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Diagnosing issues with antenna modifications

Discussion in 'Phantom 2 Vision + Mods' started by Morgon, Sep 8, 2014.

  1. Morgon

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    Earlier this weekend, I took the time to install the FPVLR Stage 2 kit on the repeater and the transmitter.

    Today, I went to use it in an open field, and was very disappointed. I am certainly not going to blindly pass blame on the antennas themselves, but rather I'm interested in ways to properly diagnose what the problem might be.

    I have all 3 antennas installed - the pinwheel and dome on the repeater, and the small 'turns' (what's the proper name for this?) on the transmitter. I kept losing Control connection at just 1000 feet distance (less than 100 altitude), and had times with 'laggy' video or full broken FPV connection, despite the very clear LOS. This is a dedicated flying field, so general interference is minimal.

    Obviously I could probably just reconnect the stock antenna and repeater connections (btw, does that lined shield in the RE700 repeater act as the antenna?), but what other things could I look for before going through all of that? For those familiar with accessing the underlying Linux subsystem, are there any tools that would help me identify transmission issues?

    Also, as an aside, why the long throw on the dome? Seems like an awful lot of cable for just having to stick it on the top-side of the repeater (unless I'm doing that wrong, but everything I've seen suggests it sticks to the top of the repeater so that the top of the dome points to the quad).

    Thanks for any advice.
     
  2. VINITA

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    Im experiencing the same outcome as you. I have ordered the birdside 2.4 antennas to see if that helps. I guess the next step is boosters? I was also thinking that maybe I actually do have more 5.8 control range than I think I do, but with the 2.4 dropping out I really dont know.
     
  3. rrmccabe

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    Are you line of site (LOS) or do you have trees in the way.

    The fact you are losing it on the video side as well as control side would indicate you do not have something blatantly wrong with just one side.

    Do you have any pictures of your dome install? And what kind of range were you getting prior to the Stage2 install.

    I have went over 8200' with just a stage 2 with clear LOS. Dense trees will take you out for sure but its much improved in the trees over the stock unit.
     
  4. Morgon

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    You know, I have been (re-)reading the main FPVLR thread, and I may have had the control antenna oriented improperly, but would it make that much of a difference at 1000 ft?

    Am I correct in thinking the 5.8 is supposed to point towards the Phantom (like a gun/barrel), rather than perpendicular (like the stock antenna)? Is it finicky enough to require you to keep it pointed directly at it, or should I still have solid performance at relatively close range (up to say, 1500 ft?) at just about any orientation?
     
  5. kondorfpv

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    Hi, please post pictures we will try to find out what the issue is.

    it will make more than 1000ft difference if it's not aimed properly.
    TOny.
     
  6. kondorfpv

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    Very nice thread, and I wonder why I have not gotten any email regarding possible issues.
    There are usually different issues that could lead to poor performance, positioning of the cables inside the wifi extender (please attach pictures of the insides),
    poor orientation, or path that gets blocked by another antenna or a tablet, simple things like these can cripple your rf system.

    The only way to diagnose these is by process of elimination and that starts with taking pictures of both the innards and the exterior positioning of these antennas.

    Tony.
     
  7. Morgon

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    Pictures are coming, but are delayed - looks like I stripped not one, but two of the hex screws from the Repeater the last time I closed it up. Once I can get back inside, I'll take those pics.

    (Hardware folk: Suggestions to fix these screws, as well as replacements?)
     
  8. Will Gardner

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    It is critical to make sure that the antenna connections are very tight. I purchased the stage four kit, had it scope tested and immediately went out and bought two 8mm open end wrenches. If they are not tight then the ground is compromised. Because I travel frequently with the drone I find myself screwing and unscrewing the 7 antennas. Properly tightened they work very well
     
  9. Morgon

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    Well, the JB Weld stuff didn't work, so I had to break my way in by drilling into the two hex screws. I have a ticket open with HeliPal to see if they might know a source for those screws; otherwise I'll have to dig around for regular Phillips-heads to replace them.

    In any case, I'm attaching some pictures of the setup from inside the repeater. I was getting connection problems from the DJI Vision app to the bird itself, and some 'laggy' video when operating it from 800+ feet. I realize that the dome isn't completely pointed at the Phantom, but 800 feet seems awfully close for that to matter... am I completely wrong?

    But anyway, you'll see the pigtails definitely don't touch anything else. So I'm a bit confused.

    I added them to an imgur gallery because I didn't feel like resizing them to fit the board. :)
    http://imgur.com/a/oQg7z

    The Tx isn't much to look at, but I've included it anyway. The connector sits where the connector goes.
    http://imgur.com/a/O8NIH
    As always, your help/feedback appreciated.
     
  10. Morgon

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    Don't suppose anyone has any other thoughts/insight? The connections are pretty tight, both the pigtails (which granted, are either on or off) and the antennas when they're screwed in.

    Is there some way to use a multimeter to determine whether I have proper current or something? (I'm not an electrical engineer, so you'd have to tell me what I was looking for :-\ )