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Here are my video,grabbed on an eagle!!:

http://www.youtube.com/watch?v=qtGtmmYO7Vk

camaquila.jpg

Camera: 1/3"CCD Sony 480 lines

TX: 100mW 2,4ghz

battery: 12v li-ion

RECEIVER:

antenna n.1: 12db directional

antenna n.2 10db omni

diversity oracle

i tested all equipment at home,perfect signal,but there(near or far,same problem!)has a bad signal.Distance was around 100meters,but main problem is the poor signal,as you can see!Any suggest?

Edited by robyr1

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WOW!

Talking about a "bird's eye view" video!

Anyway, I can think of two reasons you have unsatisfactory range.

First of all your antenna choice. The 10dB omni you are using is of course an omni with a 360 degree azimuth range but due to it's high gain it has a too narrow lobe in elevation. The smaller 0-3dB gain omnis have a doughnut shaped lobe but in your case imagine that doughnut squashed flat. That means that as soon as the bird picks up height the you are getting out of the lobe's high gain area and the signal diminishes rapidly. As for the second 12dB patch, you obviously you have to point it to the bird's general direction.

The other problem is that unfortunately (or fortunately...) the eagle is not made out of styrofoam, balsa and plastic but it's a living creature made of flesh and bones. This means that it's body consists up to 90% of water and that's really bad for the microwave RF propagation, shading and blocking essentially the signal coming from the tx antenna when it's body gets in the way.

How to fix that last one I don't know... maybe a second antenna with a spliter of some kind, but it sounds complicated to do it right. Maybe a second Tx and antenna would be easier.

Dimitris

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I not an ornithologist but I don't recall seeing a bird flying inverted - at least not usually. :huh:

What about extending and mounting that TX antenna at one leg. After all it's just a wire in a plastic tube right?

D

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I don't believe that birds have a lot of fleshy mass to severely attenuate the microwave RF. So, that part would not worry me much. But if necessary, aerial location should be experimented with. This link may give you examples on how to mount things away from the bird: http://animal.discovery.com/convergence/sp...h/birdtech.html

The sample video was horribly MPEG compressed, so it is hard for me to say what needs to be improved. Are you complaining about the poor CCD camera (try another), or is the RF link not working well for you?

It is is RF link related: I couldn't tell what you were using for the Tx antenna, but if it is the white rod pointing to the left of the camera, then it seems quite long. If that is indeed the antenna, then what freq are you using and what is the length of the aerial? Also, generally speaking, it should be pointing vertically (either up or down) for best reception.

Lastly, if you aren't using one of the video systems that have proven to work well for our aerial apps, then you should plan on upgrading to one. Most folks find a world of difference when the right gear is installed.

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ok,

just a revision to my equipment list:

transmitter is just 10mW,not 100mw!and i used a small piece of wire as antenna.I think power is eanugh,but i have to solve the RX problem.My high gain antenna directional,is a 24db!!Is long 1 meter and the shape is seems like a pipe.The second is just a omni..

Tested at home,works very good!!perfect video,near and far,but in external,i have a bad noise at 1 meter from the rx!!

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I second Mr RCCam point of view, I would request for someone nearby you to check for the right TX aerial longitude for the freq your using and match it right (at least in impedance) if it´s wrong. Then point it up and start testing RX antennas again, but I would mix two directinal antenas instead of any omni.

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I second Mr RCCam point of view, I would request for someone nearby you to check for the right TX aerial longitude for the freq your using and match it right (at least in impedance) if it´s wrong. Then point it up and start testing RX antennas again, but I would mix two directinal antenas instead of any omni.

yes,but it's very strange: at home,the video it's very clear,from 1 meter to 10 meters...outside,from 1 meter image is very poor.

Video works over 100meter,signal sometimes go down,but image it's poor!

Here are my complete set used yesterday for eagle video,as you can see,i have a big antenna,and 2 different other antennas,and oracle diversity.

Any suggest?Is there a project to buils an high gain antenna??

eaglecamset.jpg

FOR MR. RC-CAM:

my system work at 2,4ghz (sure,tx and rx)and for the second test i used a different camera(hi res Sony 1/3") with a 4cm antenna.Quality is better,but rx signal is poor.I think wich the problem is on the rx station.

Edited by robyr1

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Well... I don't know if it's me, but on the video I didn't see any obvious RF problems...

The recording device seems to be skipping a lot of frames though.

I'd put the TX/antenna on the underside of the eagle. If it doesn't help I suspect defective/bad quality equipment.

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I don't know if it's me, but on the video I didn't see any obvious RF problems...

You are not alone. That was my feelings too. But frankly, the sample video was just too MPEG compressed to really understand what the issues are.

FWIW, the 4cm length is not typical for a 2.4Ghz system. It normally would be an accurately measured 1/4 or 1/2 wave length instead. I would check the existing range, then trim to 30mm, then check again. It should be as good, if not better, with the smaller length. This is not expected to help your existing problems, but should help out once you get the video issues resolved.

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www.onboardcamera.it/aquilaonboard.avi

here a footage better than youtube...i have to test it fitting antenna under the eagle...more suggest??

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So if you take the bird out of the equation does it work better? When you are testing indoors is the tx strapped on the bird?

I insist that suboptimal antenna placement could have a huge impact on the signal transmission, and more important than the bird's mass (which by the way is not negligible - this is an eagle not a sparrow) is it's body surface that shades the signal.

