Really Bad FPV reception with AVL58 - Video link included

[FASTFJR]

Stock Phantom 2 with 3 axis gimbal, iOSD, AVL58, HUB and Boscam 7 inch (tuned to C - 8)


For whatever reason I'm loosing reception around 30 meters. Clear sky, no trees.......pure line of sight loosing at 30-40 meters. Tried both stock and after market antenna as you can see in the video. The AVL58 does have a stock antenna on it. Everything is tight and batteries were fully charged. Any ideas of what I can do to REALY improve the reception? I was in the woods yesterday shooting a statue. At one point the P2 was 30 feet away, if I went behind a tree I lost all video. Everything else with the P2 is great.......


https://www.youtube.com/watch?v=WbLLOba2GIs&feature=youtu.be

 

[OneStopRC]

So far from what I can see... Antennas should be vertical at all times. Antennas radiate outwards, very little is send vertically, so the signal will be bad if the quad is above you.

I use Spironet antennas on my disco pro, I have better reception when it is at a distance. Right above me it sucks very much bad. What is the output of the VTX anyway? What Frequency are you on?.

 

[FASTFJR]

I switched to channel 8 on the AVL58 and the reception is much better now

 

[Jindalee10368]

Have been a licensed radio ham for over 30 years now...

You can suffer up to ~20db signal loss with cross-polarisation.

ie: if one antenna is horizontally polarised and the other is vertical.

This is easy to match between one ham station and another, but when an object is moving around in 3d space like a coptet it can be difficult to maintain the same polarisation!

Vertical is the easiest and most practical to try and maintain.

Be aware that a vertical's radiation pattern will diminish to almost nothing directly above.

Most of the energy is concentrated 10-30 degrees or so above the horizon. The higher the gain an antenna has, the tighter this radiated beam is. The lower the gain, the more broader the beam.

I see circular polarised antennas are available on 5.8 GHz.
You'll get an instant 3db loss if you have a linearly polarised antenna at the other end, but that may be a good compromise between larger signal fades when you bird is flying around.


Sent from my Galaxy S3 via Tapatalk 2

 

[chipwich]

Actually, that's not too bad for using the wrong antennas and flying in its radiation patterns' vertical axis as mentioned in the last post.