New GPS for NTP server

  • I have been using a Sure GPS now for many years.

    Built a new PFSense box here recently and purchased:

    1 - NEO-8M GPS Satellite Positioning Module for Arduino STM32 C51 replace NEO-7M (Ebay)
    2 - TTL RS-232 board and wired PPS to Pin #1 on RS-232

    Programmed the board using NMEA 4.0

    Configured in PFSense as a U-Blox / 9600 baud all sentences for time bean.
    I see the NMEA sentences fine via cat gps0.

    First time I connected it it worked fine and saw number of satellites et al.

    Then I played with the GPS some and now cannot see the satellite view.

    I do see the sentences that indicate number of satellites seen.

    Anybody using one of these?

  • Replying to my own post figured out (guessing mostly) the configuration with the Neo-8M GPS Satellite board U-Blox Windows programming software.


    Will post configuration used to make this work for me.

  • Thanks Pete: I for one am watching this thread with interest. :)

  • LAYER 8 Global Moderator

    I would think multiple people would be interested in a full write up of how to do this..

    You have to do some soldering I'm guessing to get this all connected?

  • Did do a short write up on another forum a while ago. The easiest part of this endeavor was soldering for the PPS signal.

    Original documentation used is located here for Sure GPS.


    PFSense computer:


    This was done for a family member. Doing another one here to replace my current PFSense box with 6 Intel Gb ports. This box should fit nicely inside of my Leviton Media panel (42"). Do a primary ISP connection here with a cellular modem failover. (network and phone line).

    Parts list:

    1 - GPS with PPS for time sync via serial port

    GPS with RS-232 with PPS - NEO-8M GPS Satellite Positioning Module for Arduino STM32 C51 $7.49 (Ebay)

    2 - GPS Antenna (optional)

    3 - TTL to RS-232 converter Amazon ($7.00)

    PPS configuration. Plug in to PPS pin on GPS and solder other side to RS-232 pin #1.


    4 - USB datablocker for powering up the GPS -

    Programming to the GPS is done via U-Blox software via USB cable which provides power and a serial connection to GPS.

    Download U-Center for Windows programming tool here:



    U-Center user guide:


    By default the GPS will output both on the USB port and Serial port. You can see both by using a USB to Serial device.

    Will post configurations and screens. It is only 3-4 adjustments.

  • @pete said in New GPS for NTP server:

    NEO-8M GPS Satellite Positioning Module for Arduino

    I have U-blox already due a dongle I have.. Nice to know.

    The pfsense widget though?? Is that automagically or did you make any changes?

    Thank Pete!

  • For PFSense you need to utilize a serial to TTL device and add a PPS line.

    The PFSense NTP serial settings are there and it did work out of the box until I tinkered with the programming software.

    I used a USB data blocker for powering the device.

    GPS ==> TTL to RS232 plus PPS ==> computer RS-232 port
    ==> USB ==> data blocker ==> PFSense computer USB port for power.

    Here is a splat of images for the configuration that I used and saved to the GPS.
    It gets a bit confusing as there are many settings. You just have to remember to send the settings to the GPS and save the configuration to the GPS so that it survives a reboot.

    Note changed the boot up baud rate to 4800 as I was using 19200 and it did not always work on reboot of PFSense box.


  • This post is deleted!

  • Initially when I installed the Sure GPS I put it in the attic of a two story home. Used a cat5e wire with RS-232 ends to it going to the basement "server room". Recently moved it such that it faced a basement window facing the south east. For setting up this GPS just had the antenna next to a door which faced south east and it worked great.

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