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Which antenna does which task?
511 5 2017-3-28
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WA5TEF
lvl.4
Flight distance : 124672 ft
United States
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Can anyone tell me which antenna on the RC unit performs the aircraft control and which antenna handles the video reception?  I have finally seen what the circuit of the antenna looks like but have not been able to discover the antenna question.  So, can anyone report this information?  I really appreciate any help.
Thanks,
Jim
WA5TEF
2017-3-28
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jwt-873
First Officer
Flight distance : 5946467 ft
Canada
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As far as I know, they both handle aircraft control and video.   The reason for two antennas is to improve signal quality through a method is known as spatial diversity.

Scroll down to "What is Diversity" in this link --> http://www.rcmodelreviews.com/spreadspectrum05.shtml

2017-3-29
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Mark The Droner
Captain
Flight distance : 2917 ft
United States
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My understanding of Lightbridge as it applies to the P3A/P is, one antenna is for control, and one is for FPV/telemetry.  This was proven in a thread on the phantom pilots site quite a while back, as somebody tested the controller with testing equipment and wrote a long technical OP.  I will try to find the thread - no promises.

The latest world distance record for all Phantoms was achieved just recently flying a P3A and by putting an amp on the FPV side and leaving the control side alone, as the pilot reported.  He knew he didn't need an amp on the control side because he had flown 19.4 miles linear distance (one-way) several months before.  

I would assume Lightbridge for the P4 is similar.

For some reason I suspect the left antenna is for control and the right is for FPV, but I'm not sure why I think that.  

Edit:  Here are some threads I found which might shed some light...

http://www.phantompilots.com/thr ... /page-2#post-671081

http://www.phantompilots.com/threads/rf-power-measurements.80442/

I can't find that particular thread but Phantom pilots is a good site to search

Edit #2:  Found the thread by accident in my bookmarks but I still don't know which antenna does what:  http://www.phantompilots.com/thr ... -frequencies.51693/
2017-3-29
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mic75
lvl.4
Flight distance : 3162733 ft
Australia
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Just block one antenna and see what it affects.
2017-3-30
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WA5TEF
lvl.4
Flight distance : 124672 ft
United States
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Yep, mic75, I blocked the left antenna, facing the controller, and the video link signal dropped from 100% to about 45%.  I did not try the other antenna.  
Thanks for the tip,
Jim
WA5TEF
2017-4-2
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mic75
lvl.4
Flight distance : 3162733 ft
Australia
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WA5TEF Posted at 2017-4-2 18:01
Yep, mic75, I blocked the left antenna, facing the controller, and the video link signal dropped from 100% to about 45%.  I did not try the other antenna.  
Thanks for the tip,
Jim

Glad to help, maybe block just the other one to be sure they work independently from each other.
2017-4-2
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