Proxmark3 community

app_o1

Contributor

Registered: 2013-06-22

Posts: 247

Reading Range

I am building a small LF reader (similar in size as a ProxPoint).
When the antenna sits right above the circuit board, I am loosing a lot of reading range.
There is a thin layer of epoxy between the antenna and the pcb but it does not seem to help...

What can I put between the antenna and the pcb to avoid interference and lost of reading range?

I don't have much space, 2 mm.

Thanks

0xFFFF

Administrator

From: Vic - Australia

Registered: 2011-05-31

Posts: 632

Re: Reading Range

If you can help it, you should design your PCB in such a way that the components and tracks are not underneath the coil. This will help with tuning and range. Condensing and / or using both sides of the PCB should be considered.

Is this a PCB antenna, enamel copper wire or something else?
What sort of read range do you have at the moment?

app_o1

Contributor

Registered: 2013-06-22

Posts: 247

Re: Reading Range

If you can help it, you should design your PCB in such a way that the components and tracks are not underneath the coil. This will help with tuning and range. Condensing and / or using both sides of the PCB should be considered.

Is this a PCB antenna, enamel copper wire or something else?
What sort of read range do you have at the moment?

It is a 125 kHz antenna. Enamel copper wire with about 150 turns. It is factory made. With the capacitance and inductance matching the frequency.

When the antenna sits on the side (away from the PCB), I am getting 7.0 cm for a ProxCard, 3.5 cm for a ProxKey III and 3.0 cm for a ProxKey II.
With the antenna sitting on top of the epoxy, I get 3.0 cm for a ProxCard, 0.20 cm for a ProxKey III and nothing for an old ProxKey II.
With the antenna slightly "stuck" into the epoxy, I get 1.0 cm for a ProxCard and nothing for the HIDII&HIDIII.

I need to run more test. I don't think the epoxy is at fault here.