Welcome to PhantomPilots.com

Sign up for a weekly email of the latest drone news & information

Question about Radio, uplink, downlink, frequency, & telemetry

Discussion in 'Standard/4k Discussion' started by gklugie, Apr 26, 2016.

  1. gklugie

    Joined:
    Dec 12, 2015
    Messages:
    146
    Likes Received:
    50
    Location:
    Dallas, Texas
    I have a Phantom 3 Standard, and have not been able to fully understand the communications loops on my device. My guess is this:

    Controller transmits signals (uplink?) to aircraft via single external antenna..... on 5.8 Gig frequency
    Aircraft sends signals (downlink?) to controller's internal dual flat antennas .... on 2.4 Gig frequency
    Aircraft sends signals to my android tablet via wifi ....on 2.4 Gig frequency
    Tablet sends signals to aircraft via wifi ... on 2.4 gig frequency (does tablet transmit directly to drone?)

    Does it work like this? ........ Am I close?

    Additionally, which of the above communications links benefits from a parabolic (wind surfer) antenna add-on?

    (just wondering)
     
  2. SamNetwork

    Joined:
    Apr 9, 2016
    Messages:
    479
    Likes Received:
    85
    Location:
    Ronald McDonald Land
    First part was correct, but after that you kinda messed up.
    Control: Controller➡️Aircraft (5.8ghz)
    Video Downlink: Aircraft
    ➡️Controller (2.4ghz)
    Device Video Downlink: Controller
    ➡️Device (2.4ghz)
    Device Control: Device➡️Controller (2.4ghz)
    The Controller makes it's own WiFi Network, the device doesn't communicate directly with the aircraft.
     
    Warren Dean likes this.
  3. gklugie

    Joined:
    Dec 12, 2015
    Messages:
    146
    Likes Received:
    50
    Location:
    Dallas, Texas
    Thanks. I presume that "device" = the smartphone/tablet.

    Now, which antennas are associated with which functions? ( stick antenna, plus the internal 2 paddle antennas onside the controller)
     
  4. gklugie

    Joined:
    Dec 12, 2015
    Messages:
    146
    Likes Received:
    50
    Location:
    Dallas, Texas
    correction... the paddle antennae are inside the controller.
     
  5. finalfantasyfan

    Joined:
    Feb 14, 2016
    Messages:
    223
    Likes Received:
    76
    Location:
    Dallas, TX
    Stick is 5.8ghz and the 2 internal one are 2.4ghz. P3S aircraft uses 2.4ghz downlink video to the controller using WiFi. For P3P/A, the aircraft also uses 2.4ghz but using Lightbridge. Lightbridge is a one way broadcast communication which doesn't require packet resend if a byte is lost. Wifi requires two way handshake so if a byte is dropped, the whole 512 byte in the packet has to be resent. That's why P3P/A has much better live video feed.


    Sent from my iPhone using PhantomPilots mobile app
     
    firestars likes this.
  6. Mako79

    Joined:
    May 16, 2014
    Messages:
    3,413
    Likes Received:
    567
    Location:
    Sydney Australia
    External white antenna is 5.8ghz 1 way uplink transmitter only. This is all the analogue movements on your controller. Eg flip switches and control sticks.

    Internal 2.4 antenna is a patch 2.4ghz 2 way communications via traditional wifi. When you press buttons on your screen like taking a photo, it uses the 2.4 ghz wifi to send instructions UP to the P3Std. When you are looking at the sat/bat telemetry it is using the DOWN link to receive data. And obviously, FPV is also using the DOWN link.
     
  7. Omokjoe

    Joined:
    Jan 12, 2016
    Messages:
    56
    Likes Received:
    7
    Very interesting. Most of us know how to use this technology , but don't know how the technology works ! I'm still not sure of the linkage for GPS signals ? ? Is it OK to stand under a tree ( for shade ) for GPS reception - with quad in front of tree in los.


    Sent from my iPad using PhantomPilots mobile app
     
  8. Mark The Droner

    Joined:
    Aug 26, 2015
    Messages:
    3,973
    Likes Received:
    1,160
    Location:
    Brookeville, MD, USA
    Yes you can stand under tree provided aircraft is out in the open at least somewhat. But you might find your own fix for your device is bouncing around a bit.
     
