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Recently my GPS has poor reception

Discussion in 'Phantom 2 Vision + Help' started by erkme73, Oct 20, 2015.

  1. erkme73

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    The last couple of times I've taken my P2V+ out, the GPS seems to take forever to get a lock. It's gotten to the point that I take off and hover at 20-30 feet. Initially I'll have zero sats. After a minute or two it'll go to 5. But w/o 6, there's no lock, and it'll just slide around everywhere. If I'm lucky, it'll pop to 6 or maybe 8, but as I'm flying, it'll regularly drop back to 5 (red).

    It's entirely stock, never crashed, never been wet. It's been at least 6 months since I last had it connected to a PC for any kind of updates - and was working find after doing so.

    I've recalibrated the compass after moving between TN and FL on a couple of trips, but still, same results.

    I've never opened the shell, but and thinking maybe I should to see if something has come loose?
     
  2. Davowalshy

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    Maybe the connection from your GPS to the board is a bit loose. You can crimp the connectors to tighten them up and reposition your gps cord under the stock shielding as well. Also I did the foil shield and I get up to 10-11 sats in a minute or two. Works great.
     
  3. erkme73

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    Thanks @Davowalshy. Shortly after posting, I found the well-written thread on how to open and shield the GPS sensor with foil. Having no copper tape, I made a quick proto-type with some aluminum foil tape (duct tape) and that improved the signal to between 6-8. It also never dropped out again after locking. Definitely something going on with interference between components.

    I've got the copper foil on order, and will apply that as per the write-up.
     
  4. Davowalshy

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    Nice one. After I did the mod I couldn't believe how well it worked for me. I'm only using the foil covered with a piece of paper to stop shorting. Yep. The camera apparently messes with the signal as well. Simon Newton "The Kitchen Table" on you tube always plenty of fixes and great info as well.
     
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  5. kirk2579

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    the alum tape you are using is fine no need to change it to copper it wont add any more.

    however, you would benefit a lot by swapping out the gps antenna part on the module. It takes under an hour and less than $10.

    That with the mod you already did will definitely get faster, and better GPS lock
    http://www.digikey.com/product-detail/en/CGGP.25.4.A.02/931-1126-ND/2690283
     
  6. erkme73

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    Will that work for US/DOD GPS or is this specific to the Russian Glonass GPS?
     
  7. kirk2579

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    Good for phantom , it covers the frequency range used by both systems and has 5 db gain. Been using in my plus since about Feb. Could not get a lock sometimes for 3 or 4 minutes and even then finicky.

    Much faster and once it locks it is pretty solid staying so!

    Good luck and have fun flying!
     
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  8. erkme73

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    A huge thank you. I have ordered it from Digikey and will report back here once it's received an installed.
     
  9. kirk2579

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    would be extra nice if someone could adapt the newer GPS / Glonass chips to the phantom module, like the P3
     
  10. erkme73

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    Well, I gotta say, I'm impressed with how fast digikey got the GPS antenna to my door. It arrived today, and I've installed it. Very simple to remove the old one, and solder the new one one.

    One thing I didn't realize (or read in any of the other threads) is that this new GPS ceramic antenna is about 2x thicker than the original one. That meant when screwing the entire board back onto the shell, the antenna was actually making contact with the plastic shell. It looks like some of the shell could be cut away, but the circular ribs look like they give it some strength. So, I opted to simply not screw down the four screws all the way. It's snug, but not super tight. No doubt if I ever crash this upside down, it will very likely snap that new antenna.

    I applied new aluminum foil duct tape, and made sure to get as much of the wiring under the foil. I fired it up, and within a minute, I had 6 sats inside the house. I took it outside, and about a minute later, I had 8. It peaked at 9 while in flight. Definitely better, but not the double-digit count I was expecting. Still, well worth the effort - especially if it keeps it from flying away.
     
  11. kirk2579

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    6 inside house, your good to go!
    its not so much how many, but how fast they lock and how solid the lock stays.
     
  12. Mark The Droner

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    So let me get this straight.

    The Glonass antenna here:

    http://www.digikey.com/product-detail/en/CGGP.25.4.A.02/931-1126-ND/2690283

    ...is just as good or better than the GPS antenna here...

    http://www.digikey.com/scripts/DkSearch/dksus.dll?Detail&itemSeq=180847040&uq=635812645289789874

    ...?

