Frequencies

Discussion in 'ALTA' started by Martin Osborne, Aug 7, 2016.

  1. Martin Osborne

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    Hi everyone,

    I'm having some issues with what I think is interference from my 5.8GHz FPV on my Connex signal.

    Here is a list of every device that uses radio frequencies currently on my setup:

    Movi, Movi controller, Wedge 2.4GHz Can’t be changed
    Connex 5.8GHz Can’t be changed
    FPV 5.8GHz
    Alta 2.4 GHz Futaba 14SG
    VPSystems CamRemote 433MHz
    GPS 1575MHz and 1227MHz Can’t be changed

    So what's the easiest/best/cheapest route to getting the FPV off of the 5.8 band? Seems I can't put it on 2.4 because of interference with Movi control. I can't add a 1.3 FPV without interfering with GPS and harmonic interference with 2.4. And lower frequencies (900mhz) need bigger antenna, get cumbersome etc. Or am I wrong?

    I could have moved the Alta to another channel to put FPV on 2.4, but because the Movi, Movi Controller, and Wedge can't be changed from 2.4, this idea won't work.

    I don't need miles of range, just a good solid link to 501m.

    Any ideas?
     
  2. Pete Maughan

    Pete Maughan Member

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    Latest Connex firmware does allow some frequency changes I believe. Still same range but might help.
     
  3. Andy Habin

    Andy Habin New Member

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    I'm having similar problems with the Connex. Everything else about my whole rig is performing very well, but the Connex is seriously letting me down.
     
  4. Mark Hoffman

    Mark Hoffman Active Member

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    I would suggest moving FPV video tx to 1.3ghz with a low pass filter.
     
  5. Andy Habin

    Andy Habin New Member

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    Thanks Mark, I'll look into it.
     
  6. Martin Osborne

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    I was warned that doing that would decrease the range of 2.4GHz equipment, such as the Alta and the Movi. Even with the filter. Has anyone here tried this?
     
  7. Mark Hoffman

    Mark Hoffman Active Member

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    1.3ghz (in the US they are generally 1280 or 1258mhz) is close to being a harmonic of 2.4ghz but the low pass filter (it only allows rf below a set limit to pass thru) helps with that a lot it also keeps the vtx from interfering with gps. I have had both 5.8 and 1.3 on my larger machines and haven't seen a decrease in range. I would also recommend only using a VTX with a reasonable amount of power, a 400mw 1.3 vtx will easily go for several miles of range with standard cp antennas. If I had to venture a guess, many people probably are having problems because they are using VTX with to much power. It is a better option to upgrade the VRX and antennas to increase analogue video range and performance.
     
  8. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I agree with you Mark....it seems that the common belief, when it comes to Tx power is "if some is good, more is better...." And that just isn't true. In my experience, the antennae make the biggest single difference without injecting crosstalk noise back into any of the other systems. The good quality right-hand circularly polarized antennae I've had the best results with are the "Bluebeams" from IbCrazy (Alex Greve, and he isn't!). You can get these for the different frequencies we tend to use: http://www.getfpv.com/catalogsearch/result/?cat=0&q=bluebeam

    Andy.

    Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. :(
    The Ground Is The Limit™
    ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
     
  9. Martin Osborne

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    I see they are selling 3.3ghz transmitters on that site. A whole new spectrum...
     
  10. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Yes. 3.3 Ghz does offer the advantage of a relatively uncrowded frequency band -- which will make it quite popular.

    Errr....of course, if it becomes that popular then it will no longer be relatively uncrowded... :)

    I believe one needs an amateur radio operator's license to use 3.3 Ghz in the USA legally.

    Andy

    Forensic Software & sUAV / Drone Analyst : Photographer : Videographer : Pilot (Portland, Oregon, USA): Trees=2, Ground=1, Props=11. :(
    The Ground Is The Limit™
    ---------- Forensic Drone Analyst : Forensic sUAV Analyst : Forensic Unmanned Aircraft Analyst : Forensic Drone Expert
     

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