  9. Omokjoe

    Joined:
    Jan 12, 2016
    Messages:
    56
    Likes Received:
    7
    Thanks I thought so. Still not sure how GPS works ! Does quad pickup GPS direct relay back to tablet/phone or per controller ?
     
  10. Mark The Droner

    Joined:
    Aug 26, 2015
    Messages:
    3,973
    Likes Received:
    1,160
    Location:
    Brookeville, MD, USA
    The one thing I am not sure about is how, like exactly, does the data move from the controller to the mobile device. My understanding is, the data is relayed on a different wifi freq. That's fine, but what transmitter is used? There are two transmitters. What about switching? Does it use either transmitter and is completely random depending on what's going on?
     
  11. Mark The Droner

    Joined:
    Aug 26, 2015
    Messages:
    3,973
    Likes Received:
    1,160
    Location:
    Brookeville, MD, USA
    The GPS data is sent to the mobile device just like all the other telemetry data as described in multiple posts above.

    How does it work? That's a little more involved.

    ...

    How does GPS work?| Explore | physics.org
     
  12. RodPad

    Joined:
    May 20, 2015
    Messages:
    2,637
    Likes Received:
    365
    Location:
    Pacific,NorthWet, 97031
    When you press buttons on your screen? Your sending instructions UP to controller, then controller sends it to the bird, Correct?
    This is why I don't rely on the RTH button on the device to actually activate RTH.
     
  13. RodPad

    Joined:
    May 20, 2015
    Messages:
    2,637
    Likes Received:
    365
    Location:
    Pacific,NorthWet, 97031
    If read your post correct, that answer is on post#2, it creates its own wifi network.
     
  14. RodPad

    Joined:
    May 20, 2015
    Messages:
    2,637
    Likes Received:
    365
    Location:
    Pacific,NorthWet, 97031
  15. Mako79

    Joined:
    May 16, 2014
    Messages:
    3,413
    Likes Received:
    567
    Location:
    Sydney Australia
    If you trigger RTH on the physical controller, it is sent via the 5.8ghz antenna > 5.8ghz receiver board > main board > NAZA.
    If you trigger RTH on the screen, it is sent via the 2.4ghz patch antenna > 2.4ghz wifi module > main board > NAZA.
     
  16. RodPad

    Joined:
    May 20, 2015
    Messages:
    2,637
    Likes Received:
    365
    Location:
    Pacific,NorthWet, 97031
    So was I correct? That is why the button on the app my not actually work, if the app happen to fail sending the command via Wifi to the remote?

    I guess the other confusion is either way if RTH was initiated, but the signal coming back from the bird is lost, the app doesn't display RTH is activated.
     
  17. Mark The Droner

    Joined:
    Aug 26, 2015
    Messages:
    3,973
    Likes Received:
    1,160
    Location:
    Brookeville, MD, USA
    The nice thing about turning off your controller is you KNOW Rth is activated. You don't have to worry. Just relax and pop a beer
     
  18. RodPad

    Joined:
    May 20, 2015
    Messages:
    2,637
    Likes Received:
    365
    Location:
    Pacific,NorthWet, 97031
    Yes I have done that, both ;), but then you loose your flight log, so that is the my last choice, but in about 5 second window.:eek:
     
  19. gklugie

    Joined:
    Dec 12, 2015
    Messages:
    146
    Likes Received:
    50
    Location:
    Dallas, Texas
    Hmm... so what is the benefit of a wind surfer parabolic antenna device if it only improves the outgoing signal?
     
  20. garrock

    Joined:
    Apr 29, 2014
    Messages:
    466
    Likes Received:
    47
    Location:
    Portsmouth Ohio USA
    I found a way to remove the internal WiFi Module inside the P3S Controller and house it in an external enclosure with its own battery. No soldering or wire cutting.

    Along with the REDbird 5.8ghz RC Repeater Module, that makes a complete repeating solution for the P3S.

    Mount both ontop our car and sit comfortably inside wile maximizing your range.
    Two man team: car driver and drone operator.

    Or mount the repeater pair on a second Repeater-Helper Drone and let it over over head.