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Antenna plug on back of Captivate.

Discussion in 'Android Devices' started by cdsiemer, Aug 11, 2010.

  1. cdsiemer

    cdsiemer Lurker
    Thread Starter

    I noticed what looks like an antenna plug on the back of the phone. Anyone know what this is for? It looks like a wifi plug like the ones in laptops.

  2. jmreed97

    jmreed97 Well-Known Member

    It is an MMCX plug... It is either for wifi, cell, or GPS. I am hoping GPS and I have ordered a GPS antenna with an MMCX plug that should get to my house by Friday.

    I will plug it in and let everyone know what happens when I get it.
  3. Loremonger

    Loremonger Well-Known Member

    Where are you seeing this? All I got is the speaker slits.
  4. Bearsyzf

    Bearsyzf Android Expert

    where do you see that at, all i see is the speaker and the camera lens ?
  5. MikeyMike01

    MikeyMike01 Member

    It's under the battery cover, near the SIM card.
  6. sremick

    sremick Android Expert

    While I adore the idea of an external antenna plug (in fact, the Captivate is my first phone to not have one I can use), I cannot fathom the point of putting it behind the battery cover. Who's going to use their phone without a battery cover so that they can plug in the antenna???

    Note: plugging in an external antenna that sits on the roof of your car, outside of the glass and metal, makes a gigantic difference in reception.
  7. sonorous

    sonorous Newbie

    I am not sure what the connector is for but I can say with 100% confidence that it is not an MMCX connector. I am an engineer with a company that manufactures connectors.

    I can say that it is a switching type connector and there are many interfaces in this category. This means that the signal normally passes through it, typically to an internal antenna, until it is mated to, then the signal passes through the mating connector. The most common use for these connectors is end of line testing at the factory. It is possible that an external antenna could be connected through this port but one would have to test that by trial and error. It is surely not convenient being under that battery cover.
  8. roadhawg00

    roadhawg00 Lurker

    I saw it too, I also have a Tundra and under the battery cover there is a small rubber plug, when you remove it there is a small connector. I have saw posts that show people cut a small hole in the cover and plugging an antenna connector into that hole. They all said it was an antenna connector and they showed a jump in signal. No I never tried it and no it's not worth chopping on my baby. I tend to believe the testing connector. Either I love this thing too much to screw it up.
  9. Rred

    Rred Member

    Samsung's tech support just informed me that it "Absolutely, positively" is an MPX connector for an external antenna for the phone. Not the GPS, the phone.

    And that they have no other battery covers, either you have to make a hole in a spare cover, or use some other cover for the phone.

    But they swear it is a fully functional external antenna plug, MPX female, needs an MPX male on the cable to plug into it.

    External antennas do wonders for cell phones. In cars, offshore, in the boonies...
  10. ewingr

    ewingr Android Enthusiast

    Too bad. I"m thinking the GPS will never be worth much due to poor GPS antenna.
  11. Rred

    Rred Member

    Not poor GPS antenna, and an external GPS antenna defeats the purpose o fhaving a GPS *in* the phone.

    The poor GPS reception may be from a bad design of the GPS circuit (from Broadcom) which is normally all-in-one with a patch antenna included. Or it may be from RFI due to the phone's other radios. That's very possible. Or the portion of the phone's case that is over the GPS antenna may be radio-opaque.

    There could be many reasons for the poor performance and it may only take a "minor" production change to address that. Samsung probably will have to be shamed and embarrassed into correcting it, since they apparently don't have the pride to fix it.

