Flying during a live broadcast event - UHF Interference??

Discussion in 'Video Assist & Video Accessories' started by Drew Roberts, Feb 24, 2014.

  1. Drew Roberts

    Drew Roberts New Member

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    Hey Everyone,

    We will be flying during a live broadcast event this weekend. We will be using our heavy lift CS8 running two Spektrum DX8 radios.

    The shows head engineer is asking if their broadcast bands will interfere with our helicopter or vice versa. They will be operating wireless 802.11 b g and n bands. My understanding is that this is in the 2.4ghz range...

    Does anyone have any experience flying during live broadcasts or know if this will cause any issues with my radio systems. My number one concern is safety and do not want to fly if there is any chance of radio interference.

    Any insight would be greatly appreciated!!
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    If you get too close to one of their wireless access points (WAP), it will probably swamp your flight control system's signal -- and vice versa, if you get your transmitters too close to one of their systems it will swamp their signals. By too close, my guess would be less than two meters or less. Gary (who has more knowledge than I do about RF signals) may be able to comment further. What's at work is the so-called inverse square law -- the RF signal diminishes according to the square of the distance -- so it's really strong when Tx and Rx are very close, but decays very rapidly as the distance increases.

    The good news is that Spektrum was the first company to get into RC on the 2.4Ghz band and so their protocols use frequency hopping (where the transmitter and the receiver flip to predetermined different frequencies in lock-step), so if you lose a data packet on Frequency A, it will be on Frequency Q for the next packet (A and Q are just made up letters and have no significance).

    Bottom line: if you can keep your distance from their kit, as we say in the software business, "it should work." I've certainly flown around nearby WiFi WAPs at distances of around 10 meters or more and not had any problem -- but go near more powerful transmitters like a cell phone tower or a power line (which kicks out a lot of "sizzle" across the RF spectrum) and the inverse square law kicks in and the flight control signals get swamped....

    Proceed with caution!
    Andy
     

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