(*****) NFC antenna amplifier/Resonance Circuit V1 & V2.1

[Pilgrimsmaster]

NFC antenna amplifier/Resonance Circuit project

Made by @Hamspiced

This is merely my review; full details on the actual project can be found here

NFC antenna amplifier/Resonance Circuit project

Satur9 is going to crucify me. I have hated the fact that my phone case on the pixel 7 impacts NFC functions so much so I got really interested in reading the projects that Satur9 posted. I don’t have a VNA scanner yet, although it’s on its way. But I am impatient. So reading back on the forums here I saw someone that just grabbed an NFC fob, ripped the old chip out and added a capacitor. So I did approximately zero math, I didn’t measure resistance inductance or capacitance. I had a ton o…

INTRODUCTION

WHAT IS THIS?
Tuned circular 13.56MHz HF Antenna to a LC Tank Circuit

WHAT DOES THAT MEAN?
Add this to your reader, and you should see increased read ranges

WHAT DOES IT NOT DO?
Low Frequency 125kHz

TESTING INCLUDING READ RANGES
Some interesting results
For this I used my Phone ( Samsung S21+ ) PM3 Easy, PM3 RDV4 and a Flipper Zero

I considered testing with a PM3 Easy and RDV4, but decided I would focus on more portable readers for now.
I may do PM3s later
Gah, Whatever, I did these too…

PHONE

Phone Without
xSeries ( xMagic ) Contact
Flex ( FlexM1 ) 5mm
Card ( Mifare Classic ) 20mm

Phone With
xSeries ( xMagic ) 5mm
Flex ( FlexM1 ) 10-15mm
Card ( Mifare Classic ) 30

FLIPPER

Flipper Without
xSeries ( xMagic ) 5mm
Flex ( FlexM1 ) 15mm
Card ( Mifare Classic ) 30mm

Flipper With
xSeries ( xMagic ) 15mm
Flex ( FlexM1 ) 25mm
Card ( Mifare Classic ) 15mm (interestingly degraded range)

PROXMARK3 EASY & RDV4

Proxmark3 Without
xSeries ( xMagic ) Contact
Flex ( FlexM1 ) 10mm
Card ( Mifare Classic ) 60mm

Proxmark3 With
xSeries ( xMagic ) 10mm
Flex ( FlexM1 ) 15mm
Card ( Mifare Classic ) 60mm (antenna amp on implant) killed signal (antenna amp on PM3 antenna)

TEARDOWN

PROs
• Huge improvement on Phone readers

• Good improvement on Flipper zero

• OK improvement on Proxmarks, but mixed results

• Is thin enough to sit inside phone / flipper covers

• These can be used in conjunction with qi wireless charging

• Did I mention how good it is with your phone, Really Good!!!

CONs

•

• Fragile!?!

• If you get the free option from @hamspiced, you’ll need some antennas, caps, VNA and solder kit

• They are crazy thin which does make the flex pcbs a pain to solder to.

“HACKS”
Possible encapsulation with tape

PRICE
USD$FREE Bare board ( No Cap, No Antenna ) Dangerous Thing community offer only
USD$8.50 Same as above, But on Tindie and not free
USD$50 Tuned working product, bought on Tindie

SUMMARY:

LINKS AND RESOURCES

RFID Antenna Adapter for Tuning Antennas by Midwest Gadgets LLC on Tindie

PCB’s come bare, you will need to supply your own Antenna coil and capacitor

13.56MHz NFC Amplifier V0.1 by Midwest Gadgets LLC on Tindie

POLL

Rating by the community

PLEASE ONLY VOTE IF YOU HAVE ONE OR HAVE USED ONE

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PRODUCT NAME 1-5

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[Satur9]

Good job @Hamspiced . You served most people’s purpose for the resonant repeater stickers with this. I appreciate it.

[Hamspiced]

I still need to finish making v2. I tried on my own but failed bad and had to throw away the entire lot.

Should have more time open up shortly so I can get back in it

[Pilgrimsmaster]

@Hamspiced

I tried on my own but failed bad and had to throw away the entire lot.

Where was the error? The production or Spiced Ham?

@Satur9 is frequently offering his knowledge, and this falls in his wheelhouse, If you have a question, he’s the guy to ask

[Hamspiced]

I reached out, got overwhelmed with work and didn’t follow-up. Failure in my end.

