Cinestar Loses power during flight for a few seconds. Watch Video

Discussion in 'Cinestar 8' started by Chris Newman, Apr 27, 2013.

  1. Josh Lambeth

    Josh Lambeth Well-Known Member

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    I don't know that much about looking at the information you posted above but I am interested in learning more. How do you know if there is something you are getting that you shouldn't be seeing?

    Josh
     
  2. Shaun Stanton

    Shaun Stanton Active Member

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    @ Gary K

    Can you expand on this information. I do not believe that I said anything contradictory to what you have stated, I did say that a possible interference could have been the houses nearby with someone using a high gain antenna transmitting on the ISM.

    You pointed using a spectrum analyzer, I agree that is the best practice. I am in the process of getting one myself. So the question to be answered, is when should someone be concerned with a signal in that spectrum, i.e. at what ratio would the disturbing signal interfere with the 2.4Ghz device on the aircraft? Do you have a ratio that you use, such as if I see a signal in my spectrum I would consider it a threat, or do you just say "I see a significant spike that I don't like so I will stay out of this area to prevent cross talk?" Can you quantify the information?

    I figured I would ask since, as Andy pointed out there are a lot of transmission in the ISM as well as you mentioned fringe radiation from from cross harmonics.
     
  3. Dave King

    Dave King Well-Known Member

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    I would like to keep this thread alive as it has a lot of good information in it. Is Gary Kaplan still around I noticed he hasn't responded to a couple replies? Has anyone looked into a spectrum analyzier and what they would cost? I looked at aaroniasa but there's no prices listed.
     
  4. Gary Haynes

    Gary Haynes Administrator
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  5. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    And there's still the issue that if you use a RF spectrum analyzer it only gives you a ground-based reading -- not what conditions are like 400 feet above you where the aircraft can "see" a lot more potential RF sources.

    Of course, if there's a lot of RF interference on the ground, that will do nothing to improve ground-to-air control. But just because it's OK on the ground doesn't mean it will be OK in the air when the copter flies into a bubble of RFI.

    Andy.
     
  6. Dave King

    Dave King Well-Known Member

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    It's almost like we need a very small portable light weight version that can be strapped on the copter but there would be no way to get the data from it when its in the air.
     
  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    The Graupner Tx display the general state of the frequency channels they're using.
    It's called RF Status View and shows the the "view" from the Transmitter and the Receiver.
    See page 221 of the MX-20 manual.

    I suspect it will provide you what you need, Dave.
    Andy.
     
  8. Dave King

    Dave King Well-Known Member

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    I'll check it out thanks.
     
  9. Gary Kaplan

    Gary Kaplan New Member

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    Hey guys. I watch the thread and I thought I had responded but I got it
    comfused with the prop diam and pitch thread. Wrote too many long dissertations there. :)

    So, go out and get this one from Aaronia. Actually, the 6GHz model, the 6064 is just fine. By it
    From the US distributor directly. Do not buy it from Amazon or anywhere else. If you do the warranty will not be honored. The guys in Atlanta ( I think) are knowledgeable and very friendly.

    Make sure to get the high capacity battery option. You dont need the special front end filter option or expanded memory option because the base model has plenty of memory and you can download the data to your laptop which runs the diag software.

    The complete kit I bought cost a bit over $2500, but
    Well worth it when you consider thw price of the heli.

    http://www.aaronia.com/products/spectrum-analyzers/HF-6080-V4-Handheld-Spectrum-Analyzer/

    Gary
     
  10. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Gary K:
    On a related note, do you think there is any merit in using a double length whip antenna on the Tx? I'm not sure whether what are typically used are 1/8th wave, but, assuming they are, would a 1/4 wave antenna and its inherent gain improve matters? That's certainly what we do for WiFi in the same freq. band.

    The one's I've seen claim a pretty good SWR. eg. http://hobbywireless.com/index.php?main_page=product_info&cPath=73_76&products_id=76 with 9 dBi gain.

    Thanks
    Andy.
     
  11. Dave King

    Dave King Well-Known Member

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    Gary

    Thanks for the reply and the info. Can the get all the information you need from the handheld when doing a site signal analysis? Or do you need the laptop connected to it? What kind of information are you looking at when you do a site survey?
     
  12. Dave King

    Dave King Well-Known Member

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    Andy that's a good find. I have a longer antenna for the 5.8 system but I've been looking for a good one to try for the 1.2 system. I'm going to give this antenna a try and report back on how it works.
     
  13. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Dave: That antenna's tuned for 2.4Ghz not 1.2Ghz, so it will not work and may damage the Tx as the standing wave ratio may be too high....

    Andy.
     
  14. Dave King

    Dave King Well-Known Member

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  15. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    OK. Good. Glad you figured that out..... :)
    Andy.
     

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