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Old Jan 04, 2016, 06:44 AM
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Question
UK 5.8GHz only 25mW, whats the range?

The UK limit for power at 5.8GHz looks to be 25mw. What sort of range could I expect to get using this power with standard antennas, assuming it is line of site and also away from a built up area. Has anyone any advice about using above 25mW in the UK?
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Last edited by BillyBag2; Jan 04, 2016 at 10:48 AM.
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Old Jan 04, 2016, 07:17 AM
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Read here:
http://www.truerc.ca/news/rf-link-budget-2

With a good receiver and good omni antennas, I reached 600M with 1mW.
If you use a directional antenna at one end, you will fond that 25mW is plenty.
Approximate range can also be calculated using www.maxmyrange.com

-Hugo
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Old Jan 04, 2016, 08:01 AM
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Thanks, this is reassuring.
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Old Jan 04, 2016, 11:25 AM
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The furthest I have flown with 25mw is about 800M. I have not tried further because my RC radio telemetry starts reporting Low RSSI.

The secret to good range is an high quality receiver and high gain antenna. I have a FR632 receiver and Pepperbox antenna. I get a solid signal at 800M.


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Old Jan 06, 2016, 09:22 AM
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I've gone 2km on 25mW. Of course this was with a directional antenna (Pepperbox - same as HugeOne's X2-air) on the receiver. This is not typical, though. HugeOne and I are professionals on antenna design and theory. However, 1km is certainly sustainable on 25mW.

-Alex
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Old Jan 06, 2016, 10:35 AM
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Thanks. I have "invested" in a helical antenna too. The same handedness as the TX (I hope). More out of curiosity than anything else.

Hopefully the rest of the kit is in the post. In theory it will fly out of the box.

I'm sure from this thread that flight skills will limit my range to start with. I did not want to be disappointed because the UK legal kit was under powered.

I will try and remember to report back on my experiences from the other end of the FPV spectrum. I have in the back of my mind that a linear antenna with receive a circular signal. Is this correct? I think there may be a linear (looks like a wifi router antenna) or a clover leaf for RX. Was going to compare the two. Is it true the clover leaf is more robust against multi path issues? Also I think it has a greater vertical angle? I'm not sure if the antenna performance will be dominated by quality so I will pick and mix to start and see what happens.
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Old Jan 06, 2016, 11:47 AM
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Quote:
I have in the back of my mind that a linear antenna with receive a circular signal. Is this correct?
Yes but with a 3dB loss (40% range reduction)

Quote:
Is it true the clover leaf is more robust against multi path issues?
True if another circular* antenna is at the other end of the link.

*Not all antenna are circular even if they claim to.

-Hugo
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