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2.4ghz FPV and UHF antenna separation

#1
How important is separation with 433mhz rc rx and 2.4 ghz video tx? I know that separation is key with 1.2ghz video and 2.4ghz to minimize harmonic interference, but I am wondering if the same applies to the aforementioned system. I am only getting about 200 meters with my 2.4ghz 500 mw video system which is very strange. However, my antennas are only a foot apart on the plane so that might be a problem, although I doubt that is why I have such a reduced range (foxtech advertised as 3 - 4 km). I am using standard dipole antennas for both. Would adding a coax extension cable to increase the distance between the two antennas be significantly beneficial?
 
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xuzme720

Dedicated foam bender
Mentor
#2
Can you give us more details? Like antenna type, components and such. Pictures are good for those of us that have trouble understanding the big words.
 

Craftydan

Hostage Taker of Quads
Moderator
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#3
Is the 200' in the air or as ground tests?

First off, look at the direction of your links with what is failing. your transmitter on the plane is not interfering with the receiver on your plane, otherwise you'd have a clear video picture as it falls out of the sky. It's far more likely the transmitter in your hand is interfering with the receive antenna for video.

Second, the standard derogatory term for those "standard dipoles" is a "Rubber Ducky" and deserves about as much respect as that implies. They will work, but never exceptionally well.

While it might not be easier/cheaper, changing out your antennas for something with better gain on both ends will greatly improve your video reception. The blue beam antenna sets made by IBCrazy are exceptional antennas, but they'll set you back ~$60 for the pair. You can make pretty-good-but-way-better-than-a-rubber-ducky antennas with the base of the antenna and some solid core wire. Check out David's Cloverleaf and Skew Planar articles for build guides as DIY options. A word of warning if you build one swirling clockwise, make sure the second one swirls the same direction!
 

xuzme720

Dedicated foam bender
Mentor
#4
Sorry, looks like I missed the dipole spec in the original post. As Dan suggested, a cloverleaf/skew planar will give you much better reception than the rubber duckies. One other thing to consider is penetration. 2.4 won't penetrate very far through thick woods and almost not at all through structures, but it IS better than 5.8. In flight, if you have line of sight, you should have more range even with the dipoles. What are the chances of moving the Tx further from the UHF antenna? Are you flying in a "noisy" area, as in a lot of external radio type interference?
 
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#5
I am not in a noisy area at all. What mainly troubles me is the fact that I am only getting 200 meters or so when it seems like there is no way that rc tx and video rx are inhibiting THAT much. I have seen range tests with rubber duckies to at least 2km so I don't know. I will have to try a new area/channel and experiment with changing the proximities between the video and rc components before I can jump to any conclusions.
 

xuzme720

Dedicated foam bender
Mentor
#6
I am not in a noisy area at all. What mainly troubles me is the fact that I am only getting 200 meters or so when it seems like there is no way that rc tx and video rx are inhibiting THAT much. I have seen range tests with rubber duckies to at least 2km so I don't know. I will have to try a new area/channel and experiment with changing the proximities between the video and rc components before I can jump to any conclusions.
There are higher gain dipoles which are probably being used with 2km range. It might be as simple as swapping out for a different set of antenna, but since experimenting is free, I'd try a few different channels to see if you are not just hitting a bad frequency. Then if nothing else, go for a new set of antenna's.

Check out some of IBcrazy's vids here on stoneblueairlines channel for some great FPV range help.
http://www.youtube.com/user/StoneBlueAirlines/videos
 
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