Available charts
GPS Comparison Chart
Feature Blue Logger Earthmate LT-40 Earthmate BT-20 Earthmate PN-20

Power Battery- life 8 hours
Car and wall adaptors included
USB power- no batteries needed USB powered or Li-On battery Li-On battery or 4 AA batteries

Connection to computer Bluetooth Only USB Cable USB or Bluetooth USB Cable

Memory on device Yes- logging for 50,000 points No No Internal- 75MB, room for 2 GB SD card

NMEA 2.0-compliant 12-channel receiver Yes NMEA compliant 16-channel Yes Yes

Chip set SiRF starIIe/LP low-power GPS STMicroelectronics new high- sensitivity Teseo chipset featuring DeLorme ConstantLock technologies Low-power baseband and RF chip set (RF chip based on the ultra-low-power silicon-germanium BiCMOS process) STMicroelectronics chip technology with SiGE front-end and DeLorme firmware

Raw data logging (ephemeris) Yes No No No

LED indicator Yes Yes Yes Color Screen