Test:

Today a succesful testday at our local racetrack. We used two 4wd FG Mini's, the Cano-tranponders with the round shaped PCBA's, a decoder with miodified processor to have USB link to the laptop and to supply the decoderbox over USB. The loop is build inside two heavy rubber sheets for easy transport to other tracks.

Remaing picture of testday at local track:

Many thanks for posting the photos! Your progress is very gratifying to me.

The loop inside the rubber sheets is a great idea.

Thank you Howard for your kind reply! Here some more details for the loop and the build.
It started in our kitchen on the floor because of cold temperatures during the winter period. The rubber sheets are taken from our office were we got new furniture and the anti-static mats were replaced by new onces. I took all old mats home...
I realize these mats have some kind of conductive layer, but if you think of put the loop on tarmac or (wet) sand, this also conducts. The conductance is not low-Ohmic so it should be OK. As an example I also attached a picture of how these mats look like.
I needed a wider loop as what I can build from one sheet, so I needed at least 2 next to each other. The top-layer is then attached in a way they overlap the bottom sheets. If one can get hold of rubber-sheets in the correct width, this is easier.
The wire of the loop is first stitched by thin double_sided tape and after that on both sides of the wire double_sided foam tape is applied. This secures the wire even better once the top sheet is placed. After all 3 parts of the top sheets are in place, I used stapples all around the mat to prevent the double_sided foam tape from detaching while rolling the mat during transport. Every 1cm has a stapple :-). Enjoy watch the attached pictures:

The rubber mats are stiched in such a way the result is a shallow step in the direction the cars appraoch and leave the loop. The bottom sheet is about 10cm wider at both ends so the front spoiler will not 'hook' the rubber. Here the remaing pictures:

+1 And not to mention offering a pretty good short course on high frequency electronics, RF electronics, DSP, test and debug... and many more. Lots of gems to be found in this thread!

Hi,

First some background bits : I'm together with friends runing an RC club (mainly 1/5 TT) in France (not far away from LuLuFRA). On our track, we do have an AMB type loop burried in the ground. We use it with an AMB system we borrow to other clubs when we do a race/competition on the track. As a digital electronics & SW engineer, I was looking at a cheap way to reuse that loop and do a timing system at cheaper cost than the existing MyLaps solutions...

When I did found this forum, I was amazed by the huge amount of work you guys (and especially Howard) did ! you almost made my day by providing an almost done solution... Thumbs-up to all of you.

I intend to 1/ adapt the amplifier, 2/ reuse the phase amplifier/DPD/SSC, 3/ use an STM32F4 (working there ) and 4/ create a custom app...

I have analysed every single of your schematics, and going through the logic ones (DPD, SSC, PDS), I realized this is a very nifty piece of logic work

When it comes to the analog part of the design I have much more struggle especially understanding the behavior of the loop amplifier (as I said I'm more of a digital guy). What I understand, is that it is based on a pretty standard differential amp setup and the loop is connected toward the diff inputs.

I have 2 questions (at least to start ) :
- I don't really understand what is the role of the Q5/R4/R5 part of the design.
- What do you consider as an input impedance for the diff amplifier - I need to adapt this to my AMB loop (T2FD type with 472Ohm). If I would understand the input impedance of the amp, I would be able to do the tuning (I have a good hamradio friend that can help there) ? I have done some googling and tech search but fails miserably

Keep it the very good work, and I also hope to hear back from Payalneg on the viterbi and convolutional settings he found ( may be the standard NASA backed one...). Most of my mates are having RC4 hybrid or Pure RC4

Rgds,
PyB

Welcome to the thread!

Q5 provides temperature compensation for the bias voltage for the input differential pair, Q1 and Q2. R4 and R5 feed the bias voltage to the pair, and (along with the input resistance of the transistors) establish the amplifier's input resistance.

Each transistor in the input pair runs at about 2.5mA. Assuming a beta of 100, that gives an effective small-signal input resistance of about 1K ohms each. In parallel with 2K, the result is about 660 ohms. Since there are two inputs, the timing loop sees about 1300 ohms. (At 5MHz, it's mostly resistive.) This can be padded down with the components at J3, J4, and J5 to match the loop size. The components also change the loop tuning.

The loop amplifier uses the timing loop as an inductive coil (not as an antenna) to receive the magnetic field from the transponder. The components set the loop's resonant frequency to 5MHz, with a low Q (wide bandwidth) to follow the transponder's relatively fast phase-shift modulation.

Hi guys. Sorry for delay. Busy at work.
Yes, Payalneg did good job - transponders read as is, with original amb numbers.
I don't have any details about how he did that, so you can try write to him - maybe he will answer.

I sended a message about coding to Howard.

Ok, howardcano, can we get some details about the coding?

Thanks

Payalneg has sent me some information, but he asked that I keep it confidential, which I will do. It will be his decision if he wants to share it.

Hi felows, nice work do you have, learn lots reading your posts.
Has someone test the Cano sistem in boats?
Any chance to adapt for boats, i have a race boat clube and like to build and test a system like yours.
Regards and keep good work.

I haven't tested it for boats. You may run into problems with reception due to the conductivity of the water.