Out of personal experience with a tree branch out of my window, in line of sight with my friends home 500m away: Winter= perfect signal! - Spring just a few leaves - not too dense could easily look through the foilage - and the signal strength goes to heck!

I guess radio opaque items even if the are not directly in-line of sight are ruining the fresnel zone.

So if a few micrometer thick leaves can do such a damage - imagine what a few centimeters thick eagle flesh can do.

By the way, when testing indoors you might have reflexions from the walls,etc (one of the rare times that reflexions and multipathing might work in your favour) that's why signal blocking and/or antenna direction are not so important and you get this 10m range.

D

Edited by Dimitris76

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Well,

testin at home,signal perfect!test outside BEFORE fit on eagle,signal not clear...same problem at 100mt!I'm developing a new sistem with transmitter down the eagle.but i'm sure wich the problem is on the antennas.

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I notice some bad interference on the picture, are you using a switch mode psu ?

Terry

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Let´s see if we can round up the problem.

What kind of image can you get indoors and outdoors using a single receiver (remove the oracle unit from the system)? Do you get the same quality (good or bad) based on the same aerial combo on both receivers when testing them individually?

Every time (without exception) you test it inside you get a good image and every time yo test it outside you get a bad one?

Do you feel any improvement over the video TX changing to any of the available frequencies? If you get better images on lower frequencies then your aerial could be too long and it´s possible you need to match it with the appropiate tools.

Are you directly powering the camera and TX from the a 3S Lion Pack? no power regulator and no low voltage protection?

Using the camera indoors where you get a good image, is it still good 15 min after powering on. (try to see if any increase of temperature inside the camera/Tx can affect.)

Is it possible to have a broken (or about to break) TX aerial where the wire comes into the TX? No problems in the 10m range when moving it by hand? and farther outdoors does it make any changes in image quality?

That last one sounds stupid but happened to me once. I tested a RX aerial without realizing the aerial has a RP SMA connector (no pin inside the aerial SMA).

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Now there's a nifty RC plane, it has even got feathers and comes with a built in auto pilot that homes in on a piece of meat, where can I buy one? :)

Cheers,

Sander.

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Hmm, on the AVI I definitely don't see a RF transmission problem, looks totally normal to me.

The only point is those diagonal bands on the picture that indeed look like power supply noise. How do you power your equipment, and especially... can you give a more detailed explanation of what the problem you're complaining about actually is?

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Well,i powered complete system with a 10,8v Li-ion battery pack.I think wich that problem can be caused from a low quality recorder,i used a PDR100 recorder wich encode at 8mb/sec,wich is a good recorder,but not good for these videos..Next time i will use a miniDV recorder,wich encode at 25mb/sec!

What do you think?WIch that poor quality doesn't depend of RF problems??

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Well,i powered complete system with a 10,8v Li-ion battery pack.I think wich that problem can be caused from a low quality recorder,i used a PDR100 recorder wich encode at 8mb/sec,wich is a good recorder,but not good for these videos..Next time i will use a miniDV recorder,wich encode at 25mb/sec!

What do you think?WIch that poor quality doesn't depend of RF problems??

I got 2 questions:

1) Is there a big temperature difference between your indoor test and outdoor test? Meaning that there might be some detuning for some reason. Sorry, I know it sounds strange, it's just an idea.

2) Is there another RF source (WiFi or whatever) that might desensitize your video receiver?

cheers,

Hartwig

PS: Any chance using a groundplane antenna under(!) the eagle?

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Well,thanks for your cooperation guys!!

1)At home,temperature was around 20°,outside was around 10°!

2)there wasn't wifi and bluetooth devices there,was OPEN country!!far 5km from city!

i need to ask if can i fit antenna downside eagle..but as i can see on some DVD's,BBC had fitted antenna with camrera up!

Edited by robyr1

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OK.

There's definitely a recorder problem, as it skips a lot of frames. Maybe your SD card is too slow to cope with the high data rate. You could try using a lower quality, but if you have MiniDV gear available it's best to just use that.

But the lines shouldn't be the same problem. I'm still not convinced about your power supply, is the transmitter directly powered by the 12V, or is there some kind of regulator between the battery and the TX?

Otherwise I've noticed there was some noise on the audio channel, which *seemed* to match the places where interference changes, I'd try removing the microphone from the TX.

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i need to ask if can i fit antenna downside eagle..but as i can see on some DVD's,BBC had fitted antenna with camrera up!

Yes if I remember corretly they did but they also used a hand held dish with a helical feed. This required good aiming but was very effective at collecting signal.

Terry

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Yes,i have to buy a hand held dish with a helical feed,where???

Also to Kilrah: i use 3 mobile phone(li-ion)batteries like a battery pack,directly connected to camera and TX!

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Yes,i have to buy a hand held dish with a helical feed,where???

I don't think you will find one off the shelf, it't something they made special for the job. I was just pointing out that they used a circular polarized high gain aerial.

i use 3 mobile phone(li-ion)batteries like a battery pack,directly connected to camera and TX!

That sounds ok, it may be a problem on you receiver side.

Terry

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That sounds ok, it may be a problem on you receiver side.

Well, if the camera and Tx are 5V parts then that definitely is *NOT* okay, you risk setting things on fire and hurting, or killing, your eagle in the process.

Cheers,

Sander.

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