Proxmark3 community

HAMsandwich

Contributor

Registered: 2018-11-01

Posts: 8

[SOLVED] [RDV4] Antenna connection

Wanting to design a LF antenna for the RDV4 platform (since that's what I bought) but I'm not sure what's up with the three terminal antenna connection. Did a quick test with a multimeter and only the PWR and RAW ports have continuity on the antenna.

Last edited by HAMsandwich (2018-11-02 08:34:30)

AntiCat

Contributor

Registered: 2010-01-01

Posts: 22

Re: [SOLVED] [RDV4] Antenna connection

In contrast to previous designs, the capacitor of the RLC circuit is not on the Proxmark3 Rdv 4.0. Now, it is part of the antenna (pcb).

To be able to add a capacitor the Proxmark3 Rdv 4.0 features the GND terminal.

The simplest antenna possible is a coiled wire connected to PWR and RAW and a capacitor between RAW and GND.

Last edited by AntiCat (2018-11-01 22:07:08)

HAMsandwich

Contributor

Registered: 2018-11-01

Posts: 8

Re: [SOLVED] [RDV4] Antenna connection

Figured it out, thanks to AntiCat, and got something thrown together for coupling to small implantables. ~150pF of bulk capacitance with 10-50pF of trim capacitance and I estimate a 10mH ferrite inductor I had laying around. Now to figure out my protocol issues...

Measuring antenna characteristics, please wait.........
# LF antenna: 66.41 V @   125.00 kHz
# LF antenna: 40.42 V @   134.00 kHz
# LF optimal: 66.41 V @   125.00 kHz
# HF antenna:  0.00 V @    13.56 MHz
# Your HF antenna is unusable.
Displaying LF tuning graph. Divisor 89 is 134khz, 95 is 125khz.

Last edited by HAMsandwich (2018-11-02 08:24:12)

iceman

Administrator

Registered: 2013-04-25

Posts: 9,537

Website

Re: [SOLVED] [RDV4] Antenna connection

Cool!

iceman

Administrator

Registered: 2013-04-25

Posts: 9,537

Website

Re: [SOLVED] [RDV4] Antenna connection

I suggest you pull latest/compile/flash from RRG repo.  The LF support has become much better.