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5.8GHz Video TX Interferes with GPS


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#1 rmsteele

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Posted 04 February 2010 - 09:00 AM

I have a MikroKopter Hexa. I have added my Heads-Up-Display and am using a 500mw 5.8GHz video TX to transmit the video to ground. The video tx antenna is just a 5.8GHz simple omni antenna and is positioned about 13 inches and below the GPS antenna which is a standard commercial GPS patch mounted on top of a 2" square ground plane and is mounted above everything else. The GPS is a UBLOX and is mounted dirrectly on the other side of the ground plane.

If I power everything up together the GPS never locks any satellites. If I unplug the video TX it will lock 9 to 11 satalites in just a few seconds. Then I can plug the video TX back in and it will drop to about 5 or 6 satellites and hover aoround there for a while but eventually will drop below 4 which is not enough to maintain position hold or navigate waypoints.

I am limited on the amount of distance I can move the video TX antenna from the GPS antenna physical size limitations of the Mikrokopter. The GPS is mounted in center with the other electronics and the video TX is mounted out close to the end of one of the motor arms. the video TX antenna is connected directly to the TX.

I have had the same video TX much closer to a different GPS module with the same type of GPS patch antenna on a different aircraft, in that case it was a Trex-500 and they aced6 inches apart and worked just fine.

Doees anyone have any suggestions?

Thanks
Rick

#2 Mr.RC-Cam

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Posted 04 February 2010 - 09:26 AM

Need to see good clear photos of the installation. Also, have you asked the 5.8GHz supplier?
- Thomas

#3 rmsteele

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Posted 08 February 2010 - 09:20 AM

Need to see good clear photos of the installation. Also, have you asked the 5.8GHz supplier?



DSC00069s.jpg DSC00070s.jpg

As it turns out the video TX antenna is on the left and is only about 9 inches away from the GPS patch antenna not 13 as specified previously.

I have requested assistance from the TX manufacturer but have not yet heard back from him.

Thanks
Rick

#4 Mr.RC-Cam

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Posted 08 February 2010 - 01:44 PM

The physical separation is close, but there is still hope. Here are my recommendations:

Add a small Ferrite Toroid about 1-inch from the GPS module. It must have 10+ tight wraps of the GPS's host cable through it.

Do the same to the 5.8GHz Tx's cable; 10+ tight wraps and locate the Toroid on the cable so that it is about 1-inch from the Tx.

I didn't see the camera. What is it and where is it mounted?
- Thomas

#5 rmsteele

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Posted 09 February 2010 - 06:46 AM

The physical separation is close, but there is still hope. Here are my recommendations:

Add a small Ferrite Toroid about 1-inch from the GPS module. It must have 10+ tight wraps of the GPS's host cable through it.

Do the same to the 5.8GHz Tx's cable; 10+ tight wraps and locate the Toroid on the cable so that it is about 1-inch from the Tx.

I didn't see the camera. What is it and where is it mounted?


I will have to add some wire extensions to both the GPS and the TX but I will try this solution and see what happens.

The camera is a SN555 Sony CCD. It is mounted under the motor at the end of the red tube. Surprisingly I don't get any noise from the motor in the video.

Here is a YouTube Video of my first flight test of my Heads-Up-Display on the MikroKopter. As you will see it is still a work in progress. My video conversion program for YouTube left some white lines in the artificial that aren't actually there but you get the idea. Everything you see in the video is done on the aircraft.


Thanks
Rick

#6 Mr.RC-Cam

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Posted 09 February 2010 - 01:29 PM

Here is a YouTube Video of my first flight test of my Heads-Up-Display on the MikroKopter.

Ok, now you have some explaining to do. :)

I see an OSD with color! By chance is this PC based with the video overlay processing via the ground station and a bit of telemetry? However, if it's done all on-board the MK, then you've completed a remarkable achievement! Details man, details.
- Thomas

#7 Kilrah

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Posted 10 February 2010 - 12:45 AM

Everything you see in the video is done on the aircraft.


I remember seeing a screenshot of that something like 3-4 years ago, and nothing more since?
Long but good development :)

Edited by Kilrah, 10 February 2010 - 12:47 AM.


#8 andrei

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Posted 14 February 2010 - 06:33 AM

I'm still waiting on mine.
Mr Ricky Ricardo did you hear that?

Edited by andrei, 20 February 2010 - 09:17 PM.