Welcome to PhantomPilots.com

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

Judging distance over water - not easy!

Discussion in 'Pro/Adv Discussion' started by Erroll, Jan 25, 2016.

  1. Erroll

    Joined:
    May 15, 2015
    Messages:
    501
    Likes Received:
    212
    Location:
    South Africa
    I recently did a long distance flight out to sea to try and film a passing container vessel. As far as I could recall one can see close to 5km from sea level looking out to the horison, and having done 5km flights before, I thought that this would be doable.

    I lost sight of the ship on my iPad and had to change course 2/3rds of the way out to get back on track, because I had not been compensating for the ship's speed. After 5.3 km my quad was not even close to the ship and I turned back. Quite difficult to judge distance over the water with no reference points.

    The first picture below is a frame grab from just before I turned around (5.3km out) - one can hardly see the ship.
    The second picture is of the coast line after I had turned around - adrenalin-pumpingly far away!

    Ship.JPG

    CoastlineSnapshot.jpg

    Another observation: - I had only one slight RC signal glitch (which I only saw after having uploaded the log to HD), but my video signal dropped several times during the sortie. I had set out at about 100ft ASL because the whole flight was going to be LOS, but even going up to about 300ft made little difference. Every few minutes my video signal would drop. Does the water have an effect on the video signal, but not the radio signal?
    (Here is the HD link for those interested: HealthyDrones.com - Innovative flight data analysis that matters )
     
  2. happydays

    Joined:
    Jul 5, 2013
    Messages:
    1,858
    Likes Received:
    663
    Location:
    Warrenpoint, Ireland
    I would have thought that height would have increased the signal strength - maybe not?
     
  3. Wacker2611

    Joined:
    Sep 10, 2015
    Messages:
    444
    Likes Received:
    164
    To be fair and depending on what if any antenna mods you have, I think that's a pretty satisfactory distance to keep full control. It was only a minor glitch, and you were 5km away!
     
    ELHEAPO likes this.
  4. Erroll

    Joined:
    May 15, 2015
    Messages:
    501
    Likes Received:
    212
    Location:
    South Africa
    Yes, I thought so too.

    I was too absorbed with being so far out over the ocean that I completely forgot about my windsurfers. It would have been a good test to employ them to see if they would have made any difference in that scenario.
     
  5. Erroll

    Joined:
    May 15, 2015
    Messages:
    501
    Likes Received:
    212
    Location:
    South Africa
    Interesting.
     
  6. Erroll

    Joined:
    May 15, 2015
    Messages:
    501
    Likes Received:
    212
    Location:
    South Africa
    I was flying a completely stock standard RC - no mods, and I am not complaining about the distance at all! I have done several 5km+ flights before and am supremely confident in the equipment.

    I was just curious as to the loss of video signal over the water.
     
  7. happydays

    Joined:
    Jul 5, 2013
    Messages:
    1,858
    Likes Received:
    663
    Location:
    Warrenpoint, Ireland
    I wonder why I'm not seeing the original post from MapMaker53?
     
  8. Meta4

    Meta4 Moderator
    Staff Member

    Joined:
    Jan 8, 2014
    Messages:
    7,767
    Likes Received:
    3,475
    Wow .. 5km is a long way to go offshore and you'd definitely want to make sure you're not going to be pushing a headwind coming home from out there.
    If you are chasing ships, it pays to find somewhere they approach closer than 5km.
    With a little practice you can work out when to launch to intercept at a suitable point.
    Ships are great subjects and shots of them at sea can be pretty special.
    [​IMG]

    To help you with ships and distances, get an app for your phone called Marinetraffic.
    That will show you where the ships are, how fast they are traveling and you can use the scalebar to estimate distance or they have a function to calculate how far using the GPS in your phone.
    Here's a screenshot:
    [​IMG]
     
    snowghost and Erroll like this.
  9. Erroll

    Joined:
    May 15, 2015
    Messages:
    501
    Likes Received:
    212
    Location:
    South Africa
    Thank you. That is very informative.

    Alas, I am from Johannesburg and only very seldom get to fly at the coast.

    I am curious - your screen shot is of Durban?
     
  10. dirkclod

    dirkclod Moderator
    Staff Member

    Joined:
    May 9, 2014
    Messages:
    10,687
    Likes Received:
    5,713
    Location:
    Amory Mississippi
    He might have been deleting his post as it was being quoted happy . Have had that done before .
    Tried to delete and got caught :)
     
  11. happydays

    Joined:
    Jul 5, 2013
    Messages:
    1,858
    Likes Received:
    663
    Location:
    Warrenpoint, Ireland
    Good answer. Thought I'd been blocked!
     
    dirkclod likes this.
  12. Erroll

    Joined:
    May 15, 2015
    Messages:
    501
    Likes Received:
    212
    Location:
    South Africa
    I can't imagine why he would not want that post to be quoted.....?

    :rolleyes::rolleyes:
     
  13. dirkclod

    dirkclod Moderator
    Staff Member

    Joined:
    May 9, 2014
    Messages:
    10,687
    Likes Received:
    5,713
    Location:
    Amory Mississippi
    I don't ether but was just saying I have had that happen before .
     
  14. CCDD

    Joined:
    Nov 20, 2015
    Messages:
    650
    Likes Received:
    384
    Location:
    US
    Perhaps I'm a bit confused, how can one fly LOS if their Phantom is out 5km +? Doesn't LOS mean you still have a visual of your bird? I don't believe one could possibly see their Phantom from that far away unless they're using binoculars or something similar.
     
  15. dirkclod

    dirkclod Moderator
    Staff Member

    Joined:
    May 9, 2014
    Messages:
    10,687
    Likes Received:
    5,713
    Location:
    Amory Mississippi
    You mean VLOS . LOS is between your TX and RC .
     
  16. CCDD

    Joined:
    Nov 20, 2015
    Messages:
    650
    Likes Received:
    384
    Location:
    US
    Ahh, thanks for the explanation. I meant VLOS, and the op was referring to LOS. My bad
     
  17. dirkclod

    dirkclod Moderator
    Staff Member

    Joined:
    May 9, 2014
    Messages:
    10,687
    Likes Received:
    5,713
    Location:
    Amory Mississippi
    No problems ..I have a lot of bad's :)
     
  18. Solar Deity

    Joined:
    Nov 29, 2015
    Messages:
    268
    Likes Received:
    144
    Location:
    Upstate NY
    I'm bored, and in to making graphics today.

    SD VLOS.jpg
     
    Meta4 likes this.
  19. CCDD

    Joined:
    Nov 20, 2015
    Messages:
    650
    Likes Received:
    384
    Location:
    US
    Helpful!!
     
  20. Erroll

    Joined:
    May 15, 2015
    Messages:
    501
    Likes Received:
    212
    Location:
    South Africa
    Eish! I could hardly see a container vessel at that distance!!

    :p:p:p:p