    So let's all make up t-shirts that say "Korea must be closer to heaven, because Samsung GPSes can't reach the sky from anyplace else."
  12. reinbeau

    reinbeau Klaatu barada nikto

    I've got a GPS antenna on top of both vehicles. I remember the wailing and gnashing of teeth over the GPS when the iQue made its debut. I just bought the antennas and made it a nonissue. I'd love to be able to plug in an antenna and see if it would solve the GPS issue at least in the car - where I'd use it the most.
  13. GreatBigDave

    GreatBigDave Member

    I wonder if it's possible to have a GPS antenna that then can transmit its signal to your phone wirelessly? I seem to remember add-on cellular antennas back in the day that did not require a wired connection to your phone. That, or perhaps the crack is particularly sweet this afternoon.
  14. PGP_Protector

    PGP_Protector Well-Known Member

    Bluetooth GPS Antenna.
  15. ewingr

    ewingr Android Enthusiast

    on the Captivate, I'm not sure how that would be used but may be an option to have decent working GPS on the phone.
  16. ulbonado

    ulbonado Member

    Note that that's not just an antenna-- it's a whole separate GPS receiver.
  17. ulbonado

    ulbonado Member

    I believe you go to "Settings->Applications->Development" and check the "Allow mock locations" button. Then the external GPS unit can feed its data to the phone over bluetooth, and the phone will use that data instead of its internal GPS. Have not tried this myself, but that's my understanding.
  18. skramblr

    skramblr Well-Known Member

    Search for "Re-radiating antenna"
  19. Rred

    Rred Member

    "I wonder if it's possible to have a GPS antenna that then can transmit its signal to your phone wirelessly?" Once it transmits, it isn't just an antenna. I suspect a "reradiating antenna" would be like one of the magic passive antennas they used to give away that you stick on the back of your phone to make it work better. (Snake oil, since you can't get any signal gain that way, without adding power.)

    Once you start with magic antennas, you might as well spend $25-50 and buy a Bluetooth GPS, a complete GPS "in a stick" that transmits to your phone via Bluetooth. About $50 will buy a 3rd-generation SirfStar like that, but isn't that a waste, buying a whole new GPS because the one in the phone doesn't work? That's how you add GPS to a ten year old cell phone that never had it.
  20. jeremytanner

    jeremytanner Well-Known Member

    Back on the original topic, where would one get an antenna with an mpx connector? I'm not that familiar with antenna connectors, but out in the rural areas here I'd be willing to give it a try.
  21. reinbeau

    reinbeau Klaatu barada nikto

    Gilsson is the manufacturer I've always used.
    jeremytanner likes this.
  22. jeremytanner

    jeremytanner Well-Known Member

    So is MPX a mistype for MCX? If so, that would seem to indicate that the connector is a GPS antenna connector, right?

    Sorry if I'm making this confusing, I don't really know much about antenna connection standards.
  23. Rred

    Rred Member

    Jeremy, look around for anyplace selling cell phone antennas. See what connector is on the cable, it will probably be an "FME" connector. (Male, female, I don't recall offhand which.) Then if you're lucky the same place will sell mating FME-to-MCX connectors, either a pigtail or a metal adapter. A right-angle pigtail so it can lay flat against the back of the phone would be best.

    And yes, these are the standard "GPS external antenna" connector. Mainly because of the frequency and cable characteristics involved, nothing to do with GPS except that it uses a similar frequency and cable to what cell phones use. Samsung could have used FME or other connectors on the phone, or like Apple, none at all.<G>
  24. sonorous

    sonorous Newbie

    I will reiterate for the sake of saving you some money. I am an engineer with a very large connector manufacturer. Not a company like Gilsson but one that actually makes the connector. I can tell you with 100% certainty that the connector in question is not any standard interface. This includes MCX, MMCX, FME and all other standard interfaces listed on Gilsson.

    I would recommend going the Bluetooth route. The cost is about the same and it is much more likely to work. Otherwise you are likely to end up with a big pile of antennas, none of which will mate to your phone.
  25. Rred

    Rred Member

    "I can tell you with 100% certainty that the connector in question is not any standard interface. "
    Except, Samsung support says it is MCX. If it is not MCX, what is it?

    The "bluetooth route" would be to replace the internal GPS with an external functioning one. The antenna connector and external cellular antennas has nothing to do with that. The purpose of the antenna connector (assuming that Samsung wasn't mistaken about what it is) is to improve cellular service. Nothing to do with GPS.

Samsung Captivate Forum

The Samsung Captivate release date was July 2010. Features and Specs include a 4.0" inch screen, 5MP camera, 512GB RAM, Hummingbird processor, and 1500mAh battery.

July 2010
Release Date

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