GPS Receiver - EM-408 SiRF III (20 Channel)

Replacement: None. We are no longer carrying this EM-408 GPS Receiver in our catalog. This page is for reference only.

The EM-408 GPS receiver from USGlobalSat based on the spectacular SiRF StarIII chipset. This complete module is built upon the same technology as the ET-301, but includes a built-in patch antenna and an MMCX connector for an optional external antenna! 5-pin interface cable included.

Please note the EM408 uses a 5-pin cable and is not compatible with the 6-pin cable included with the EM406.

Not sure which GPS module is right for you? Check out our GPS buying guide!

  • 20-Channel Receiver
  • Extremely high sensitivity : -159dBm
  • 10m Positional Accuracy / 5m with WAAS
  • Hot Start : 8s
  • Warm Start : 38s
  • Cold Start : 42s
  • 75mA at 3.3V
  • 20gram weight
  • Outputs NMEA 0183 and SiRF binary protocol
  • 35mm x 36mm

GPS Receiver - EM-408 SiRF III (20 Channel) Product Help and Resources

Core Skill: Programming

If a board needs code or communicates somehow, you're going to need to know how to program or interface with it. The programming skill is all about communication and code.

2 Programming

Skill Level: Rookie - You will need a better fundamental understand of what code is, and how it works. You will be using beginner-level software and development tools like Arduino. You will be dealing directly with code, but numerous examples and libraries are available. Sensors or shields will communicate with serial or TTL.
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Core Skill: Electrical Prototyping

If it requires power, you need to know how much, what all the pins do, and how to hook it up. You may need to reference datasheets, schematics, and know the ins and outs of electronics.

3 Electrical Prototyping

Skill Level: Competent - You will be required to reference a datasheet or schematic to know how to use a component. Your knowledge of a datasheet will only require basic features like power requirements, pinouts, or communications type. Also, you may need a power supply that?s greater than 12V or more than 1A worth of current.
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Looking for answers to technical questions?

We welcome your comments and suggestions below. However, if you are looking for solutions to technical questions please see our Technical Assistance page.

  • sblaszak / about 14 years ago / 2

    This unit uses a Sirf-III GPS chipset has a limitation that buyers should know about. THIS UNIT WILL NOT WORK AT AN ALTITUDE OVER 18000 METERS (60000 FEET). This doesn't matter to most people, but is important to hobbyists that take part in high altitude weather ballooning, amateur rocketry, etc. Someone I know mistakenly purchased a Sirf-based unit for ballooning and I'm hoping to save people from making the same mistake.
    I'm going to post this in the comments section of all the Sirf-based Sparkfun products in the hope of saving someone from from making the same mistake. I apologize if the Sparkfun guys consider this spamming, that isn't my intent. It, also, isn't my intent to drive business away from Sparkfun. They have an awesome collection of GPS products and many of the other modules don't have this limitation.

  • TroyLanes / about 16 years ago / 2

    This is a great module. Great time to first fix! I wish sparkfun stocked extra cables, however, you can buy extra cables at:

  • Member #50653 / about 13 years ago / 1

    Question: who has experience with the external antenna of the 408?

    Normally I use the EM406. Recently I installed a unit in a building with hardly GPS signal. I got no strings; outside the building it worked fine. I changed over to the 408, connected the external antenna and installed it outside. No signal. I placed the whole unit outside and voila, it worked immediately. So I have the strange feeling the external antenna does not have any effect. I cannot find a command in the Globalsat manual to force the EM408 to use the external antenna so I presume that it uses both the internal and the external as the latter is connected.

  • Member #253805 / about 13 years ago / 1

    It is said from the website that, this GPS module could be used either using its built-in patch antenna or an external antenna, but how could I figure out which antenna is working if I have connected the external antenna. I only want to make sure the external antenna is working, but if two antennas that would make me feel confused.

  • Member #39993 / about 13 years ago / 1

    Datasheet link is broken, here is the new one:

  • Gulopine / about 14 years ago / 1

    I'm looking at this unit because the Ultimate IMU supports it directly, but I'm afraid my intended usage won't allow the built-in ceramic antenna to be pointed up properly. The descriptions mention an MMCX jack for an external antenna, but are there are any related products or recommendations for available antennas that will work with this module?
    EDIT: Never mind, I just noticed the MMCX to SMA cable in the related products. I just hope Sparkfun gets more in stock.

  • vickiro / about 15 years ago / 1

    Hi guys,
    I want to connect this GPS module to my beagle board.
    Beagle board website is
    Does anyone know how to connect it?

  • vickiro / about 15 years ago / 1

    Hi guys,
    Are there any evaluation board with I2C interface that fits this EM 408 module?

  • SteveMajor / about 15 years ago / 1

    This device works beautifully. We hooked it up--indoors with no window for giggles--and it immediately got a 3d fix from 5 satellites with the on-board patch antenna alone. It should work even better outside. Some things not in the data sheet--tie both enable and RX to 3.3 V and the output is defaulted to 4800 baud 8,n,1. Our senior design group is very happy with this module. Another group is also having success with the EM-406A module.

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