User Tools

Site Tools


How to connect external GPS module to Yaesu FTM-300

List of parts


  • 2.5mm TRR jack cable or adapter from 3.5 mm TRR cable
  • USB cable to power the system
  • MAX3232 chip

  • GPS module Beitian BN-220

  • Heat Shrink

Development and testing

  • Strip board
  • Header pins
  • MAX3232 chip
  • Dupont connectors
  • Heat shrink
  • USB cable or some other way to power the system
  • RS232 to UBS adapter

  • u-blox u-center v22.02 - download link
  • Yaesu FTM-300 external GPS connector pinout

Development board

Pictures of the development board used to setup GPS module



Yaesu FTM-300 requires higher logic levels than BN-220 can provide. MAX3232 is used to translate lower TTL logic levels to higher RS232 logic levels - Quick tutorial here. GPS module will require to be set to GPS constellation only in u-center. Radio needs to be set to external GPS device. Transmit from the radio Data Tx to GPS receive Data Rx does not need to be connected. Baud rate is set to 9600.

ei5iybpastebin3.txt · Last modified: 2022/04/12 21:56 by ei5iyb