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What frequencies/components for FPV and Flight control?

Discussion in 'Photos and Video' started by Videoguy, Sep 13, 2013.

  1. Videoguy

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    Hi, I'm putting together an FPV system and a new Flight TX/Rx, but the more I read the more undecided I become. Here's what I know:
    I travel a lot with the Phantom, but rarely fly in urban areas, so 900 MHz seems like a good option.
    I will be building a larger UAV next year, probably a Hex, so I want to invest in a quality system now, right from the start.
    I mostly do aerial video, with a Sony Rx-100, no gimbal. I plan on getting an HDMI converter http://www.quadrocopter.com/Freefly-HDM ... p_612.html
    and a switch, so I can use an FPV cam as my Primary for flight, switching to the Sony cam to frame during the shot. http://www.readymaderc.com/store/index. ... cts_id=472

    I like the Futaba 8FG Super. I’ll need a lot of channels, and I can see the possibility for using more in the future.

    So 900 seems like a great way to go, but what Flight TX frequency should I pair that with? 2.4 just doesn’t seem like it will give me the range I need. Is 1.2 a viable option?
    I won't even get into antennas, but I’ve pretty much decided on an 8” monitor; while goggles are cool and immersive, my main goal is to get great shots. And although I don’t have a gimbal on the Phantom, on my next copter I probably will.

    Help! Any and all info is really appreciated!
     
  2. martcerv

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    All depends on what you are trying to do, for general flying within 1.5km a 2.4 radio 5.8 video setup works quite well. If your wanting to either fly longer range or behind lots of objects youd be looking at UHF radio and 1.2 video I think and this is likely what I will do for my next quadcopter.

    Im still just using the stock radio and been pushing it to its limits, it shows weakness behind any objects but my DJI AVL58 video setup works good enough for anything I need out of the phantom atm. I will be getting a futababa radio soon and this should do me fine for now and will upgrade to something like dragon link or another UHF radio addon later. Video wise probably go to 1.2GHZ once I want to do more deep penetration type flying through forests but I am quite impressed at what I can get from the 5.8 video.

    Its much better then many people get out of fatshark or immersion 5.8 setups in terms of range and low alti or behind a few trees even a house or 2. The stock radio dies quite regularly in such situations but my video feed has still been better then I expected at 5.8GHZ.

    Realistically I think I can do 1.5km LOS with the video and inside 500m with a few obstructions and an upgraded 2.4GHZ radio will be good enough for this sort of flying. Going the lower frequencies wont be for extreme range just better control and video when behind lots of objects. If I could get 500m deep into a thick forest that would be all I need and I think dragonlink and 1.2GHZ video will easily do this as shown by others.

    Here is an example of whats possible with my current setup and just using the toy radio from DJI :lol:
    [youtube]http://www.youtube.com/watch?v=FQHY5zXXk5E[/youtube]

    Here is an aerial showing the location, I am at the bottom right of the line which is 500m long and I went a little past that distance on these flights. Also behind a few trees and pretty low altitude stuff too with no video issues but one loss of radio.
    [​IMG]
     
  3. Videoguy

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    Thanks for all that info and the video. Yeah, I've read a little about UHF, I think I'll look into that more. Just a little while ago I also read about how DJI is swapping the freqs for their new version, the Vision, apparently due to a lot of flyaways. And I also read that some here are saying that 2.4 is such an overcrowded band that it may be one cause of flyaways. But yeah, flying through/behind forests is one of the things I like to do too. Anyway, thanks for the info!
     
  4. LJ35

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    Location:
    North Georgia, USA
    I've upgraded my TX, and I'm trying to decide on video frequency as well. I do not need to go 2km, but I do want to get behind a tree or two and not be limited to LOS even at fairly close ranges.
     
  5. martcerv

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    If your using 2.4ghz radio its still not going to be great at going behind objects but a good 5.8 setup will be a pretty good match up with a good 2.4 radio. 1.2 video will allow more penetration but it may get you into trouble with control unless you also go lower frequency for that. I think having the video as the weaker link is a bit safer then the other way around as losing control is much worse then losing video. If you fly to your videos limitations which are well within the limits of the radio it is a better way to go. Thats why I just upgraded my tx to a futaba 8fgs as I got myself into trouble quite a bit using stock radio and the dji 5.8 setup that easily outdid it in both range and penetration.

    [youtube]http://www.youtube.com/watch?v=cBKTYLcctZ4[/youtube]

    Above is my last video shot with stock radio pushing the limits deliberately flying behind trees up to 700m away. You can see my launch site and the thick line of big trees between me and the golf course. Most of this flight was keeping the phantom well below the tree line and video was still ok but had a couple radio glitches that were close to disaster as I had the same on the next flight causing a crash after losing radio at the wrong time. I think that shows quite clearly with this dji 5.8 setup you arent limited to los but for extreme penetration youd need uhf radio and 1.2 video.