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FPV Antenna Configuration Questions

Discussion in 'FPV (First Person View)' started by scdavis74, May 25, 2015.

  1. scdavis74

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    I am new to FPV setups, so please bear with me. I apologize in advance if this is covered on another thread and I missed it.

    I have a P2 with a Black Pearl Diversity monitor that came with 2 rubber ducky antennas. The tx on the Phantom was the stock DJI mushroom. Out of the box I was getting really bad video noise and almost complete static at about 30m out and same at about 60m up. I did some research and it looked like the Fat Shark / ImmersionRC RP-SMA 5.8GHz Circular Polarized SpiroNet Antenna FPV was highly recommended to increase FPV signal distance. So I bought those and put them both on the Black Pearl in Diversity mode. However I still had issues with signal drop out at the same short range. So I replaced the DJI tx with one of the RHCP's on the P2 and put a rubber ducky back on the Black Pearl. So I currently have both the RHCP and rubber ducky on the Black Pearl and RHCP as the tx. This has given me a much better signal at longer distances (about 500m before getting bad noise). I have since done a lot of research on how each of these antennaes work and the pros and cons of each one. And now I have some questions:

    1. Would I benefit from getting another RHCP on the Black Pearl and having one straight up and the other bent at 90 degrees.

    2. Would it be better to get a LHCP for the second antennae?

    3. Or am I better off keeping the rubber ducky as the second antennae so that I have more omni directional coverage?

    4. What is the best configuration here?
     
  2. thestone11

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    If you are looking for performance, get rid of the rubber ducks! Don't spend your money on fatshark spironet antennas! They are just ok.

    For long range, helical antenna and patch antenna will be the ones. Only drawback, they are directional, you have to point the antenna towards the bird to get good reception.

    My setup gives me clear video feed up to 1.5km, I am sure they can go further. But currently my radio can only go up to this range. I have a Aomway helical from hobby king and blue beam ultras (mad mushroom on monitor, air screw on bird)
     
  3. scdavis74

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    So, I went back out this afternoon to the exact same place where I got great FPV signal almost 600m out, and flew the exact direction and had interference again within 30m. ARGH!!! When I reoriented the Fat Shark RHCP rx antenna in a different direction, There was no significant change except for when my fingers were touching the antenna. I reached up and held on to it with two fingers and the FPV became crystal clear in full color....perfect. However I can't hold on to the antenna and fly at the same time. Anyone know why this happens and if it's an indication as to what my signal problems are?
     
  4. TeamYankee

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    1. Yes, get another RHCP and maybe a directional helical (not too many turns as it would be too directional!) (RHCP only) for the other antenna port - the helical would be directional and you would need to (roughly) point it at the Phantom to use it properly. If you use a patch antenna then it will be linear polarised, not circular right handed.
    2. Do not mix RHCP and LHCP - they won't work very well at all, that's the whole point of it.
    3. Lose the rubber duck... the RHCP is omni directional anyway.. point it UP, not at the quad, that's the Helical's job.
    4. see above...

    The RHCP antenna you have is great for "omni" all around reception, but not much good if you point it at the quad. They all receive from the sides much better.
    :)
     
  5. TeamYankee

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  6. Hughie

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    This is quite well done and informative (in particuar, omni-directional v Helix and why they should be combined)

     
  7. JustinJames

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    On my Phantom 2 I am largely content with the Blue Beam Ultra attached to the Immersion600Mw 5.8Mhz Tx, and one on the FlySight Black Pearl diversity monitor. I have the FlySight antenna which came with the monitor as the second Rx antenna. Question: would two Blue Beam Ultra antennae on the diversity monitor produce a better image - or does the monitor take the better signal and display that?
     
  8. thestone11

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    Since it is a diversity monitor, two different types of antenna will give you a better result. Since the monitor will pick the one with the stronger signal when receiving the signal.
     
  9. JustinJames

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    Ya,makes sense. Thanks.
     
  10. DGRAY3981

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    Im so interested in FPV. I find it so amazing after watching that video on this thread I take it I should get a 9db antenna instead of a 12 db, is that correct?
     
  11. Hughie

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    That depends on what range yu are after and the range and quality of your system depends to lesser extent too on what vTx power and what vTx antenna you are using. The key point made by the video is not so much that you need x dbi, it is more to do with getting both near and far reception by combining a pair of vRx antennae each of which is designed to look after one aspect. The easiest way to decide what FPV system to use depends on what range you want so I would start there, and ask for recommendations for components for that. Also you should mention which aircraft you are using it on.
     
  12. rebelyellNC

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    Hey DGRAY, welcome to the forum. Yes, FPV is fascinating and addicting. One caution I would share is to be very careful with flying by FPV if the bird is out of sight. It takes some experience with different events, like close calls, that will inform you when to push the envelope and when to bring 'er home. I would recommend some sort of OSD, as remaining battery power is one of the most important considerations when flying FPV. I got caught up in the excitement of watching the scenery below and lost my bird on March 12 when it was 1100+ meters out and OUT OF GAS! It only took a few weeks of grieving and I had my replacement bird. See my sig for some examples of FPV equipment that outflies the transmitter signal and still has a clear picture.

    Fly safe and let us know how it's going and what hardware you end up with...
     
  13. Edward Czajka

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    I did some field testing with various antennas and learned quite a bit. For my testing, I found a post in the desert about 200m away to use as my target. I sent through several configurations, and put it together for everyone: