FPVLAB

image
Page 1 of 2 12 LastLast
Results 1 to 10 of 13

Thread: How much of a problem are tree's to 5.8?

  1. #1
    Navigator
    Join Date
    Jan 2015
    Location
    Australia
    Posts
    23

    How much of a problem are tree's to 5.8?

    I was just wondering how much of an issue flying a 5.8ghz system over tree's is? (Over and beyond is what I mean). If I fly a 5.8 system beyond 1 row of tree's (tallish pine 10m), would I then have to climb to make sure that the transmitter can be heard over the tree's? If so would this then mean, that the further I go out, the higher I would have to go to maintain video?

    Last note, that is an example of a Fresnel zone violation isn't it?

    Thank you in advance

  2. #2
    KD8YYX. DesignGeek's Avatar
    Join Date
    May 2014
    Location
    Wixom MI USA
    Posts
    120
    Yes, and no.--- It's an issue, You will get some minor glitches and cut outs in the the video due to obstructions, and fresnel zone violations. You will notice it.--- But you can fly through a lot of it. 5.8 not great in this respect, but I've had a blast with my system, getting low, and behind a few trees in the process.

    My recommendation would be to do some testing first in a wide open area, at med and then lower altitudes, to get an idea how sensitive your system is, Before you try to get behind a big patch of trees.

  3. #3
    Co-Pilot
    Join Date
    Jun 2012
    Location
    New Zealand
    Posts
    1,705
    Trees will attenuate a 5.8GHz system but, depending on the type of trees, time of year and how high you're flying, the effect may be less than you think.

    I fly my miniquads at a park and find that so long as I stay low (below the level of the lowest branches) I have no problems -- the gaps between the trunks are enough to allow plenty of signal through. However, if you get the leafy section of tree between you and the craft then you will lose a bit of signal.

    In a forest, stands of properly pruned pines aren't too much of a problem either (watch Metal Danny's miniquad videos) but flying behind a row of windbreak-pines (ie: ones that have all their branches right down to ground level and haven't been pruned) would likely cause some issues.

    The best way is just "suck it and see".

  4. #4
    Navigator
    Join Date
    Jan 2015
    Location
    Australia
    Posts
    23
    Ok, thanks heaps, this has helped me immensely

  5. #5
    Navigator _Milo_'s Avatar
    Join Date
    Jul 2013
    Posts
    430
    Heres an example, keep in mind the DVR recording blanks out to black while in the goggles its still staticky picture, and overall quality is a bit better in goggles, than on the DVR recording.
    2.4 control, 200mw 5.8ghz boscam transmitter, skyzone goggles.

  6. #6
    Crashing since 1985... kross1's Avatar
    Join Date
    Mar 2011
    Location
    Central NY, USA
    Posts
    2,132
    I fly above trees using 5G8 all the time, often 1/2 mile away. The trick is to think of a large fat cigar (or, side view of a fat/thick convex magnifying lens) between your video transmitter and receiver. If a tree/branch/hill/anything is in that space, you'll possibly get interference.


    So, above a forest is fine, flying past/beyond a forest is fine, as long as you are high enough to have a clear-line-of-site, which is a bit "fat". Testing will show you this. I highly recommend having a spotter the first few times, as you'll want to know how low you can safely go. I have seen a single row of trees/bushes (no leaves), a normal hedge-row, eliminate 5G8 at ~400 feet, with a quad behind the hedgerow maybe 10' off the ground.
    -KRoss1
    KD2GTU

  7. #7
    Navigator _Milo_'s Avatar
    Join Date
    Jul 2013
    Posts
    430
    What Kross said, yes over isn't a problem. Didn't really read your post right. In the video I posted I was more testing penetration and you can see when i was loosing video and climbed I regained video.

  8. #8
    Navigator
    Join Date
    Jan 2015
    Location
    Australia
    Posts
    23
    ahhh. Would something like a helical/directional antenna/patch help with this problem? (I'm not looking at getting one of those yet, this is more just out of curiosity now).

  9. #9
    Navigator _Milo_'s Avatar
    Join Date
    Jul 2013
    Posts
    430
    circular polarized antennas help with multipathing, a 5 turn helical will help with range, and still have a pretty wide beam. I tried an Aomway 5.8GHz 14dBi High Gain Flat panel antenna its only $15.00, and I thought performed really well, great range, and still a wide beam.

  10. #10
    Crashing since 1985... kross1's Avatar
    Join Date
    Mar 2011
    Location
    Central NY, USA
    Posts
    2,132
    But, they will not help with penetration thru foliage, much, as far as I know. These antennas give you more range, and are often directional.

    A fairly common antenna for use on Goggles is a 3-turn helical, such as http://www.readymaderc.com/store/ind...oducts_id=1089

    Note the picture shows bigger antennas, the 3-turn can go on goggles pretty easily.

    There is a thread here which talks about it a fair amount, http://fpvlab.com/forums/showthread....r-mad-mushroom . IBCrazy, the designer, says you can get ~150 degrees coverage, and a good amount of distance with this antenna (post#10). I have one on order to replace the Spironet RHCP I have been using on my goggles, guess I'll find out for sure this spring.

    Other FREQUENCIES handle video penetration thru trees/brush better than 5.8 gHz. The 2.4 gHz video is better, and the 1.3 gHz. is better than that.

    Of course you have to be careful with what VIDEO frequency you pick, depending upon what R/C frequency you are using.

    Likewise, what "frequencies" are already being used where you fly matter too, the "noise floor" that already exists.

    Generally, 5.8 video is a simple/easy way to get started, and people switch to 2.4 or 1.3 as they have a need/desire.
    -KRoss1
    KD2GTU

Page 1 of 2 12 LastLast

Similar Threads

  1. eagle tree RTH alt problem
    By voda in forum Eagle Tree Systems
    Replies: 0
    Last Post: 27th August 2014, 03:48 PM
  2. Eagle Tree RTH problem
    By Leprchonflyer56 in forum Eagle Tree Systems
    Replies: 17
    Last Post: 13th August 2014, 09:01 PM
  3. eagle tree elogger v3 power problem
    By Skygizmo in forum Eagle Tree Systems
    Replies: 1
    Last Post: 27th November 2013, 09:59 AM
  4. Problem with Eagle Tree OSD Pro + Guardian
    By MatthiasC in forum Eagle Tree Systems
    Replies: 18
    Last Post: 4th August 2013, 08:10 PM
  5. Eagle Tree with TBS core Problem
    By dreamdam in forum Eagle Tree Systems
    Replies: 3
    Last Post: 3rd May 2013, 06:21 PM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •