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UK/European Regs for Output Power

Discussion in 'FPV (First Person View)' started by Hughie, Dec 1, 2014.

  1. Hughie

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    I have a P2 which I am looking to upgrade to an FPV solution.

    I was suprised to learn that despite all the 600mw/1000mw 5.8Ghz transmitters available in the UK, that when operating (in the UK) transmission on 5.8Ghz is limited to 25mw.

    Is this a realistic output power to run an FPV over?

    Is anyone using 25mw, and if so what performance are you seeing and have you had to optimise your setup to get it to work acceptably.

    Thanks
     
  2. noiseboy72

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    25mW is good for about 50'...

    OK, with decent matched antennae and a high sensitivity receiver, 500m is possible, but realistically, for analogue video, 25mW is far too low IMHO. Take into account poor antennae matching and loses associated and you are probably down to 10mW or so.

    100mW is a good compromise, as the effective radiated power is probably only about 50mw, so this is not far away from the legal maximum and can give acceptable results up to 500m or so with little technical knowledge.

    I have both a 25mW and a 600mW TX and the legal one is basically unusable.
     
  3. Hughie

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    Thanks for the reply.

    I assume you are in the UK/Europe, how do assess the risk of using a 600mw TX.
     
  4. saltire

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    What risk just buy the 600 and use it .Folks are also using 2watt amps for even more fpv distance .
    If you worried about it then just get some antenna upgrades .
     
  5. noiseboy72

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    The air absorption of 5.8GHz is fairly high, let alone the blocking effect of buildings etc. so I am not too worried about directly interfering with anything else in that band, but harmonics and intermodulation could affect adjacent frequencies - particularly when using some of the more budget high powered transmitters. Video is quite a wide band signal, so can wipe out a lot of bandwidth in one go.

    The Immersion TXs seem to have very stable RF performance and compared to a cheap 2W TX I tried, used much less power, was lighter and gave a better picture.

    To the best of my knowledge, there have not been any prosecutions or even complaints about using higher power TXs for FPV downlinks, but as the number in use is still fairly low, that's not to say that things could change.

    Legally, you are not allowed to fly over or close to towns and cities, so interfering with home users is unlikely, but fly around the countryside where there can be point to point links and it is possible to cause interference.

    I think a little common sense is all that's required to run higher power without causing problems for anyone.