some ID-12LA range distance is too short (almost 0cm)

[henrylaredo]

Dear Sparkfun, we have a problem with some units of ID-12LA, we purchased a lot of 15 units and 4 units of them has a range distance of almost 0cm, the other ones from that lot are working perfectly. It’s a lot that we purchased the last year and we use them according to the demand of our costumers, and yesterday we use one of them and when doing the testing we notice that strange behaviour, please check the attached video that we made yesterday, where you can check the problem we are talking about.

https://www.youtube.com/watch?v=_0XPphT … e=youtu.be

Thanks for your attention.

[TS-Chris]

Hi Henry, and thanks for your post!

I see a ground plane on the board you have that’s not working correctly and no ground plane on the other.

What happens with the ground plane is it acts as a shorted turn and de-tunes the antenna inside the ID-12LA causing it to have poor range. Page 15 on the [data sheet has more information on this if you need more information.

I’d recommend removing the ground plane from the top and bottom layers of your PCB and that should fix this issue.

](https://cdn.sparkfun.com/datasheets/Sensors/ID/ID-2LA,%20ID-12LA,%20ID-20LA2013-4-10.pdf)