suppose something may be causing it to get less that 12-13 volts.

Sure could. Clean up the terminal contact points. Make sure none of the wires at the terminals or splices have any frayed or broken strands of wire. Turn on the transponder with the car running and measure the voltage right on the wires at the connection points. If the voltage is low, you might have a wire problem back beyond the transponder terminals.

Or even, check the battery voltage with the car running. Could have a weak battery that is sucking down enough that the voltage drops low to the transponder.

Frog's comment about the 'cone' shot and through that small hole is true also. The 1" hole reduces the amount of detection time the loop has, Sorta like artificially narrowing teh beam of a flash light.

[mblanc]

your problem is that your transponder is too close to the track. It broadcasts a cone shape signal. The higher the transponder the larger the pattern it broadcasts onto the track surface. Raise it to 4 or 5 inches and you will probably double the size of the pattern hitting the surface.

Agreed.

Been there and done lots of different 'perfectly correct' installations, that were very low, and still had the same problem, and was always talking to the T&S people, who were getting annoyed with having to hand score me, from low and missed hits. I walked by a Swift that just had it zip tied to the front hoop, and asked how the heck that could work?, driver said they had no idea, put it there years ago, and never had any problems.

I raised it about 8", in a non ideal location, lots of stuff in the way, and no more issues.

[Roux]

I also had a weak signal and made my aluminum opening about 1/2 inch wider and all is now well. the hole is in the underside of the body panel so the distance up from the track is 12 inches. hard to explain the layout but the shadowing that had not been an issue for many years now showed up as a problem. Issue came up at Pocono. Not sure if they repaved over the pickup wire and weakened that part of the system. Odd that it started acting up after so many reliable years

Steve

[formulasuper]

Since the hard wired model uses less than 40 mA of current it wouldn't take a very good connection to supply the required power for operation. My guess is the hole size & height is the problem, as stated previously by others.

[Charles Warner]

Odd that it started acting up after so many reliable years

Gee, odd that the recurring theme in the discussion is age of the transponder?

[rickb99]

Charles, I think there's a hint above that it isn't in the same car any more

Since the hard wired model uses less than 40 mA of current it wouldn't take a very good connection to supply the required power for operation. My guess is the hole size & height is the problem, as stated previously by others.

Formula,

If you want to be electrocuted, it's the current.

But with solid state electronics, it's all about the operating voltage. If your device is designed to functions between 11.8 and 13.4 volts, it doesn't care if you have a source that will deliver 1,000 amps. If the voltage is below 11.8, it won't work.

[Charles Warner]

Charles, I think there's a hint above that it isn't in the same car any more

Rick,

The recurring theme seems to be that as the transponders age the signals get weaker, requiring us to somehow alter the signal pattern/propagation in order for the track sensor to pick up the signal. According to the T&S people at RA this is an all-to-common occurence which is usually solved by simply opening up the hole through which the signal travels. That is exactly what happened to me. 4 years of perfect operation through a 2" hole approximately 3 inches off the track surface. Then, it started to give sporadic hits - not enough to be reliable. After talking to them I did as they suggested - opened the hole up to about 4". No other mods, and it worked as before.

Again, they suggested contacting AMB. It could be something as simple as cleaning off the transmitting section of the transpoder. But, at the end of the day, these problems seem to occur after 4 years or so of perfect operation. All coincidence?

[formulasuper]

Their warranty runs out after 3 years.

[rickb99]

Rick,

But, at the end of the day, these problems seem to occur after 4 years or so of perfect operation. All coincidence?

No, it's probably not a coincidence at all.

I was just ref. Russ's 2nd post where he mentioned ... "the first car that used it....". So he did put it in a different car.

As to why the signal seems to deteriorate shooting through a hole after about 4 or 5 years, could be many things. Unless you have the 'inside track' to AMB it's really difficult to find much info on exaclty how the encoding is done, what frequency they operate at, output signal strength, beam width, type of radiating element, etc.