    Is that right?

    If so, do we know why that is?

    Re the plastic ring inside and around the antenna, I agree it adds strength to the shell and also helps keep the antenna nice and snug so that any sudden crashes would be less likely to break the ceramic loose from the board. Nonetheless, I ground off that ring and some of the surrounding walls near the ring so that it was flat. I figure it's a five dollar part if it breaks. I thought removing some of that plastic might aid in reception. Since then, I don't have trouble getting GPS, the satellites seem to lock faster, but I can't be absolutely sure if it actually helps.
     
  13. kirk2579

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    The 1126 antenna in not Glonass per sea: It is GPS/GLONASS, the antenna is tuned for the bands both use, They have a new one out now that covers GPS/GLONASS/BEIDOU

    If you are asking me , I have no idea! The link comes up 404.

    Other antennas are available as well by other mfg and Toaglas that work fine.

    In fact My P2V1 has a 931-1015-nd I installed a week before the 1126 in my Plus.

    They both acquire sat lock and hold it much better than old antennas.
    Nite and day difference for me in Ohio


    here's info on 1126, Note APPLICATIONS and GAIN

    CGGP.1600.25.4.A.02 Spec
    Product Photos CGGP.25.4.A.02
    Standard Package [​IMG] 200
    Category
    RF/IF and RFID
    Family
    RF Antennas
    Series -
    Packaging [​IMG] *
    Frequency Group UHF (1 GHz ~ 2 GHz)
    Frequency (Center/Band) 1.6GHz
    Frequency Range 1.575GHz ~ 1.61GHz
    Antenna Type Ceramic Patch
    Number of Bands 1
    VSWR 1.5
    Return Loss -
    Gain 5dBi
    Power - Max -
    Features -
    Termination Solder
    Ingress Protection -
    Mounting Type Adhesive
    Height (Max) 0.157" (4.00mm)
    Applications GLONASS, GPS
    Online Catalog Taoglas Limited - Embedded
    Other Names 931-1126
    CGGP.1600.25.4.A.02
    CGGP254A02
     
    #13 kirk2579, Oct 24, 2015
    Last edited: Oct 24, 2015
  14. Mark The Droner

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    Okay sorry for the 404 thing. I blame the internet. It's part number 931-1015-ND and if you put that in the search box on the site it comes up. It's a GPS antenna which somebody posted on here a while back.

    Thanks for the help.
     
  15. kirk2579

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    Both of those part numbers seem to work about equal however I am not running 3.14 in either quad.
    Around Feb I updated both the P2v1 and plus about a week apart(was not sure which antenna was best I ordered both). Once I saw how much better the first upgrade worked I installed the second antenna (1 a -1015 and 1 a -1126).

    Initially I would say the plus with the 931-1126-nd seemed quicker to acquire of the 2, both went from minutes and minutes to about 40 to 60 seconds for gps to set home.

    However after I upgraded the plus to 3.12 it appeared to me to take much longer to acquire than on 3.08, still faster for sure.

    Side by side the P2v1 with 1015 antenna is now 10 to 20 seconds faster to acquire lock than the plus with 3.12 and the 1126.

    I believe the difference is the firmware modified gps specs, thus I am staying at 3.08 until......


    good luck and have fun flying!
     
  16. RoyVa

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    Changing its GPS antenna puck is not going to allow getting additional GPS bands. It would take changing out the entire GPS module and a software update to get the added bands. As the ole saying goes it is what it is. Changing the puck antenna to a higher level dbi antenna just give better reception on the band it already has. May pick up the satellites faster and add one or two more for lock improvement but not added bands.
     
  17. Mark The Droner

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    Yeah it would.

    I believe the Advanced and Pro do have Glonass capability, but not the Standard.
     
  18. jwax

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    Check out Digikey P/N 931-1315-ND. It will receive GPS, GLONASS, and Beidou. Some shell modification required.
     
  19. N017RW

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    That is just an antenna.

    You need the proper GPS engine to have the multi-constellation capability.
     
  20. jwax

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    Indeed. Does the stock GPS engine on the P2V+ have that capability?