Is it my transponder or the track??
 

Like most of you, I have a couple of transponders. For the past few weeks I have been racing off road and the track officials have stated that I had a DNS or a DNF. Clearly, I was on the track and putting down laps. I checked the transponder and saw that the light was on and all the electronics were running properly. I even changed the reciever battery.
My transponder is 3 years old. Never been hit or impacted. Sometimes it reads and sometimes it doesent. Is it the transponder or the track?:confused:

I need to know the answers to the following.
1. Do transponders use a frequencey close to the DSM channels?
2. Mounting a transponder verticaly make diffence in reading it?
3. How deep can the cable be in order for it to be effective?
4. Does it matter how much energy the battery is providing to give a signal?

Check the LED on the transponder when you move the servos with your radio. If the LED blinks or dims a bit, you are losing power to the transponder.

I had an issue with this when racing electric and I added a capacitor to a spare input on the receiver. However, with nitro racing, that's not really applicable. So if the transponder LED does blink, then perhaps it's time for a new receiver pack.

1-No
2-Must be mounted in the horizontal position.
3-No more than 3/4 inch in asphalt or concrete.
4-Very little. If you’re using the 3rd channel of the receiver you should be fine. If you use a "Y" adapter in a 2-channel receiver then use the one with the lowest current draw servo (usually the throttle).

check all your wires and also, where do you have the transponder mounted. If you have it mounted to a servo with a metal case, it could have an impact on how the signal is being "blocked?" Your race director should have noted this to you during warm up, and offered a rental/track transponder to help you diagnose your problem. I've had transponders that were 7 years old and the only reason I got rid of it was becuase the case got ripped off, but it still worked. They are encased in epoxy, so I don't think that the trasnponder could be at fault, unless the wires have a break.

I didn't read before that you race offroad. This is from the AMB manual:

"In case of an OFF-ROAD track cover the loop with carpet or similar. The carpet can be covered with sand."

The loop is a big issue with offroad tracks. If it's deeper than a couple of inchs or if it's in a fast section of the track (or both) it can be a problem.

I prefer the "Bridge" loop with offroad.

GETTO,

These guys hit on everything. The two loops at CB are down about 3" and 4" down. Have you had problems there?? An easy check at the track would be to ask what there background noise is. This should be no higher then 40 points. Also see if they leave the system in transponder test during practice. Your signal strenght should be 60 points above background noise.

Give you an example, We were have problems at the OC. Background noise was 87 (way to high), transponders were hitting around 120. Difference 33 points. Hardly anybody was hitting and I was hand counting.:( Replaced the COAX. Now the BN is 22, and cars are hitting around 120, no problems at all.

Thanks guys for answering so quickly.

Ed, I have had no problems with CB. I'm running at BDiamond with my Jammin. It was the same transponder that I ran at CB. BD's loop is located at the far end of the 190 foot straight. You have to teach/show me how to read BN points value for these transponders.

Bob, The track was raised more than a foot. I suspect the loop is buried deeper than 6 inches. My issue with that hypothesis is that 90% of the other racers are reading. This past Saturday, there were seven guys that had simular problems that I was having. Because of this issue, I called AMB and sent my transponder back to have it checked.

RC, I was so ticked off that I replaced my reciever battery. I checked for it's capasity and it was real good. a 1400mhz I was getting 1320. The light was on and was lit very strong. I moved my transponder to the veritcal because I thought the Jammin's chassis was too thick and the signal was not penetrating. I was wrong after realizing that I am putting the hand out higher and through my truggy's body:weird:. That was reading.

I was ticked off becasue the transponder issues put me into the "B" main. Two quailfiers were listed as DNS when I was clearly on the track. I went on the track with a vengence and lapped the track to get to the bump up spot. In the process, I smoked a motor in the last 30 seconds of the "B" main. I had a 19 second lead on the second place runner at that time.

near servos, on carbon fiber also can cause this, a dead cell in your pack can also cause this, but if you changed packs and still had the issue. to trouble shoot the problem deeper take another transponder and see if you get the same results use a friends in practice to see if he gets the same results or not. very often in off road it is loop placement the loop tends to sink beyond the point of a good read and not all transponders are effected immediately but soon if it is sinking there will be more with your same issue.

Did anyone else have the same problem at the race? If not send your transponder in for service. :)

good question, and an even better solution. had mine for 6 years or so sent it in once and it is still on point at all tracks that I attend races at.

There were a few guys that were not scoring as they put down laps.. My truggy was not scoring at all with my personal. There was something strange that did happen. I grabbed a hand out transponder and had my PT still plugged in. When I was in the middle of the qualifier, the organizer said that I did not start! I was in the middle of a serious fight and was not getting scored by either the hand out transponder or my personal. I had to do something on my behalf. These things are just too expensive to set aside.

I have had this problem more than once, both times it was due to loosing a cell in the reciever pack. Have even put used loner packs in at the the track with the same issue. Purchase a brand new pack, charge her up and things should be better. These little transponder are pretty diligent so I do doubt it has fault, vulnerability lies with frayed wire leads and bad connecters.:tire:
Just my own experience.

Here is some pictures for you Ghetto.

I would have looked for this first. And if the noise was low, and your signal strength was low, I would have tried moving it around to an unobstructed position. Or tried just the PT and a receiver pack, before I sent it in.


First pic was with the bad cable. Tp's worked about 10% of the time.

Second pic is with the new cable. No problems at all.

Thanks again Ed!
That screen does not look like the one that they have at BD. I have to ask the guys at Hoobytown what program they used.

I did move the transponder around the chassis. I would up velcroing the unit to the side of the battery box. That was the clearest and lowest point on the chassis. It was mounted verticaly. That worked for two weeks of racing.
The third week it read half the time. Last weekend it did not read at all. That was when I replaced the battery from 1400 to a 1600. It still did not read.
The Jammin Crt has the trasponder mounted in front of the throttle/break servo. That is right above a carbon fiber servo mount and a 3mm chassis. Other Jammin drivers don't have a problem with their PT mounted there. I installed the hand out on the body right above all the electronics, carbon fiber and chassis; it read..
I'm just confused why the hand out and personal both didn't read during a qual ? Too many mysterious happenings.

I don't think that BD has J-lap. It does not call out laptimes. I hear the orginizer giving the stats. I do believe that their scroing loop may be too deep. Wonder if I can install a DieHard 850 CCA battery in a trailer on my truggy? It probibly would not read either...

This is from the AMBrc manual:


1- The transponder must be mounted horizontally (flat). The position of the transponder must be identical in all RC model cars competing in the race for best finish accuracy.

2- Transponders must be positioned no higher than 15 cm / 6” (lower is better), with no metal or carbon fiber between the transponder and detection loop.

3- Fix the transponder to the car with help of double-sided adhesive tape or nuts and bolts (in case of gas cars). Make sure the transponder can not get detached during a race.

4- Connect the power plug to a free servo channel or use an Y-splitter.

5- Check for green led on the transponder when radio receiver is on.


Carbon Fibre or metal chassis:


If the AMBrc transponder is fitted directly onto a carbon fibre or metal chassis, the signal from the transponder is weakened severely, which shows as low hits and strength readings from the AMBrc decoder (in AMBrc mode only). Try to find a position for the transponder free from the chassis, for instance on the front bumper and check for better readings from the decoder.
Hits should be no less than 10 (at speed) and strength not lower than 100 points, see also: Operating the system / Trouble shooting.

If no good horizontal position can be found, as last resort, the transponder may be placed vertically, with the wiring facing the left- or right side of the car. In that case the signal from the transponder exits over the front and back of the car.