I messed up my circuit in kicad entirely and couldn’t find a proper capacitance given the circuit I made. I think it has to do with the thickness of the traces.

I was going to try to get a working version first then reach out to see the idea he had about doing this without onboard capacitors.

But I made two versions, one for 13.56 and one at 125k for another project I’m working on for Amal. Both runs were trash. Do I’m waiting until I can get some actual dedicated time to look it over and adjust.

PPD is a hard y’all. I hope your wives never have to go through it.

[Satur9]

@Hamspiced

I’m waiting until I can get some actual dedicated time to look it over and adjust.

Well I’m around if you want help figuring anything out, and I can even throw in some money for PCB orders if you need.

@Hamspiced

PPD is a hard y’all. I hope your wives never have to go through it.

I’m really sorry to hear that. I hope everything went okay with the birth and it’s just the natural course of the emotional rollercoaster she must be going through. Things are tough anyway right now so she’s justified in any anguish experienced while we’re all already at an emotional high water mark.

[Hamspiced]

sorry for the delay to reply to you.

I think i got it figured out. If this run is successful i may reach out in reducing the footprint. I still havent jumped into altium and i think that is my next move as kicad is a bit too basic.

PPD is just a hell of a disease. i feel pretty safe in calling it that. My baby boy is super healthy. My wife though is just a different person now. its hard. birth is hard on her, breast feeding is hard, marriage is hard…

[Satur9]

@Hamspiced

I still havent jumped into altium

I just finished my third design from scratch in Altium and I really love it honestly. Very sensible piece of software, and there’s a ton of features you can utilize or not to make your life easier

[Hamspiced]

Maybe i am just getting old. Its hard for me to take time to dedicate to learning a whole new software. Ill get in there i just dont know the timeframe.

[Pilgrimsmaster]

2 voters currently

Average vote 4.5 Stars

I voted 5 stars

Somebody else obviously voted 4 stars.

I’m not calling anybody out, but I am curious as to the loss of a star

[Pilgrimsmaster]

@Hamspiced
If you have time would you be able to do the same test as I did with your V1 inside a Flipper case?
I was just surprised with some of the results.
It was probably my placement of the antenna amp.

MY RESULTS

@Pilgrimsmaster

FLIPPER

Flipper Without
xSeries ( xMagic ) 5mm
Flex ( FlexM1 ) 15mm
Card ( Mifare Classic ) 30mm

Flipper With
xSeries ( xMagic ) 15mm
Flex ( FlexM1 ) 25mm
Card ( Mifare Classic ) 15mm (interestingly degraded range)

Also, now that you have the V2’s available, and if you have time Would you be able to do a range comparison between them also?

[Hamspiced]

For visibility, I would like to but I’d rather the tests be objective so I’m reaching out to you via DM to send you one to continue your review.

[Pilgrimsmaster]

@Hamspiced

to send you one to continue your review.

The courier pigeon hs been dispatched

It may stopover in LA then Hawaii before landing on my golden shores.

Review will follow shortly after…

Thanks Spicy Ham

[Hamspiced]

You’re welcome. Don’t get the hopes too high. V2 isn’t as tuned as V1

[Pilgrimsmaster]

@Hamspiced

Don’t get the hopes too high

The V1 is AWESOME, even if the V2 is simply good, it’s still an improvement on stock antennas.

I’ve just been using my V1 with my ApexFlex 2FA, and man, it is so good to just know that you don’t have to play around with positioning; close enough is good enough, it speeds the whole process up.
Every time I use it, I appreciate it, thanks again

[caj380]

This is awesome!!! I just ordered a bare flex board and a complete unit on Tindie. Happy to support you @Hamspiced !

[Hamspiced]

I appreciate it man. Did you happen to use the DT Promo code i have listed in my profile? Someone said they had issues with it and i had to adjust the number of uses so it should work. Im sending two out to you as i hate charging members of the forum for these.

For anyone else reading this. Both the Adapters and any completed V1 units i have made stock of are free to members just message me!

[caj380]

No, sorry. I didn’t realize they were free for DT members. It’s all good though. I don’t mind paying. That way you can afford to do more projects

[Hamspiced]

my tindie store has helped towards funding costs of this project. I sell quite a few flipper boards and adapters so with the production costs of these prototype runs it is significant.

[LordSethos2000]

Yep the code didn’t work for me either.