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kstrach

Suggestions Needed for Improving Wireless Video

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Hello everyone. I normally frequent RCGroups, but figured that this would be a better place to ask about this. After a lot of searching on this forum, I have noticed that the question of how to improve video/TX range has been asked a lot. While improving range is my primary goal, I feel that my situation differs a bit from most, and therefore warrants yet another thread on this topic.

Here is my situation:

I am working to set up a wireless video system for a friend of mine who owns a large amount of land in Wisconsin. The property consists of small hills, prairie grass, farm fields, and a tree farm. His primary house is situated roughly in the middle of his property on top of a hill. I have been teaching him to fly trainer RC aircraft, but being more accustomed to full-scale aircraft, he does much better when flying from video. Our current system (see below) gives a crystal clear signal up to about 2500 to 3000 feet, but becomes almost unusable any further than this. We have the antennae hooked up inside his house in order to view the video live on a plasma TV. Interestingly enough, the range does not improve much when the antennae are placed outside and aimed at the aircraft. He would ideally like to be able to fly circuits around his entire property (from his living room couch) in order to explore his other houses and barns. I realize that flying an RC aircraft out of sight is typically frowned upon, but considering that this is private property located in a very remote region, the risk to others is extremely small. My friend does have a HAM license. I have attached a Google map of the area along with an estimate of our current range. He owns most of the land within the red border, and would therefore like to be able to reach most of it using the aircraft. Our aircraft transmitter (Eclipse 7) and receiver (Electron 6) have been successfully tested at this distance with no problems.

My current equipment (all purchased from Black Widow AV) is as follows:

Black Widow AV 2.4GHz Diversity Receiver (Frequency set 1)

KX-141 High Resolution Color CCD Camera - NTSC (now deceased :D )

2.4GHz 600 mW Transmitter (frequency set 1) with included whip antenna

2x 2.4GHz 8dbi Circular Polarized Patch Antennae

2x 2.4GHz 14dbi Linear Polarized Patch Antennae (both of these appear to give the best results)

post-5-1170214735_thumb.jpg

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Here is a list of the problems I would like to overcome:

1. I would imagine that being situated in the middle of the property makes this setup more difficult as extended range is required in every direction (~2 mile radius). I am trying to avoid the complexity of setting up a tracking antenna, and would prefer a permanent rooftop installation. I have looked into 2.4Ghz sectorized omnidirectional antenna arrays (Sharperconcepts), but it would seem that these are connected by signal splitters, and such a setup may just pick up more background interference than anything. Therefore, would I be correct in assuming that some sort of high-end diversity receiver is required for this? The Black Widow equipment has been great, and Bill has been extremely helpful. I just feel that for this application, something more extreme might be required. Does anyone know of a high-end diversity receiver which would allow more than 2 antennae to be hooked up simultaneously? Maybe something like the 6-way Diversity Receiver on the following site (RFCentral), but for 2.4 GHz. Or is there some other way to hook up a variety of antennae (such as an 8dbi patch antenna for close range along with an array of Yagi antennae for long range)?

2. While it may be more important to have better receiving equipment, it may not hurt to increase the wattage of the video transmitter somewhat. I have looked at both the 3 watt and 5 watt transmitters on the following site (Microcameras). Has anyone here used either of these transmitters, and if so, did you have to take any special steps to help protect the aircraft receiver from interference? Or would a 1 watt TX be sufficient?

3. I would like to install the antennae setup either on the rooftop or on an open area on the ground. However, with my current setup, the antennae are connected to the BW Diversity receiver with only about a foot of co-axial cable. I would ideally like to extend this cable to allow the diversity receiver to be placed indoors. I noticed that some people have mentioned the use of preamps in their setups. Would something like this help to avoid most of the signal degradation that is associated with increasing the cable length?

4. I had been using the KX-141 camera with success for almost a year before its demise a few months ago. However, I did notice that the camera had some difficulties adjusting to the difference in brightness between the sky and the ground, which often resulted in a dark picture. This surprised me as I expected this to be more of a problem for a CMOS pinhole camera. While this is a great camera for its size, I would like to see if I can find something even better, perhaps with better resolution (for viewing on a plasma) and better light handling capability. I've seen a lot of people recommend the KX-131 and 141, but can anyone recommend a really good CCTV camera (hopefully less than 8 - 12 ounces). Is there a practical limit in the number of displayed lines that can be transmitted over 2.4 GHz (NTSC)?

The equipment to pull this project off is obviously going to be expensive, but I am looking to achieve the best quality possible. I realize that I should probably only try to improve one thing at a time, so if anyone has any other suggestions that may help, they would be greatly appreciated.

Thank you in advance for all of your advice. This forum and its members have already been extremely helpful.

- Kris

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I think a 4way or more diversity sytem is the only way to do it. HERES MINE It must have a clear veiw 360deg so must be on the highest point. You can run power up and video down a co-ax.

For good video with this at 2 miles I would choose 1W minimum but your weak point will probably be your R/C link.

Terry

Edited by Terry

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What about using a repeater on the highest point. Being a ham radio guy I would try using another TX and RX and repeat the signal back to the house. It could be battery powered with solar for charging B) .

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