Run two 1.3gHz FPV TXs on one copter?

Discussion in 'Video Assist & Video Accessories' started by Steve Maller, Sep 2, 2014.

  1. Steve Maller

    Steve Maller UAV Grief Counselor

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    Assuming that I have two 1.3gHz FPV transmitter/receiver pairs that can be individually set to different channels, is it reasonable to believe that I can get clear video from both systems?

    I'd like to use 1.3gHz for both the video monitoring downlink from my MōVI, and a OSD FPV link from the copter itself. Obviously I'll have separate receivers and monitors/goggles on the ground.

    How clean are the 1.3gHz signals? I'm not going long-range...just a few hundred meters generally.
     
  2. Dave King

    Dave King Well-Known Member

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    I would love to do this as I hate my 5.8 signal. Technically it should work however you have to stay on the factory channel that Lawmate ships the units with. There is something in terms of being illegal to run any other channel frequency on the 1.3g spectrum. That's why they cover up the dip switches and even put glue or filler in there to prevent you from doing this. I can't remember where I saw that it was a law but I know it was some where on this board from one of our members. (Andy?) (Gary?)
     
  3. Tristan Twisselman

    Tristan Twisselman Active Member

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    I have been contemplating running 1.3 for my fpv setup and keeping 5.8 for camera op downlink, or running both on 5.8. The only thing i don't like about 1.3 is the antennas are like beach balls. I have a clover leaf for mine and it is a little bigger than a tennis ball
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    As a general rule, if one could lawfully run on different channels, I'd set the second transmitter two channels up or down leaving one "unused" channel between the two transmitters. Also, I'd try to make sure that there as much distance as possible between the two transmitters on the copter.

    Andy.
     
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  5. Josh Lambeth

    Josh Lambeth Well-Known Member

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    I can confirm it works... just can't tell you how I know how. ;)
    P.S. They were still within the legal channel limits.

    Josh
     
  6. Steve Maller

    Steve Maller UAV Grief Counselor

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    I did a test with two 1.3ghz TXs and two RXs on different channels and it worked great (outside of the USA territorial limits offshore, of course :rolleyes: ). Haven't tried it on the copter yet.
     
  7. Mark Harris

    Mark Harris Member

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    You really dont need circular polarised antennas on 1.2ghz. We like to call them "tumbleweed" antennas because they are so big. You only need circular polarised when you have external interference and you have a frequency that likes to bounce off things really well (giving you multipathing) - CP is perfect for 5.8ghz but pointless on 1.2.

    A well matched linear polarised dipole is far more effective at radiating power and receiving it. If you're only going a few hundred metres then two dipoles are going to be perfect!
    See these: https://www.fpvpro.com/antennas-dipole-video-transmitter
    They are perfectly tuned, and below 1.05 VSWR meaning you get maximum power out, giving you better signal and a cooler transmitter. Use them on your RX too.

    If you are flying far away, a 1.2ghz Yagi will get you much much better range than a circular polarised helical or patch antenna.
     

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