V2 TRANSPONDERS TESTED AND VERIFIED

Thank you everybody for your patience. From now on, the v2 transponder is the primary version you see when visiting openstint-transponder. The previous version is available in a separate branch (v1).

Highlights:

• similar signal level to an RC4Hybrid
• works down to 2.8 V supply rail
• flat signal level down to 3.4 V (miniZ and 1S-battery is support)
• much easier to tune, less harmonics, symmetric sidelobes

The new design was tested with ATtiny 816/1616 and 3217. I'm certain it runs on 3216 and 416 as well.

MEASUREMENTS

Signal strength (blue: RC4H; yellow: OpenStint v2; same distance)

Bit transitions:

Occupied bandwith:


TRANSPONDER PANELS FOR SALE

I have now multiple panels which I'm offering for sale. Each panels are programmed and tested with the latest OpenStint firmware. 30 EUR/panel (8 pcs transponders). I'll send them as a regular, sub 50-g mail. Shipping costs are about 5 EUR when sending untracked, and 10-12 EUR when sending tracked. Contact me in PM for details.

Note: this deal works only if you need 1-2 panels; for larger quantities, go to JLCPCB.

WHAT'S NEXT?

The transmit antenna is on L2-L3, leaving the bottom layer free for a 3rd loop. I think this transponder can be smaller when the bottom layer is utilised as well. This time I'd like to get rid of the 10 panels I have before spinning a new version though.

PS. savage24x: you're good with the HF balun, the preamp is a nice-to-have. I have a single piece left from earlier prototypes, contact me in private.