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Hartwig

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Everything posted by Hartwig

  1. The signal ground here is always 0V. Sorry, I should have been posting a more dedicated schematic. How about this one? Maybe you need to play around a bit with the values of R1,3,5. But anyway this schematic shows the principle. If you built the circuit according to that schematic, you will have anice biased output at a DC offset level of roughly 2.5V. Also you are able to adjust the video level in a sensible range so you will end up with a signal level of 1Vpp when correctly terminated with 75ohms. If you want to use it as an output buffer stage, just add another 470uF Cap in series
  2. Great! In case you consider to modify the circuit, or to add several outputs you might like to use a circuit like the one below. It's actually the default for a simple audio amp stage, but with a little changes, you get a nice video buffer stage with biased output and also variable amplification to adjust the video level. (Just remove C2, change R4 to 470ohm and replace R2 with a 1k var Resistor. Maybe play around with R1,3,5 by reducing their values, if needed) I'm using it in my DIY diversity receiver and it's perfect. Just take a Video-suitable Op-Amp (for example LT1207 or a MAXIM
  3. -AT-mieczotronix: How did you provide the symmetric power supply? The circuit you mentioned, as well as the 4066 needs symmetric PS or biased input signals.
  4. Had a bad experience on a windy day, too. However, the wind was too strong to get back to the field, and my plane was about 1.3km away, still. So I tried to "gently" (while bumpy wind) prepare it's heading and behaviour, although gliding was out of the question. Then I could just watch it going down, trying to figure out where it will touch the ground. All of that was shortly before sunset, and the next 4 hours we weer searching for it in the dark and didn't find it anymore. So, the next day with the help of the video we found it. This was a real lecture to me!
  5. Gil, it actually doesn't matter if it comes from Australia or Switzerland, as they're both outside european community. But if the value (marked outside on the packaging) is below 20$ for commercial, or below 40$ for a gift, there won't be any extra taxes. If it's above that, there will be, sometimes huge, taxes charged for it, as well as extra weeks of delay while the parcel sits inside customs offices, waiting to be processed.
  6. If you want the data being displayed on a simple LCD , this should be fairly easy from a technical point of view. You might like to try this forum: www.mikrocontroller.net
  7. Hi Jeff, I received my Beta Kit yesterday here in germany. Just to confirm that everything went fine with shipping and customs, in a reasonable timeframe :-) Cheers, Hartwig
  8. Thomas, I guess your RC TX is pretty good if you can still control your plane at a distance of 1500meters, or maybe my system is not optimal... I have a very nice video downlink, but I get so many glitches and 2 days ago I lost control of my plane and had a very bad crash because it didn't respond at all to any command anymore and it was at about 700m distance and ~120m Altitude, which still should be ok (unless someone used my channel...) Can you tell me which RC-system (TX and RX) did you use for that? Cheers, Hartwig
  9. Hi Mr.RC-CAM, thanks a lot for your efforts and results! Good to hear that at least something is similar to what I have on my systems, so there might be hope :-) I think you're right regarding the OSD. I did a few tests yesterday without the OSD and got better results. However, I will investigate more into this direction. Maybe reducing the video levels and low-pass-filtering the OSD's video signal might help, even though I get noise as well with the video coming from the camera. Do you maybe have some screenshots of the video signals displayed on an oscilloscope? I'd like to compare my
  10. Hi Thomas, could you send me those pics as well, please? I'm testing the Sony ExView Black and white, but I would of course prefer color. Thanks a lot in advance. Cheers, Hartwig
  11. Mark, I think that's right, they can drain a lot of power, but they can carry heavy loads, too. But the main thing in my opinion is the stability that they offer. There are about 60-70 developers working together on it, and they are very effective. I saw videos which prove incredible stability. You could just put the RC-Control aside, go to the toilet and return a few minutes after, and the QuadroCopter will still be in the same place and heigth where you left it, even in windy conditions. It's just amazing.
