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Inside the Yaesu VX-8r GPS module (FGPS-2) & pinout information

Discussion in 'Ham Equipment' started by Moleculo, Jan 6, 2010.

  1. Moleculo

    Moleculo Administrator
    Staff Member

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    Today I decided to crack open the optional GPS module FGPS-2 for the VX-8r to see what was in there. Of course, I took pics for everyone to see.

    Here is a pic of the Yaesu VX-8r with the optional GPS and mounting bracket (CM-136) attached to the radio:

    [​IMG]

    There are two very small screws on the back of the GPS unit that allow you to crack it open. Here's what it looks like on the inside:

    [​IMG]

    You can see that the unit is sealed with a green rubber gasket to waterproof it. Even the screws have little plastic washers on them to keep the moisture out.

    Here is a closeup of the top of the GPS module:

    [​IMG]

    And here is a closeup picture of the back:

    [​IMG]

    The markings on the top right of the back side are:
    GPS72A(C)042
    LTM0838

    The bottom right has a board number: P08-700C. The bottom left looks like a part number: PN-042A. I tried in vain to google all of these numbers to find out more information about this module. Perhaps someone else will recognize it. I DID find out by going through the specs that this is a 12 channel GPS receiver.

    Here is a picture of the mounting adapter. I'm holding the front of the adapter toward my body and then tilting it forward for the pic. I've labeled the pin numbers in the picture:
    [​IMG]



    The GPS unit only uses 5 of these pins. Here is the information I was able to scrounge up on the pinout for these pins:

    5 – 3.3v
    6 – GPS RXD
    7 – GND 13 – GPS TXD
    14 – Not used


    You can cross reference the pinout of the GPS unit against the radio's speaker/mic connector here:


    http://www.worldwidedx.com/handitalkies/39105-yaesu-vx-8r-mic-gps-cable-pinout.html
     

  2. C2

    C2 Sr. Member

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    way cool...i could not identify the gps module either...
     
  3. VA3xxx

    VA3xxx Member

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    I did manage to get the vx-8r i have to run with another module.

    The Navilock NL-507 ETTL will work. You need to set it up in Compatibility-mode, though. The VX-8's parser is pretty stupid and expects fixed numbers of digits in the NMEA sentences.

    one sentence i recorded was:
    $GPGGA,201613.000,4340.7221,S,07920.6194,E,1,00,1.0,134.6,M,-35.3,M,,*7D

    The VX-8 expects 9600 Baud NMEA,

    $GPGGA
    $GPRMC
    $GPZDA

    The Navilock unit cost me 35 Euro.
     
  4. C2

    C2 Sr. Member

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    Kazakhstan?
     
  5. VA3xxx

    VA3xxx Member

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    not quite. Spain or Italy. :whistle: just picked some random mumbers.

    National Marine Electronic Association - NMEA
    NMEA 0183 - Wikipedia, the free encyclopedia

    I haven't figured out yet how to get the height correct, but i guess this shouldn't be a problem.
    Anyway, OMs using APRS should know at least a faint bit about what NMEA 0183 is and how it works.

    We should be glad they didn't put in a navitra receiver, eh.
     
  6. KC7HP

    KC7HP Member

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    I hope some expert adds to this thread -- I'm looking at the FTM-350R, which can use the same GPS module, but would like to switch to a proper rooftop external GPS antenna.

    Another description of pin-outs on either end of a CT-M11 cable / CT-136 adapter may be found here: http://www.0xdecafbad.com/2009/09/vx-8-data-cable/
     
    #6 KC7HP, Apr 26, 2010
    Last edited: Apr 30, 2010
  7. aquaregia

    aquaregia Member

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    Probable manufacturer of GPS module

    I think the module is produced by Positions, Inc., a subsidiary of Chiyoda Electronic Company. Found this (probable predcesor of the unit in the Yaesu module)

    http://www.cec-chiyoda.co.jp/info/GPS_Rev1.pdf

    which lists the GPS-72A(B) 038 model number.

    They're on the GPS 75 series, so I'll poke around and see if I can find a datasheet for the GPS-72A(C) 042.

    Happy trails.
     
    #7 aquaregia, May 13, 2011
    Last edited: May 13, 2011
  8. aquaregia

    aquaregia Member

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  9. aquaregia

    aquaregia Member

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    And here is someone wrenching on one. I think they look identical, other than the bubble in the Position PDF.

    http://blog.yahoo.com/micomsys/articles/3
     
  10. aquaregia

    aquaregia Member

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    I opened mine up and this is what I found.
    In the upper left hand corner is a wire that wasn't in Moleculo's picture, and because of that I was scared to attempt to flip the module.

    I wouldn't doubt if they used GPS-72A(A-D) depending on manufacture date.

    If anyone finds that GPSVP program, let me know. It'd be nice to use the advanced functions of this reciever on the PC.
     

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  11. aquaregia

    aquaregia Member

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    Nope, the (B) and maybe (A) models run off coin cells, so I guess the (C) and maybe (D) were custom built for an application such as the FGPS-2.

    More questions than answers, I guess.
     
  12. aquaregia

    aquaregia Member

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