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Hello, my first post to this forum..

is simply a link to my webpage:

http://www.webx.dk/rc/video-wireless/video.htm

please also to see this page:

http://www.webx.dk/rc/video-wireless/video-osd.htm

please fell free to add comments and suggestions

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yes , much heat and short lifetime is often the problem in such devices,

it was easy and cheap to improve it.

you know: for each 6 degrees you can lower the temperature, the lifetime will be doubled statisticly.

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Enjoyed your site Thomas.

Great info, thanks for sharing.

Mark

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I like the look of your UHF R/C system, well done. How hard would it be to adapt to 459Mhz ?

Terry

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Hi Terry, to change the RF frequency it is just some bits in the setup strings to the Micrel radio part.

the part it self cover a huge frequency span, it is designed to handle world wide low power uhf data links, I have also made a small PA that fit on top of the transmitter, now I have 300mW out, nice nice.. wild range !

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Thanks Thomas, I will be interested to see more details of this project. At the moment I use ready made modules then hack them to run the 455khz I.F into my own board with PLL and decoder. It's an expensive way to do it but my time is short and my design skills/equipment are not as good as yours. Is there any chance of seeing a scematic ?

Thanks, Terry

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just look inside the dir, you will find out my web page is full of free access to many dirs, with alot more files.

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Great job with OSD!

What resolution do you have there? It looks pretty good.

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Hey Cyberflyer, we can change the line txt draw routine to give us any size letters we can dream of, it is all in software, but i prefer them bigger so they can be read on low resolution cheap monitors, and even on VR googles.

right now after a few tests we have agreed on 32 chars on each line,

and 16 lines in total, chars are so big as possible on PAL.

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Did you run into a high resolution limit with ATMega? Can it do 600 horizontal pixels?

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nope, 32 chars on a line, and one char is 8x8 pixels,

so that is 256 pixels on a line, that is what we can handle in real time

with a 20Mhz AVR.

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at any murata distibrutors,

maybe ask for samples and sell the rest you dont need to rc-cam users !

or you can invite me to the sunny state, I would be happy to bring some :-)

it has been a while since I was in Florida, nice nice place !

Edited by ThomasScherrer

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The OSD looks fabulous. Nice work!

Regarding the GPS not working near your Video Tx, how close was it to the video antenna? I found the two need to be very close before the GPS is affected; Usually just a few inches distance will cure such problems.

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Thanks,

If a GPS is sensitive to jamming by video transmitters will be different from brand to brand, if you use the same GPS type and brand as mine, I would expect it to need more than 20 inches to perform ok, and 40 inches to perform 100% as if no tx was near,

If closer than 20" the GPS will not lock at power up.

all this was fixed by the little 2x3 mm filter, I am trying to find some more of those filters :-)

I have two of them EM406 GPS receivers and exactly the same problem,

also they crud when I use them in my car together with my tom tom pda, everytime I transmit on either 2m or 70cm hamradio bands, ok I output 50watts from my car.

Here in my office I just place the GPS modules near the window and get 3-5 sats, ok I know this is not uptimal, they can not see so much sky,

if any hamradio radio is in tx mode even at 5W the GPS would crud, after the filter is mounted, same number of sats, and I can tx 200watt and dont see any sat level change !

so a bandpass filter of some sort (SAW or HELIX) is NEEDED on a GPS, if it is wanted to co-exist with powerfull transmitters, some GPS modules have allready a filter inside, so you dont need to have the trouble with this. but they are much more expensive, and maybe not the SIRF STAR 3 chip set i wanted due to accurate position and better speed resolution and much higher sensitivity and much faster lock.

Edited by ThomasScherrer

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I use EM-406's too. I'd estimate that I have mounted them within 10 inches from my 600mW Lawmate 2.4Ghz Tx. No problems to report and satellite locks are good. Another fellow had mounted his EM-406 on top of a video Tx and could not get a satellite lock. Moving it just a few inches away restored operation.

But, as they say, every installation is different, even when they look the same. :)

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Here is the first fly tour from today !

http://www.webx.dk/rc/video-wireless/video-fly001.mpg

36MB in MPEG format, most people can play MPEG, right ? ?

its the first test with this video equip mounted,

picture of the instalation is here:

http://www.webx.dk/rc/video-wireless/video-osd.htm

it was really windy ! but I could not wait anylonger to test it.

The whole video clip is un-edited and the talk is in Danish sorry.

We also did a test with the original whip antenna on the rx,

and we say a bit more drop outs and less range possible with the whip.

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question about your GP Patch modifications:

Your dimensions for the original don't seem to match the dimensions listed by RC-Cam. Here's what he said in this thread: http://www.rc-cam.com/forum/index.php?showtopic=1000

Reflector is XY 4.20 x 4.20.

Driven element XY is 2.20 x 2.25.

Feedpoint XY is 1.100 x 0.750.

All in inches.

that means the bottom plate should be 106.7mmx106.7mm and the top plate should be 55.9mmx57.15mm.

You mention 14.7mmx14.7mm for the back plate, i'm assuming that's a typo?

Could that be why your performance before you modified the design was off a little?

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http://www.webx.dk/rc/video-wireless/video...05-whip-ant.mpg

See the original Whip antenna result, and compare it with the other video using patch ant if you like. After 6 tours today we are sure the Patch really helps alot on drop outs and range, actualy we have more video range than 35MHz RC range, due to cheap rx used, normaly the RC range was suficient, I newer flew that far away, but today we wanted to see how hi we could go, and 300m up, I got RC flips and could not see the plane anyway, next experiment will be with another 35MHz RX and binoculars.

Hi Pibb, yes you are right ! I sux :-)

I spell bad, sleep to little and drink too much, and dont read what I write :-)

I have updated my page with the right values just now:

http://www.webx.dk/rc/video-wireless/video.htm

Here the changed feed patch is 54.1 x 54.1 mm and 4mm height from bottom plate.

I did not change the bottom plate it is 10.74 x 10.74 mm.

Edited by ThomasScherrer

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now one more:

http://www.webx.dk/rc/video-wireless/video...-first20sec.mpg

note the pictures both from plane and ground are in phase !

also note the GPS is not perfect right after power on, but it is cold !!

so we could not wait.

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thanks guys !

btw what video format is prefered ?

what kind of compress is fine ?

I mean how many mb pr minute ?

you like mpeg ? divx4 ? divx5? cinepack? or what have you ?

I want the video quality to be ok, but also I like the file size to as low as possible,

the different codex compressors perform different,

and also they need much different pc power to either compress or playback.

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