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Airbender

900 MHZ poor reception

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Friends,

I need some help fine tuning my 900 MHZ FPV system. I purchased a 900 MHZ 500 Mw system from Range video about 1.5 years ago. I have used it infrequently primarily because I get such lousy performance from it.

I have some experience in RF so I know a few of the basics.

Problem: Whenever the TX exceeds ~75' from the RX, the signal quality drops dramatically. I see the "noise" lines across the screen, or the video picture drops completely. I have experimented with the following possible solutions:

1) I initially had the TX+cam mounted on a Trex 600. The camera itself was mounted underneath on a separate camera frame and the TX was near the rear the the helicopter. I was careful to route all of the video lines away from other power or RFI/EMI power sources. The Tx uses its own separate power source. The cable from the camera to the TX goes thru a toroid ring (10 wraps) and is close to the TX. Result = Still having signal drop issues.

2) As you can see from the photos, I have utilized four different omni style antennas on the TX. Each style TX was used at both vertical and horizontal orientation. The largest omni is a 5 dbi I purchased from L-Com. I used the second large omni on the RX, also in different orientations. I have even tried different combination's of both large and small omni's pictured on the TX and RX. Still having signal drop issues.

3) I then purchased a large panel/patch antenna rated at 12 dbi to be used on the RX. Again using different omni antennas at different orientations on the TX, I was getting only marginally better signal quality, but still having poor performance overall.

4) I then repeated the above listed trials using a large foamy airplane (Multiplex Mentor). I mounted the camera, battery, TX & omni under the tail, on a flat aluminum plate (see photo)far back away from the nose containing the electronics. Still having performance issues.

I do not have a recorded video....yet.

So, here's my theories:

1) Range video product is junk, or I got a dud, or both.

2) I need a more powerful tx, like this model:

http://www.nghobbies...products_id=292

3) I need a different model TX, like this model:

http://hobbywireless...&products_id=71

or this one:

http://www.dpcav.com...page=1&featured

Any and all suggestions are welcomed

TIA to all in advance

Any suggestions would be helpful.

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