Downlink Antennas?

Discussion in 'Video Assist & Video Accessories' started by Josh Lambeth, Jul 22, 2012.

  1. Josh Lambeth

    Josh Lambeth Well-Known Member

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    Which types of antennas do you use and how do you like them? We are looking at upgrading the the cloverleaf style antennas since we are always seeming to have issues with our DownLink.

    Josh
     
  2. Gary Haynes

    Gary Haynes Administrator
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    Josh

    If you follow some of the other sites/forums in order of performance from low to high there are dipoles, cloverleafs and then the directional coils/patch antennas. After exchanging emails with IBCrazy guy, Alex, I switched from dipoles on my Iftrons to the cloverleafs and am getting solid results. I run a MondoExtreme for the TX and the Yellowjacket for a recv. You didn't say what freq you are running your downlinks at but 5.8 is really line of sight and even trees can degrade performance. You might want to try 900 to see if that helps.
     
  3. Josh Lambeth

    Josh Lambeth Well-Known Member

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    Thanks for the information Gary. We are running a 5.8ghz system using the 500mw mondo Tx and passport receiver. I was thinking of going with the cloverleafs from IBCrazy as well.

    Josh
     
  4. Gary Haynes

    Gary Haynes Administrator
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    Try the BluBeams from IBCrazy. Alex suggested that for the other antenna input to purchase a 5.8gHz Fan from TrueRC.net in Canada. That's what I have been using and with solid results.
     
  5. Josh Lambeth

    Josh Lambeth Well-Known Member

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    So your running the BlueBeams for the Tx and ONE of the antenna inputs on the passport then a 5.8gHz fan for the other input? Just making sure I am understanding correctly. Thanks for the info!

    Josh
     
  6. Nick Kolias

    Nick Kolias Moderator
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    I have antennas from Alex and Hugo at trueRC. Both the cloverleaf and skew wheels from Alex and Hugo's turbine and fan antennas have given me really good performance on 5.8.

    [​IMG]

    Gary already mentioned this but one thing we need to be especially careful of with 5.8 is that anything that gets in between the TX and RX will affect the signal. All the CF on the Cinestar makes it challenging to find a good place for a FPV TX that offers clean line of sight in all orientations- especially without dangling down into the frame. Cedar Beauregard posted a cool solution recently where he mounted his FPV antenna up on a mast to allow clear line of sight in almost any situation except flying directly overhead. I tried it recently myself and it works great. Our camera downlink antenna is a cloverleaf mounted to the rear landing gear strut and we've always had good reception from this position.

    [​IMG]
     
  7. Gary Haynes

    Gary Haynes Administrator
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    Josh

    Here's mine on the recv side. Also note that the BluBeams have two antennas and they are different. The TX is a 3 lobe and the Recv is a 4 lobe. You can see the 3 lobe Seattles photo.

    [​IMG]
     
  8. kimkonan

    kimkonan New Member

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  9. Josh Lambeth

    Josh Lambeth Well-Known Member

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    Awesome! looks good guys! thank you for that information. I am going to have to pick up a set. We have our Tx mounted on the rear leg of the gimbal as well and have noticed a much better performance in our downlink from our previous location.

    Josh
     
  10. Josh Lambeth

    Josh Lambeth Well-Known Member

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    Just ordered a set of the BlueBeams and an extra receiver ant. Should be here Tuesday! Just intime for a shoot Wednesday. I'll let you all know how they work!

    Thanks again for the information!

    Josh
     
  11. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    How did you attach the mast post to the hub, please, Josh?

    The mast seems like a good idea for both the FPV video and the RC transceiver (in my case the GR-24). I'm concerned about the RF absorbing characteristic of carbon fibre.
     
  12. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Don't you need to have the cloverleaf pointing up or down to have the sidelobes of the antenna matching the sidelobes of the antenna on the RX? I was looking at the polar diagrams for the Bluebeams and they suggest that the maximum sensistivity/power radiation is horizontal when the cloverleaf points up or down?

    Warning: My question is more based on ignorance than knowledge, but that's never held me back before. :)
     
  13. MIke Magee

    MIke Magee Active Member

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    Josh, how did you make out with this new 5.8 setup? Our existing patch system is almost unusable.
    tx,m
     
  14. Josh Lambeth

    Josh Lambeth Well-Known Member

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    There is a def. improvement in reception. I want to find another antenna location but it still is a night ans day difference.
     
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  15. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I've cut over to Bluebeams for the 5.8Ghz video downlink too. Much better quality, no dropouts. Mondo Stinger mounted horizontal on a gimbal leg so TX Bluebeam can be pointed up and horizontal. Dual Bluebeams on Passport -- both at same height, but separated far enough to give at least two wavelengths spacial diversity. Also mounted pointing up and horizontal. "Night and day difference" is a good description. Now if only we could get 1080p30! :)
     
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  16. MIke Magee

    MIke Magee Active Member

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    Thanks Josh and Andy. My camera person is going to kill me if I don't fix this. I notice that Gary (above) has 2 different RX models. Andy, sounds like you use two of the same, and prob the 3 lobe for TX. Any comments about that?
    -m
     
  17. Tim Joy

    Tim Joy Active Member

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    I've been thinking of using a micro servo that could "stow" the antenna on the legs for landing, then tilt it straight down for flight. That way it would be below the height of the camera and there wouldn't be a problem.
    For FPV, even using a 200mw 5.8ghz on a tall mast is enough to get perfect reception out past 1000-1500 ft. Never tested any farther.
     
  18. Josh Lambeth

    Josh Lambeth Well-Known Member

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    I too have been thinking about doing that! It would work well I think.
     
  19. Tim Joy

    Tim Joy Active Member

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    Only if my camera op remembers to hit the switch before landing! :D
     
  20. Josh Lambeth

    Josh Lambeth Well-Known Member

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    Yeah that would suck... with the radian we need to turn off the pan sensor or the copter starts rotating above the gimbal as soon as we land. Im always asking "Safe to land?" before I land to make sure... I could probably tie the servo in with the mode switch so as long as it's switched on the antennas down then when it's off it rotates up?
     

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