Welcome to PhantomPilots.com

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

My homemade range extender

Discussion in 'Phantom 2 Vision Discussion' started by Fred_C_Dobbs, Aug 21, 2014.

  1. Fred_C_Dobbs

    Joined:
    May 14, 2014
    Messages:
    26
    Likes Received:
    2
    Location:
    Crestview, FL
    I saw a reply to a post recently (which I cannot find) in one of the range extender threads where a guy said he made a reflector out of aluminum foil and mounted it behind the control antennae on his radio. A consensus seemed to develop that he was being less than truthful about the increase in range using his foil reflector. But, it got me thinking, maybe there was something to it. Here is my version:

    I printed a drawing of a parabola, then transferred that to some heavy stock paper and carefully cut out 2 pieces, which form the sides. The reflector is just the middle of a 12 oz soda can that I cut out using an old pair of (now very dull) scissors. To join the sides to the reflector, I used ordinary tape. I made a hole in the sides at the focus point of the parabola, extended the antennae a bit with a straw, then mounted and tested.

    To my complete astonishment, the thing actually worked! Without the reflector I was getting about 1500 feet before losing the control signal. With the reflector I can get nearly twice that (both tests under ideal, i.e. line of sight conditions). The one slight downside is the antennae seems to become somewhat directional with the reflector in place.

    I should also mention that I am using the RE700 wifi range extender instead of the one that came with my Phantom, so I have been able to maintain the FPV signal.

    Unfortunately, I do not have any 'proof' that it works this well, but it is very easy to make and doesn't cost anything, so I would encourage others to try it and see if you get similar results.

    \\FCD\\
     

    Attached Files:

  2. BWJ

    BWJ

    Joined:
    Aug 19, 2014
    Messages:
    144
    Likes Received:
    0
    Location:
    Denmark
    I guess you will have the opposite effect, just think how accurately dish should target TV satellites-
     
  3. John Shaw

    Joined:
    Mar 26, 2014
    Messages:
    198
    Likes Received:
    0
    Fred
    I know just enough about antennas to be dangerous and I think, step by step, your approach makes absolute sense. I am not surprised at your results and glad to hear it worked well. When you say "The one slight downside is the antennae seems to become somewhat directional with the reflector in place." This also is to be expected. I also think it is probably more than "somewhat" directional. As long as you keep the antenna/reflector pointed at the Phantom all is well. If the Phantom were to get behind you I would expect the signal is extremely weak as the reflector is focusing all the energy forward. However for missions where you need the reflector clearly you'll be keeping the Phantom in front of you. (or turn around).
     
  4. N017RW

    Joined:
    May 2, 2014
    Messages:
    6,236
    Likes Received:
    1,606
    Location:
    Palm Beach Co.- FL
    The polarity is at a minimum overlap in that position too.

    Ideally the antenna should be vertical that is to say parallel with the receiving antennas as much as possible.
     
  5. John Shaw

    Joined:
    Mar 26, 2014
    Messages:
    198
    Likes Received:
    0
    You are correct. The Phantom's receiving antenna is vertical and having the transmitter antenna horizontal does result in a measurable loss. Fred, it would be well worth testing with the transmitter antenna vertical (rotate you whole assembly) you should get even better results.
    (long ago I ran into this with a 20 mile microwave antenna link - the book said 3db loss if they weren't aligned and we confirmed it.)
     
  6. Fred_C_Dobbs

    Joined:
    May 14, 2014
    Messages:
    26
    Likes Received:
    2
    Location:
    Crestview, FL
    Re-testing with the radio antennae pointed straight up and the reflector on I hit about 2900 ft. Yesterday, under the same conditions but with the antennae sideways, I hit about 2700 ft.
     
  7. Dartmoor Dave

    Joined:
    Nov 14, 2014
    Messages:
    49
    Likes Received:
    1
    I've also been experimenting with a home made parabolic reflector for my 5.8 Mhz stub antenna and thought I was inventing a P2V+ wheel and then found this thread, so realised I was simply doing what others had done. I also thought about wavelength and adjusted the position of the stub so that the reflected wave was in phase with the non reflected forward wave.
    In my design, I used single sided aluminium foil sticky tape (3Ms) for ease of attaching it to the card I was using. Worked a treat as a directional antenna and I reached just over 1500 m ( 4975 ft) line of sight on my trial. It only takes a couple of seconds to put on and take off so that I can continue to use my Chinese backpack to carry the P2V+. I might even have gone further but I'd forgotten that I'd set 1500 metres as my range limit DUH!! At least I now know the DJI range limit works!!

    I used fpv booster app to give me the fpv range incidentally, that was still going strong at 1500 metres. Yes I'm aware of the "fpv booster could fry the wifi unit" debate but I've been OK with it so far and now have some arctic silver to give better heat sinking on that unit. I'm also now aware of the SWR discussion on this thread too but my logic is that most of the energy must be propagated forward to give me that sort of range using the stock 5.8 ghz antenna.
     
  8. J.James

    Joined:
    Apr 21, 2014
    Messages:
    1,882
    Likes Received:
    162
    Location:
    Upstate NY
    I used one of them that I made out of a pcs of thin sheet aluminum and flew it straight out till it would lose signal and rth and verified the results with the flytrex flight data. It went a lot farther then it does without it.