  12. -AT-Mr.RC-CAM: I tested with two 623s and a Comtech Receiver and got the noise on all of them, however it's better on the Comtech receiver. But I can reproduce it also with the Rangevideo TX 1000mW. I noticed that lots the lawmate sounds pretty popular and as I understand that you and Thomas are using them also. And you seem to be fine with them. Maybe it's related to temperature, that some part in the TX gets too hot and causes a drift where the receiver's PLL is overextended and can't handle it anymore?! But it's strange that on the Airwave receivers the noise just starts when a signal
  13. How many channels does it control? I suppose there is no support for altitude, just heading, is that correct? I would like to try something like this in my Easystar, but I'm not sure if this can work at all. What do you think? Is there a chance that it works with my EM-411? Cheers, Hartwig
  14. -AT-mieczotronix: I thought of something similar, and the problem is that this local sync generator must be exactly in sync with the original video signal, and keep free running when there's no signal to lock to, or even worse when the signal that comes in is total crud and might mess up the locking circuit. If these problems are overcome then this is a great solution. (Another option would be to sample the video signal and put it out again. So after the AD/DA conversion a new generated video signal is there, and stable. But would be again HUGE :-) Just my 2 cents, Hartwig
  15. I'm looking forward to get the kit and test it in various combinations of TXs and RXs. I will post the results then.
  16. That program is called DGEarthTracker, you will find it here: www.dgadv.com It requires the VTG and GLL NMEA commands from the GPS receiver. On the EM-4xx receivers those seem to be disabled by default, so you have to enable them by sending the following strings to the EM4xx: $PSRF103,05,00,01,01*20 (enable VTG) $PSRF103,01,00,01,01*24 (enable GLL) And it works great! I got GoogleEarthPlus as well and I definitely prefer EarthTracker, because you can configure more parameters and it works seemless. However, it's shareware, but only $10 once. And it's definitely worth it. Cheers
  17. Most definitely! You can listen to it when attaching the video goggles or my hifi system. Exactly the same behaviour. Also when I move my hands around near the TX or the RX, the noise varies a lot. Very similar to what some of you might have experienced with old TVs... You can listen to it in the mp3 file attached. noise.zip
  18. - Which Rx are you using during the shown scope example? =>The RXs are AWM623. - Are the audio outputs (with the recommended caps) terminated, or are they allowed to freely float? Does the noise go away with a 10K ohm loads on the R/L audio? How about 1K? => The audio output (R is used, L is not connected) is AC coupled (22uF) loaded with 10k. Loading with 1k doesn't help either :-( - Any chance the board layout of the Rx is allowing coupling between the video and audio? The pixel data is very fast rise time, so coupling can occur if the layout/wiring is not careful. =&g
  19. I attached a screenshot of the video- and the audio waveform at the output of the receiver. The video input signal of the TX gets just a few letters from the OSD and black from the camera, and no signal is fed into the audio input of the TX. At the peaks in the video signal you can see spikes with a curve similar to a discharge of a capacitor after it. If I reduce the level of the video signal at the input of the TX, it doesn't affect the spikes in the audio. Does anyone have an idea what's happening? Does anyone experience similar effects? Any help is very much appreciated! Cheers,
  20. What exactly do you mean with "information lost"? The module is onboard the plane, so that means as long as the plane and it's electronics are alive and the battery is full enough, the information gets burned into the video picture in realtime, and transmitted into the air. So as soon as you get close enough to the plane (aka video transmitter) to receive a usable signal, you will see the video with all the data information onscreen. Does this answer your question? Sorry if I misunderstood. Cheers, Hartwig
  21. -AT-qnzkrew: I am using both DZL and TinyTrak, switchable on the plane. It depends on what Visualization software you would like to use (APRS or anything else which requires straight NMEA input), and on the behaviour of your video TX/RX equipment as well. If you are interested in details regarding setup of the TT or DZL, feel free to contact me. Cheers, Hartwig
  22. -AT-Mark: Can you make any rough guesses when it will be available and at which price?
  23. Will you use a seperate battery for all electronics stuff or do you intend running all gear from the main battery (motor as well) ?
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