# AMB20 - Lap Counter System



## connywesth (Nov 27, 2010)

I have replaced an old AMB20 Loop antenna with my own antenna cable (ordinary thin electrical cable) and a resistor and 2 banana conectors, works perfectly fine.

Now I have the need of replacing the Loop box, by soldering my home made solution, but I dont know what cercuits to use and how to connect them.

I have found some schema for a 7 Mhz radio-system but this probably dont work in this case, but i suppose it basically uses the same principles.

I have searched the internet for several months but have not found any schema for this, any one that has?

The AMB20 transponders use induction to send information through the loop, that i know.

I have tried one solution that did not work, because the entire coaax became receptive as an antenna. I suppose the loop box "stops" the receptiveness of the transponders so only the actual loop-antenna will receive the transponder signals.

I do this the hard way because i like to learn how it works and the budget is almost zero, so buing an extra loop-box is not an option.


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## Stateline R/C (Apr 2, 2005)

you need double shielded co ax it works i have lots of loops made


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