Dang it! I ran out of space and I’m still not close to 125kHz
[=] ---------- LF Antenna ----------
[+] LF antenna: 13.35 V - 125.00 kHz
[+] LF antenna: 15.14 V - 134.83 kHz
[+] LF optimal: 40.67 V - 171.43 kHz
[+] LF antenna is OK
I have enough ferrite and wire to try another day.