GOOD idea to try cleaning the output end of the transponder once in a while. As our cars a capable of collecting and unreal amount of crud inside the chassis every weekend, I suspect the transponder window is the last thing people think about wiping off.

I've never seen the circuits inside a transponder. So, what's happening internally that could cause this, I have no idea. I'll ask our T&S people to keep an eye out for a trashed one and I'll open it up.

Their warranty runs out after 3 years.

LOL, there's your answer as to why they go bad in 4 or 5 years. I'm shocked this doesn't happen at 38 months

[Charles Warner]

there's your answer as to why they go bad in 4 or 5 years. I'm shocked this doesn't happen at 38 months

Ergo, caveat emptor when buying a used unit. I presume one could get the number and contact AMB to determine the age.

[RussMcB]

This has been a good thread. I appreciate the suggestions.

My current transponder was in two previous cars before this one, and the mounts were different, so there is a very good chance that my current mount with 1" hole is not good. I hadn't really thought about the "cone" shape aspect. I figured a straight shot to the track was all that was needed. It makes sense that a wider signal will help.

[formulasuper]

After reading all these post where people feel there is an advantage to mount them inside the car, peeking out thru a hole, I'm wondering if mine being mounted outside in the airstream is what is allowing some of the FA's to beat me down the straights!

[rickb99]

LOL Formula, you've figured it out

On the other hand, we have ours mounted directly behind the right hand, symetrical shaped, flat A-arm.

Now, if you've been following the other thread about whether these A-arms are airfoils or not, you'll understand why I think this is the ideal mounting point. With the transponder angled forward at the bottom by 0.037 degrees, it's giving us some addtional downforce which is very helpfull in right hand corners at Pacific Raceway.

[formulasuper]

LOL Formula, you've figured it out

On the other hand, we have ours mounted directly behind the right hand, symetrical shaped, flat A-arm.

Now, if you've been following the other thread about whether these A-arms are airfoils or not, you'll understand why I think this is the ideal mounting point. With the transponder angled forward at the bottom by 0.037 degrees, it's giving us some addtional downforce which is very helpfull in right hand corners at Pacific Raceway.

Hey, I thought I was the only one using my transponder for downforce! I've got it mounted slightly aft & below my front/RH upper rocker arm, which after several hours of adjustments in the local Lockheed Aerospace wind tunnel has shown a significant inprovement in downforce.

[problemchild]

I have learned .... the transponder works worst when mounted in the safest location and has the strongest signal when mounted in the most vulnerable location!

[datadude]

[FONT=Arial-BoldMT][SIZE=4]

INSTALL A TRANSPONDER ON A CAR

[/SIZE][/FONT][FONT=ArialMT][SIZE=2]

The mounting position of the transponder of a rechargeable or Direct Powered transponder is the same. The
position must be identical on all cars competing in the race. Fix the transponder vertically, at a maximum of
60 cm (2 ft) above the track. Make sure that the transponder has a clear view to the track with no metal or

carbon fiber underneath. Maximum operating temperature should not exceed 122F/50°C.

This was taken from AMB site

Make sure the hole you cut is at least 6 inches.


[/SIZE][/FONT]

[dave parker]

The last 2-3 events I've been told that my transponder signal is weak. I've checked the mount and it seems fine. It is mounted in my aluminum nose box and pointing through a 1" hole about 2" above the road surface. It is hard wired. I suppose something may be causing it to get less that 12-13 volts.

It's about 5 years old. They're pretty expensive, so I don't want to buy a new one.

Any thoughts or suggestions?

Maybe I can ask the T&S folks if they have a way to test them ...

TIA.

Russ
I too had this problem with my original transponder (it was four years old). I called AMB and described the problem (weak signal, per T&S not no signal). They asked that I send them the transponder so that they could test it. About three weeks later I received a NEW transponder via UPS. Included was a letter stating that they tested my old unit and found some "problems" in the internal circuitry.

Give that a try.

cheers
Dave Parker