This link is only available for Mini Duplex MMDVM boards. Setting up Pi-star software and raspberry hardware (rpi 0-3) New pi4b requires removal of Right Socket. Features: Pi-star general configuration for MMDVM_DUPLEX Set Controller Mode: Duplex Repeaters or Simple Radio Frequency: Freq: 144-148, 219-225, (primary band) 420-475, 842-950 Duplex Mode: Example: RX:438.000000 TX:433.000000 Duplex Mode: Example: RX:145.000000 TX:433.000000 Simplex Mode: Example: RX:438.000000 TX:438.000000 Radio/Modem Type: STM32-DVM/MMDVM_HS-Raspberry pi Hat (GPIO) or any other (GPIO board) Options: (not required now, some older boards need to be set) Admin->Expert->Edit MMDVMHOST->RXOFFSET=0 TXOFFSET=0 (default value in pistar) (Update: 2019/2 New 3225 TCXO so offset is 0 ) Update new firmware: (pi-star / Expert / ssh access / user :pi-star pass:raspberry) sudo pistar-mmdvmhshatflash hs_dual_hat The default BER is less than 5% and the default offset is 0. If the BER is greater than 5%, it can be corrected by offset as long as the signal can be received. Specifications: Name: Hotspot Board Material: printed circuit board Package size: 80 * 50 * 20mm / 3.15 * 1.97 * 0.79in Package weight: 10g / 0.35ounce Packing List: 1 * Hotspot Board